20041224 Ver 1_Individual_20050317

Dufre
Power.
March 11, 2005
Mr. John Dorney
y???co
North Carolina Division of Water Quality (NCDWQ)
2321 Crabtree Blvd.
Raleigh, NC 27604
DUKE POWER
P.O. Box 1006
Charlotte, NC 28201-1006
?D
MAN 7 2005
Or,? W'T QUgU
l:c ^,4tOSTG Rj,ATERew.01
Re: Application for 401 Water Quality Certification-FERC License Surrender
Dillsboro Hydroelectric Project, FERC No. 2602
DWQ # 03-0179
Jackson County, North Carolina
Dear Mr. Dorney:
Enclosed for filing are an original and six copies of a completed application for 401
Water Quality Certification for license surrender of the Dillsboro Project, along with the
application fee of $475. As background, on July 8, 2003 Duke Power, a Division of
Duke Energy Corporation, Nantahala Area (DPNA) filed a 401 Water Quality
Certification (401 WQC) application with the North Carolina Division of Water Quality
(NCDWQ) for relicensing of the Dillsboro Project. Subsequently on September 5, 2003,
Duke requested that NCDWQ place a hold on processing the 401 WQC application for
relicensing of the Dillsboro Project until DPNA filed a license surrender application with
the Federal Energy Regulatory Commission (FERC) for the same Dillsboro Project. The
license surrender application for the Dillsboro Project was filed with FERC on May 28,
2004. Based on FERC's latest regulations, 401 WQC applications are to be filed with the
state 401 agency no later than 60 days following the Ready for Environmental Analysis
(REA) notice. The REA notice for the Dillsboro license surrender application was issued
by FERC on January 21, 2005.
At this point, DPNA is requesting that FERC process our license surrender application to
approve, as requested, the removal of the Dillsboro Dam and Powerhouse.I
1 When FERC approves the license surrender application, DPNA would withdraw its license application for
the Dillsboro Project. However, because it is possible that FERC may not approve DPNA's license surrender
www.dukepower.com
Please note that FERC issued a "Notice of Schedule Change for Applications" dated
January 27, 2005 for the relicensing applications in the Nantahala Area, including the
Dillsboro license surrender application. The tentative date for the "Ready for
Commission's Decision" for the Dillsboro license surrender application is now January,
2006.
If there are any questions, please call me at 704-382-5942 or Ed Bruce at 704-382-5239.
Sincerely,
MY A_??
Jeffrey G. Lineberger, P.E.
Manager, Hydro Licensing
Duke Power
Enclosure
cc w/ enclosure: Mr. Kevin Barnett, Asheville NCDWQ Regional Office
Mr. Steve Reed, NC Division of Water Resources
Magalie R. Salas, Secretary FERC
John Wishon, DPNA
application, DPNA is required to keep active its license application to renew the hydropower operating
license. Because FERC requires states to act on 401 WQC applications within one year, DPNA is required to
keep its 401 WQC application for relicensing active as long as the license application for the Dillsboro
Project is pending. This was accomplished by the withdrawal and re-submittal of a 401 WQC application for
the Dillsboro Project on June 30, 2004 (date-stamped by NCDWQ on July 2, 2004).
DWQ ID: 03-0179
FERC 401 WATER QUALITY CERTIFICATION
APPLICATION
FOR EXISTING FERC PERMITS
* SEND SEVEN (7) COPIES AND THE
APPROPRIATE FEE (SEE ITEM # 16)* OF THIS APPLICATION TO:
THE NC DIVISION OF WATER QUALITY
ATTN: AIR. JOHN DORNEY
2321 CRABTREE BLVD.
RALEIGH, NC 27604
(PLEASE PRINT OR TYPE.)
1. OWNER'S NAME:
Duke Power, a Division of Duke Energy Corporation, Nantahala Area (DPNA)
2. MAILING ADDRESS:
526 S. Church Street, P.O. Box 1006
CITY: Charlotte STATE: North Carolina ZIP CODE: 28201-1006
PROJECT NAME:
Dillsboro Hydroelectric Project (FERC License Surrender), FERC No 2602
PROJECT LOCATION ADDRESS (IF DIFFERENT FROM MAILING
ADDRESS ABOVE):
150 North River Road, Dillsboro, NC 28725
3. TELEPHONE NUMBER: (WORK) [phone]
4. IF APPLICABLE: AGENT'S NAME OR RESPONSIBLE CORPORATE
OFFICIAL, ADDRESS, PHONE NUMBER:
Mr. Jeffrev G. Lineberger, Manager Hydro Licensing, Duke Power, 526 S
Church Street, P.O. Box 1006, Charlotte NC 28201-1006
5. LOCATION PROJECT (PROVIDE A MAP, INCLUDING A COPY OF USGS
TOPOGRAPHIC MAP OR AERIAL PHOTOGRAPHY WITH SCALE):
TOPOGRAPHIC MAP OR AERIAL PHOTOGRAPHY WITH SCALE):
6.
7.
COUNTY:.Iackson NEAREST TOWN: Dillsboro
SPECIFIC LOCATION (INCLUDE ROAD NUMBERS, LANDMARKS, ECT.)
ISO North River Road: See attached maps-Attachment A
IMPACTED STREAM/RIVER: Tuckaselzee River
RIVER BASIN: Little Tennessee River Basin
CURRENT DIVISION OF WATER QUALITY (DWQ) CLASSIFICATION:
Upstream of Dam: Class C. TR; Downstream of Dam: Class C
(a) IS THE PROJECT LOCATED WITHIN A NORTH CAROLINA DIVISION
OF COASTAL MANAGEMENT AREA OF ENVIRONMENTAL CONCERN
(AEC)? YES 7 NO Q
(b) IF THE PROJECT IS LOCATED WITHIN A COASTAL COUNTY (SEE
PAGE 7 FOR LIST OF COASTAL COUNTIES), WHAT IS THE LAND USE
PLAN (LUP) DESIGNATION?
8.
(a) ARE ADDITIONAL PERMIT REQUESTS EXPECTED FOR THIS
PROPERTY IN THE FUTURE? YES H NO IF YES, DESCRIBE
ANTICIPATED WORK:
In association with the FERC approval of the Dillsboro Project License
Surrender Application and the subsequent removal of the Dillsboro Dam and
Powerhouse, a Section 404 "dredge and fill" permit Nvill be required by the
U.S. Armv Corps of Engineers. Along with the Section 404 permit required
for the dam removal, an associated Section 401 water qualitv certification
will be required from the NCDWQ for the actual removal work The
decommissioning of the Dillsboro Project includes the full removal to j?rade
of the existing Dillshoro Dam and Powerhouse on the TuckaseRee River. In
association with this option, the dam is to be removed to the original riverbed
over its full width and assumed pre-dam hank-to-bank width and depth
Removal will be accomplished by use of livdraulic equipment to remove the
dam in accordance with a stated demolition plan An excavator with a hoe-
ram attachment or comparable equipment will demolish the dam
Excavation equipment will remove and load out rubble and concrete
During the demolition process, river flow will be at various times and
sometimes in combination, diverted through the powerhouse, passed through
a notch in the dam, and/or passed over the partiallv demolished crest

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Approximately 16.0 acres in the Proiect
10. PROVIDE AN APPROPRIATE ENVIRONMENTAL DOCUMENT. THE
DOCUMENT SHOULD ADDRESS:
(a) DATA SHOWING THAT A 7QI0 MINIMUM FLOW WILL BE
PROVIDED
Historic stream flow data and associated flow duration curves for the
Proiect, including minimum flow data can be found in the original Dillsboro
Hvdroelectric Final License Application submitted on .July 23 2003 This
information is found in Section E2.0 of the Final License application Annual
and monthly flow duration curves are provided in Appendix 2 of the Final
Dillsboro License Application. Since the dam is proposed to be removed and
the flows restored to original levels, the inflow at this location will he equal to
the outflow. Thus, 7010 flows at this location will continue to be provided
(b) A COST BENEFIT ANALYSIS OF THE PROJECT SHOWING WHY THE
PROJECT IS STILL NECESSARY
The removal of the Dillsboro Dam is a major component of the Tuckasel!ee
Cooperative Stakeholder Team (TCST) and Nantahala Cooperative
Stakeholder Team (NCST) Settlement Agreement. The decommissioning of
the Dillsboro Proiect includes the full removal to grade of the existing
Dillsboro Dam and powerhouse on the Tuelcasegee River. Based on the
information provided in the Dillsboro FERC License Surrender Application
and the Environmental Assessment/Biological Assessment (EA/BA), Duke
Power believes that the preferred alternative and the best economic value as
part of the settlement agreements is full removal of the existing Dillsboro
Dam and Powerhouse.
An EA/BA was submitted to the FERC and other interested parties on June
2, 2004 (in association with the Dillsboro License Surrender Application) and
it discusses the removal proiect, Proiect related impacts and benefits, and the
other project alternatives. Duke worked with the NCDWQ, NCDWR,
NCWRC, NCSHPO, USFWS, USFS, and the Eastern Band of Cherokee
Indians (ECBI) in completing the necessary environmental, cultural, and
engineering assessments regarding the removal of the dam and powerhouse
A decommissioning plan and associated pre-removal, removal and post-
removal monitoring plan are also discussed in the EA/BA This FA/BA and
monitoring plan is provided as Attachment B and C to this application
(c) DESCRIPTION OF LENGTH OF BYPASS REACH (IF ANY) AND
MEASURES TO PROVIDE FLOW TO THE REACH IN LOW FLOW
CONDITIONS.
No bypassed reach is associated with the Dillsboro Proiect.
(d) MEASURES PLANNED OR TAKEN TO MAINTAIN DOWNSTREAM
WATER QUALITY SUCH AS ADEQUATE DISSOLVED OXYGEN.
In association with the Dillsboro Hydroelectric Project, dissolved oxygen
data collected in 2001 and the NCDENR-DWQ historical data, oxvIzen
concentrations consistently exceeded the minimum concentrations
established by state water quality standards for the TuckaseRee River. As
,%vith temperature, no discernable effect on dissolved oxviZen was detected
from the existing Dillsboro Project. A detailed analysis of dissolved oxygen,
is provided in Exhibit E (Section E2.9) of the Final License Application
submitted in July 23, 2003. Althou-h the Proiect currently has little effect on
water quality parameters and is in compliance with the state standards,
certain parameters such as dissolved oxvaen and temperature may slightly
improve with dam removal due to the reduction in impounded waters. Total
suspended solids (TSS) would increase, durin? the relatively short-term
(estimated 10-12 week) demolition period, although the majority of the
impounded sediments consist of tin-contaminated coarser bedload sands and
14ravels. A pre-removal, removal and post dam removal environmental
monitoring plan will be prepared in consultation with the resource agencies
hefore execution of full dam removal. This plan includes dissolved oxvRen
monitoring during the removal and post-removal periods. Monitoring is
important in determining if the goals and objectives of the removal project
are attained and that specific regulatorv conditions (e.g., state water quality
standards, Endanjjered Species Act Section 10) are met during both the
removal process and the post-removal periods. A preliminary pre-removal,
removal, and post-removal monitoring plan is provided in Attachment C of
this application.
11. WHAT IS THE SIZE OF THE WATERSHED 290 square mile drainage area
WHAT IS THE FULL-POND SURFACE AREA? 15.0 acres at elevation
1972.00 ft. NISL
12. YOU ARE REQUIRED TO CONTACT THE US FISH AND WILDLIFE
SERVICE AND/OR NATIONAL MARINE FISHERIES SERVICE
REGARDING THE PRESENCE OF ANY FEDERALLY LISTED OR
PROPOSED FOR LISTING ENDANGERED OR THREATENED SPECIES OR
CRITICAL HABITAT IN THE PERMIT AREA THAT MAY BE AFFECTED
BY THE PROPOSED PROJECT. DATE CONTACTED:
Letter from Brian Cole (USFWS-Ashevil le) on March 8, 2000 in association
with Project Section 7 consultation and subsequent letters/discussions with
the USFWS throughout the relicensinj! stakeholder process Subsequent
consultation with Marl: Cantrell (USFWS-Asheville) on November 14 2003
in association with the darn removal and Section 7/10 consultation
concerning the Appalachian clktoe mussel, as well several other Project
aaencv discussions.
13. YOU ARE REQUIRED TO CONTACT THE STATE HISTORIC
PRESERVATION OFFICER (SHPO) REGARDING THE PRESENCE OF
HISTORIC PROPERTIES IN THE PERMIT AREA WHICH MAY BE
AFFECTED BY THE PROPOSED PROJECT. DATE CONTACTED:
Letter from Renee Gledhill-Earlev (NC Dept. of Cultural Resources) on
December 16, 1999 in association with cultural resource consultation and
subsequent letters/discussions with them during the relicensint! stakeholder
process. Subsequent consultation with Renee Gledhill-Earlev on September
1 and 10. 2003 concerning the eligibility of the Dillsboro Dam and
Powerhouse for listing in the National Register of Historic Places
14. DOES THE PROJECT INVOLVE AN EXPENDITURE OF PUBLIC FUNDS
OR THE USE OF PUBLIC (STATE) LAND? YES ! NO E (IF NO, GO TO
15) None identified at present time.
(a) IF YES, DOES THE PROJECT REQUIRE PREPARATION OF AN
ENVIRONMENTAL DOCUMENT PURSUANT TO THE REQUIREMENTS
OF THE NORTH CAROLINA ENVIRONMENTAL POLICY ACT? YES NO
(b) IF YES, HAS THE DOCUMENT BEEN REVIEWED THROUGH THE
NORTH CAROLINA DEPARTMENT OF ADMINISTRATION STATE
CLEARINGHOUSE YES ? NO ?
IF ANSWER 17b IS YES, THEN SUBMIT APPROPRIATE
DOCUMENTATION FROM THE STATE CLEARINGHOUSE WITH THE
NORTH CAROLINA ENVIRONMENTAL POLICY ACT. QUESTIONS
REGARDING THE STATE CLEARINGHOUSE REVIEW PROCESS
SHOULD BE DIRECTED TO MS. CHRYS BAGGETT, DIRECTOR STATE
CLEARINGHOUSE, NORTH CAROLINA DEPARTMENT OF
ADMINISTRATION, 116 WEST JONES STREET, RALEIGH, NORTH
CAROLINA 27603-8003, TELEPHONE [phone].
15. THE FOLLOWING ITEMS SHOULD BE INCLUDED WITH THIS
APPLICATION IF PROPOSED ACTIVITY INVOLVES THE DISCHARGE OF
6
EXCAVATED OR FILL MATERIAL INTO WETLANDS: Not Applicable at
this time. Section 404 permit application to he submitted to U.S. 4rmv
Corps of Engineers and NCDWO after FERC approval of Dillsboro License
Surrender Application and before initiation of dam removal
(a) WETLAND DELINEATION MAP SHOWING ALL WETLANDS, STREAMS,
LAKES. AND PONDS ON THE PROPERTY (FOR NATIONWIDE PERMIT
NUMBERS 14, 18, 21;26, 29, AND 38). ALL STREAM (INTERMITTENT
AND PERMANENT) ON THE PROPERTY MUST BE SHOWN ON THE
MAP. MAP SCALES SHOULD BE 1 INCH EQUALS 50 FEET OF 1 INCH
EQUALS 100 FEET OF THEIR EQUIVALENT.
(b) IF AVAILABLE, REPRESENTATIVE PHOTOGRAPH OF WETLANDS TO
BE IMPACTED BY PROJECT.
(c) IF DELINEATION WAS PERFORMED BY A CONSULTANT, INCLUDE
ALL DATA SHEETS RELEVANT TO THE PLACEMENT OF THE
DELINEATION LINE.
(d) ATTACH A COPY OF, THE STORMWATER MANAGEMENT PLAN IF
REQUIRED.
(e) WHAT IS LAND USE OF SURROUNDING PROPERTY?
(o IF APPLICABLE, WHAT IS PROPOSED METHOD OF SEWAGE
DISPOSAL?
16. CERTIFICATION FEE
(a) IF THE IMPACT IS LESS THAN 1 ACRE OF WETLAND OR WATER AND
LESS THAN 150 FEET OF STREAM, PLEASE ENCLOSE A CHECK FOR
$200.00 MADE OUT TO THE NORTH CAROLINA DIVISION OF WATER
QUALITY.
(b) IF THE IMPACT EXCEEDS EITHER OR BOTH OF THE LEVELS IN (a),
PLEASE ENCLOSE A CHECK FOR $475.00 MADE OUT TO THE NORTH
CAROLINA DIVISION OF WATER QUALITY.
17. PUBLIC NOTICE IS REQUIRED FOR ALL FERC PROJECTS. PLEASE
NOTE THAT THE APPLICANT IS REQUIRED TO REIMBURSE THE
7
DIVISION OF WATER QUALITY FOR THE COSTS ASSOCIATED WITH
THE PLACEMENT OF THE PUBLIC NOTICE. REFERENCE 15A NCAC 2H
.0503(0.
SIGNED AND DATED AGENT AUTHORIZATION LETTER, IF APPLICABLE.
NOTE: WETLANDS OR WATERS OF THE US MAY NOT BE IMPACTED PRIOR
TO:
1. ISSUANCE OF A SECTION 404 CORPS OF ENGINEERS PERMIT,
2. EITHER THE ISSUANCE OR WAIVER OF A 401 DIVISION OF
WATER QUALITY CERTIFICATION, AND
(IN THE TWENTY COASTAL COUNTIES ONLY), A LETTER FROM
THE NORTH CAROLINA DIVISION OF COASTAL MANAGEMENT
STATING THE PROPOSED ACTIVITY IS CONSISTENT WITH THE
NORTH CAROLINA COASTAL MANAGEMENT PROGRAM,
OWNERS/AGENT'S SIG ATURE DATE
(AGENT'S SIGNATURE VALID ONLY
IF AUTHORIZATION LETTER FROM
THE OWNER IS PROVIDED).
Cmmty of Me&,I ft 1, b&U
State of North Carolina
Subscribed and sworn to before me, in my presence.
this day of_}' w1 I-CL
by I L L' ?L L,?LL-)-rr
Notary Public
My commission explresL?? K, ?C%a F
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ATTACHMENT A
PROJECT MAPS
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ATTACHMENT B
DILLSBORO DAM
ENVIRONMENTAL ASSESSMENT/BIOLOGICAL ASSESSMENT
12

ENVIRONMENTAL ASSESSMENT
AND
BIOLOGICAL ASSESSMENT
Future of Dillsboro Dam
Jackson County, North Carolina
May 2004
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Prepared For:
Po Duke
Power
A Duke Energy Company
Prepared By:
'-%?TA
Dcciuc •1'arbcll S Assuci:xtcs, 111c.
1'.....?k.?a? 1 . , r...?nl? , It, ?..il..l..? ?,r
Duke Power FINAL Dillsboro Environmental / Biological Assessment
TABLE OF CONTENTS
EXECUTIVE SUMMARY ..................................................................................................... ES-1
1.0 PURPOSE AND NEED ............................................................................................... 1-1
1.1 Purpose for Taking Action .................................................................................. .. 1-1
2.0 ALTERNATIVES INCLUDING THE PROPOSED ACTION ..............................2-1
2.1 Alternatives for the Dillsboro Dam ....................................................................... 2-1
2.1.1 Alternative A - No Action .............................................................................. 2-1
2.1.2 Alternative B - Partial Removal ................................................................... .. 2-4
2 .1.2.1 Engineering Analysis ........................................................................... 2-6
2.1.3 Alternative C - Full Removal ......................................................................... 2-9
2 .1.3.1 Engineering Analysis ......................................................................... 2-10
2.2 Alternatives for the Dillsboro Powerhouse .......................................................... 2-24
2.2.1 Alternative A - No Action ............................................................................ 2-24
2.2.2 Alternative B - Closure ................................................................................. 2-25
2.2.3 Alternative C - Complete Demolition and Disposal ..................................... 2-26
2 .2.3.1 Engineering Analysis ......................................................................... 2-26
3.0 AFFECTED ENVIRONMENT ................................................................................ ..3-1
3.1 Existing Information ............................................................................................ ..3-1
3.1.1 Local Setting ................................................................................................. ..3-1
3.1.2 Project Information ....................................................................................... ..3-1
3.1.3 Drainage Basin Hydrology ............................................................................ .. 3-4
3.1.4 Water Quality ................................................................................................ .. 3-5
3.1.5 Climate .......................................................................................................... ..3-6
3.1.6 Topography ................................................................................................... ..3-6
3.1.7 Geology ......................................................................................................... ..3-6
3.1.8 Soils ........................................................................................................... ..3-7
3.2 Natural Resources ................................................................................................ .. 3-7
3.2.1 Botanical and Wetland Resources ................................................................. .. 3-7
3.2.2 Vegetative Cover ........................................................................................... 3-10
3.2.3 Wildlife and Fisheries ................................................................................... 3-12
3.2.4 Land Use ....................................................................................................... 3-21
3.2.5 Floodplains and Flood Events ....................................................................... 3-22
3.3 Cultural Resources ............................................................................................... 3-22
3.3.1 Archaeological Sites ..................................................................................... 3-22
Duke Po%%er FINAL Dillsboro Environmental / Biological Assessment
3.3.2 Historical Resources ..................................................................................... 3-22
3.3.3 Previous Cultural Resource Studies .............................................................. 3-25
3.4 Recreation ........................................................................................................... 3-25
4.0 ENVIRONMENTAL CONSEQUENCES ............................................................... ..4-1
4.1 Introduction ......................................................................................................... ..4-1
4.2 Environmental Consequences for Dillsboro Dam ............................................... ..4-1
4.2.1 Alternative A - No Action ............................................................................ ..4-1
4.2.1.1 Environmental Resources .................................................................. .. 4-3
4.2.1.2 Cultural Resources ....................................................... ...................... 4-19
4.2.1.3 Recreational Resources ...................................................................... 4-20
4.2.1.4 Social Resources ................................................................................ 4-20
4.2.2 Alternative B - Partial Dam Removal .......................................................... 4-20
4.2.2.1 Environmental Resources .................................................................. 4-20
4.2.2.3 Cultural Resources ............................................................................. 4-25
4.2.2.4 Recreational Resources ...................................................................... 4-25
4.2.2.5 Social Resources ................................................................................ 4-25
4.2.3 Alternative C - Full Dam Removal .............................................................. 4-26
4.2.3.1 Environmental Resources .................................................................. 4-26
4.2.3.2 Cultural Resources ............................................................................. 4-32
4.2.3.3 Recreational Resources ...................................................................... 4-32
4.2.3.4 Social Resources ................................................................................ 4-33
4.3.1 Alternative A - No Action ............................................................................. 4-33
4.3.1.1 Natural Resources .............................................................................. 4-33
4.3.1.2 Cultural Resources ............................................................................. 4-34
4.3.1.3 Social Resources ................................................................................ 4-35
4.3.2 Alternative B - Powerhouse Closure ............................................................. 4-35
4.3.2.1 Natural Resources .............................................................................. 4-35
4.3.2.2 Cultural Resources ............................................................................. 4-36
4.3.2.3 Social Resources ................................................................................ 4-37
4.3.3 Alternative C - Complete Powerhouse Demolition and Disposal ................. 4-37
4.3.3.1 Natural Resources .............................................................................. 4-37
4.3.3.2 Cultural Resources ............................................................................. 4-38
4.3.3.3 Social Resources ................................................................................ 4-38
4.4 Endangered Species Act/Section 7 Consultation ................................................. 4-39
Duke Poser F NAL Dillsboro Environmental / Biological Assessment
4.4.1 Back-round Information ............................................................................... 4-39
4.4.2 Section 7 Consultation .................................................................................. 4-39
5.0 LITERATURE CITED ............................................................................................... 5-1
6.0 COMPLIANCE, CONSULTATION AND COORDINATION WITH .....................
OTHERS ..................................................................................................................... 6-1
6.1 List of Preparers ..................................................................................................... 6-1
6.2 List of Contacts ...................................................................................................... 6-2
6.3 Pertinent Regulations, Laws, and Executive Orders ............................................. 6-4
ATTACHMENTS ...................................................................................................................... A-1
ATTACHMENT A .................................................................................................................... A-2
REFERENCE GUIDE TO BIOLOGICAL ASSESSMENT (BA) SECTIONS WITHIN THE
ENVIRONMENTAL ASSESSMENT (EA)
ATTACHMENT B .................................................................................................................... B-1
AGENCY CORRESPONDENCE
ATTACIIMENT C .................................................................................................................... C-1
SITE PHOTOGRAPHS
ATTACHMENT D .................................................................................................................... D-1
ENVIRONMENTAL ASSESSMENT SIGNIFICANCE CHECKLIST
ATTACHMENT E .................................................................................................................... E-1
SEDIMENT STUDY RELATING TO THE REMOVAL
OF THE DILLSBORO DAM
ATTACHMENT F .....................................................................................................................F-1
FINAL DILLSBORO SEDIMENT CONTAMINATION REPORT
Duke Po«er
FINAL Dillsboro Ensironmental / Biolo-ical Assessment
LIST OF TABLES
Table 2.1-1.Operational flows provided by the upstream Duke Projects in association with
sediment removal ............................................................................................... 2-5
Table 3.1-1. Historical Stream Flow Data (cfs) Associated with the Dillsboro Project by
Month for the Period 1945 through 2000 ........................................................... 3-5
Table 3.2-1. Mussels Collected Immediately Downstream from Dillsboro Darn, Tuckasegee
River mile 31.7 (phrs= person hours, CPUE= catch per unit effort, Appalachian
elktoe CPUE in parentheses) ............................................................................ 3-21
Table 4.2-1. Summary of Impacts by Future Dam Alternatives ...........................................4-1
Table 4.2-2. Summary of assumed natural bed elevation, estimated distance between
transects, and calculated volume within Dillsboro Reservoir ............................ 4-7
Table 4.2-3. Amount of Reach 1 (above Dillsboro Dam and reservoir), Tuckasegee River,
covered by particles less than 12 mm as calculated from IFIM transect data..4-10
Table 4.2-4. Amount of Reach 2 (below Dillsboro Dam and reservoir), Tuckasegee River,
covered by particles less than 12 min as calculated from IFIM transect data.. 4-10
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Duke Po%%er FINAL Dillsboro Environmental / Biological Assessment
FABLE OF FIGURES
Figure 2.1-1. Plan and Section View of the Dillsboro Dain ........................................................ 2-2
Figure 2.1-3. Dillsboro Dam Removal Sequence ...................................................................... 2-11
Figure 2.1-3. Dillsboro Dam Removal Sequence (cont) ........................................................... 2-12
Figure 2.1-4 Dillsboro Dam Removal Sequence ....................................................................... . 2-14
Figure 3.1-1. Project Location Map ........................................................................................... . 3-2
Figure 3.2-1. Dillsboro Project Cover Type Map ...................................................................... 3-11
Figure 3.2-2. Dillsboro Project Fish Sampling Map ................................................................. 3-15
Figure 3.2-3. Dillsboro Project Aquatic RTE Location Map .................................................... 3-23
Figure 3.2-4. Dillsboro Project Floodplain Map ........................................................................ 3-24
Figure 4.2-1 Bathytnetric Map of the Dillsboro Reservoir ....................................................... .. 4-6
Figure 4.2-2. IFIM Transect Locations ...................................................................................... 4-9
F-1
Duke Power FINAL Dillsboro Environmental / Biological Assessment
EXECUTIVE SUAMINIARY
Duke Power, division of Duke Energy Corporation (Duke), has prepared this combined final
Environmental Assessment (EA) and Biological Assessment (BA) in accordance with the
procedures for implementation of the National Environmental Policy Act (NEPA) through the
U.S. Fish and Wildlife Service (USFWS) as stated by the Council of Environmental Quality
(USFWS undated). The purpose of this EA is to disclose, identify, evaluate, and determine the
actions that may be taken by Duke, the supporting federal and state agencies, and other
stakeholders in determining the future of the existing Dillsboro Dam. The assessment describes
and evaluates alternatives to the proposed course of action. Duke will use the results of this
assessment as an objective decision-making tool in addressing the future of the Dillsboro Dam
and Powerhouse.
In association with this EA, is a companion Biological Assessment (BA) to determine what extent
the above-mentioned actions may have on the federally listed Appalachian elktoe mussel
(Alasmidonta raveneliana). This biological assessment is prepared in accordance with legal
requirements set forth under Section 7 of the Endangered Species Act (16 U.S.C 1536 (c)), and
follows the procedures established through the USFWS's NEPA guidance and ESA guidance.
The Dillsboro Project is located on the Tuckasegee River near the Town of Dillsboro in Jackson
County, North Carolina (Figure 3.1-1). Duke operates this hydroelectric project under a license
from the Federal Energy Regulatory Commission (FERC) (FERC Project No. 2602). This
existing license expires in 2005, and the process of obtaining a subsequent license officially
began in 2000 Nvith Duke's release of the First Stage Consultation Document.
In pursuit of the subsequent Dillsboro license, Duke opted to pursue an enhanced Traditional
Licensing Process to gather meaningful and significant input from stakeholders on Project
operations and resource protection and enhancement (Duke Power 2003). In late 2000, in an
effort to identify issues and stakeholder interests in the Tuckasegee watershed, as well as the
upstream East Fork and West Fork watersheds, the Tuckasegee Cooperative Stakeholder Team
(TCST) was assembled. The TCST consists of stakeholders who represent various interests and
uses of the waters and related natural resources of the Tuckasegee River Basin upstream of
Bryson City. Included on the TCST are representatives of state and federal resource agencies,
local governments, adjacent landowners, resource users, basin-wide conservation organizations,
and Duke Power. The purpose of the TCST was to identify issues and interests related to the
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Duke Poser FINAL Dillsboro Environmental / Biological Assessment
hydropower projects on the Tuckasegce River and their operations, and using information derived
from the relicensing studies and other sources, develop a non-binding Consensus Agreement and
a subsequent binding Settlement Agreement (Duke Power 2003).
The TCST Settlement Agreement (Agreement), which was signed by the majority of members'
organizations in late October 2003, includes a Multi-Project Resource Enhancement measure of
the potential removal of Dillsboro Dam and Powerhouse. As stated in the Agreement "...the
Parties acknowledge that Duke Power worked with the USFWS, North Carolina Division of
Water Resources (NCDWR), North Carolina Division of Water Quality (NCDWQ), North
Carolina Wildlife Resources Commission (NCWRC), the North Carolina State Historic
Preservation Office (NCSIIPO) and the Eastern Band of Cherokee Indians (EBCI) and
complete(d) the necessary environmental, cultural resource, and engineering assessments
regarding the removal of Dillsboro Dam and potentially the Dillsboro Powerhouse. These
assessments evaluate (d) the potential effects of darn removal on aquatic species; determined the
extent of any cultural resources impacts, and considered the options of removing the
powerhouse." Therefore the need for taking action on this Project is directed towards providing
and satisfying the important resource enhancement initiative that will mitigate for the various
impacts of the DPNA Ilydro Projects, as described in the Agreement. In part, the removal of
Dillsboro Dam would provide mitigation for fish passage and instream flow requirements in
bypassed stream reaches on other DPNA Ilydro Area Projects.
The settlement agreement prepared and signed by the TCST, as well as the settlement agreement
prepared and signed by the Nantahala Cooperative Stakeholder Team (NCST), was filed with the
FERC in early January 2004. It was noted to the FERC that removal of the Dillsboro Project's
dam is a key component of the settlement agreements (i.e., significant gains in aquatic habitat in
the Tuckasegce River) and that Duke Power is preparing a Dillsboro Project License Surrender
Application, that includes decommissioning of the powerhouse and the removal of Dillsboro
Dam, for filing with the Commission by June 1, 2004. This EA/BA is an important component of
the Dillsboro License Surrender Application.
Based on progress in association with the above-mentioned Settlement Agreement, an initial
scoping meeting was conducted in which the preliminary details and proposed outline of the
EA/BA were described to the TCST stakeholders. Representatives attending this initial scoping
meeting included:
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Duke Poi%cr
FINAL Dillsboro Environmental / Biological Assessment
• U.S Fish and Wildlife Service (USFWS);
• Natural Resources Conservation Service (NRCS);
• U.S. Forest Service (USFS);
¦ Eastern Band of Cherokee Indians (EBCI);
• North Carolina Wildlife Resources Commission (NCWRC);
• North Carolina Division of Water Resources (NCDWR);
• North Carolina Division of Water Quality (NCDWQ);
• Duke Power
Subsequent discussions and ?neetings also included the Town of Dillsboro officials, Tennessee
Valley Authority (TVA) and the U.S. Anny Corps of Engineers (Corps).
In addition to this and several other issue update meetings, consultation letters (requests for
information) were sent to the above stakeholders and several local governments (e.g., Town of
Dillsboro). Responses from these stakeholders, as well as the verbal comments from the scoping
and update meetings were used to develop this document and address the major issues
(Attachment B). A draft version of the EA/BA was submitted to the agencies and interested
stakeholders on September 15, 2003 for review and comment. Agency and stakeholder
comments and recommendations associated with the draft document were compiled and
incorporated into this final version. These comments are found in Attachment B of this
document.
Based on both internal discussions and stakeholder discussions and the nature of the Project,
several issues were identified that will require detailed evaluation and are important in the
decision-making analysis in comparison of the alternatives. These issues are as follows:
Sediment Quantity and Quality
The stakeholders have identified that sediment accumulation in the Dillsboro Project is an area of
primary concern. Discussions and analysis concerning this issue focus on the estimated quantity
of existing sediment affected by the alternatives; quality (i.e., contamination) of existing
sediments; mobilization/transport of existing sediments; potential downstream sediment transport,
assimilation and distribution associated with the alternatives and any impacts; and any sediment
management techniques to be employed with the alternatives. Due to the importance of
accumulated sediment within the Project and the potential for impacts, project specific studies
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Duke Po%Ner FINAL Dillsboro Environmental / Biological Assessment
were conducted to determine the level of any sediment contamination, as well as sediment
quantities, downstream transport and deposition.
Aquatic Life
The stakeholders also identified that the alternatives may affect the abundance, types, and
movement/passage of aquatic life both upstream and downstream of the existing dam. EA
discussion and analysis addresses the existing conditions associated with the fishery and
macroinvertebrate resources and the potential effects to them from each of the alternatives.
Rare, Threatened, and Endangered (RTE) Species
The scoping process for this Project and subsequent field studies has identified two RTE mussel
species and their critical habitats immediately downstream of the Dillsboro Darn. These species
include the Appalachian elktoe (Alasrtti(Ionta raveneliana)(federal and state endangered) and the
wavy-rayed lampmussel (Lantpsilis fasciola) (NC Species of Concern). Two fish species, the
wounded darter (Etheostonta vulneralunt) and the olive darter (Percina sguantata), both NC
Species of Concern, are found immediately downstream of the Project. The only other RTE
species found within the Project is the aquatic Eastern hellbender (federal and NC Species of
Concern). This EA is required to address the effects of the alternatives on these species and also
discuss the protection measures to be potentially implemented. The companion BA addresses the
impacts to the federally listed Appalachian elktoe.
Wildlife
Several hundred little brown bats (1llyotis lucifugus) are known to exist in the Dillsboro
Powerhouse. The USFWS recommended that protection measures (e.g., bat box installation) will
be needed with removal of the powerhouse. This EA will address the effects of the alternatives
on these species and also discuss the protection treasures to be potentially implemented.
Cultural Resources
The EBCI identified that the Project alternatives and any subsequent drawdown exposure may
affect previously unknown cultural resources. Moreover, the NCS11130 reviewed the status of the
Dillsboro Powerhouse in relation to the National Register of Historic Places and has noted that
the property appears to be eligible in relation to the early history of hydroelectric generation in
western North Carolina. However, they further stated that they are not opposed to the removal of
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Duke Po%%er FINAL Dillsboro Environmental / Biolo;ical Assessment
the structures. This assessment will address the effects of the alternatives on these cultural
resources and also discuss the protection measures to be potentially implemented.
Other Resource Issues
Several other issues are also included in the discussion and analysis of this assessment (e.g.,
recreation and aesthetics).
Alternatives Associated with the Dillsboro Dam
The alternatives considered in this EA/BA for the Dillsboro Dam are limited to No Action, Partial
Removal, and Full Removal. In association with the future of the Dillsboro Powerhouse, the
alternatives include No Action, Closure, and Full Removal.
Alternative A (No Action) has been established as a benchmark against which the proposed
action of the Dillsboro Dam may be compared and evaluated from a current baseline.
Alternative A is associated with No Action or continued operation of the Project. This alternative
would essentially keep the Project and the dam in the present state of operation. This Project
generates a relatively small amount of electricity (912,330 kWh per year) and will continue to do
so under this alternative. The dam, as described below, will remain intact and in place and will
continue forming the Dillsboro Reservoir.
The Dillsboro Dam is a concrete masonry structure (cyclopean dam) that is approximately 310
feet in length and 12 feet high. Duke will continue to serve the same loads and service areas that
they now serve. They will continue to retain the benefits of low-cost hydroelectric generation for
the customers in the Nantallala service area.
With this No Action alternative, there would be no new major construction activities and the
current operations would continue through the existing and any future license articles and
conditions. Selection of this alternative would result in no change in the current environmental
conditions associated with the Project. As stated in the Final FERC license application associated
with the Project, the Project has no discernable effects on temperature or dissolved oxygen and is
in compliance and in support of all other applicable water quality standards and designated uses.
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Duke Poker FINAL Dillsboro Environmental / Biological Assessment
The Dillsboro Project has acted as sediment sink since completion of the dam. Although it is now
in a steady state since the reservoir has filled with sediment. Currently, an estimated 100,000
cubic yards of sediment is located upstream of the dam and consists of particles that are generally
less than 10 nun in size. Thickness of the deposits is estimated to be up to 12 feet near the dam
and decreases to zero at the upstream end (i.e., 0.8 miles upstream of the dam). If the No Action
alternative is pursued, existing sediment conditions of storage and transport will continue. The
storage and transport of sediment within and below the reservoir is assumed to be in equilibrium
with current conditions (i.e., inflow equals outflow) and will likely not change.
Based on recent fish sampling surveys (Duke 2003), there is some indication that the presence of
the dam may be a factor in the limited distribution or missing components of the fish fauna
upstream of the Project (e.g., darters and redhorse). Although some of these species may be
reduced due to geographic, gradient or other habitat parameters, the most obvious change in
species composition may be due to the restrictions of upstream movements due to the dam. There
is also a large population of listed Appalachian elktoe mussels immediately downstream of the
Project. This mussel population would continue to exist in its current state.
The NCSHPO has stated that there are no known archaeological sites located within the floodpool
or shoreline of the Project or likely to be found there. However, the NCSHPO stated that the
Dillsboro Powerhouse appears to be eligible for the National Register of Historic Places in
relation to the early history of hydroelectric generation in western North Carolina. However, they
further stated that they are not opposed to the removal of the structures. The adoption of this
alternative would result in no change in the floodpool elevations and shoreline areas within the
Project boundaries.
There are currently no developed recreation facilities such as boat launches or campsites within
the Project boundaries. Although the Town of Dillsboro maintains primary access areas on either
side of the Tuckasegce River downstream of the Project, use of the Project impoundment and
immediate tailrace for recreation is limited (i.e., fishing and boating). Although the existing
Project does provide very limited reservoir recreation such as fishing and boating, it will continue
to provide a barrier to free-flowing river types of recreation. There are no ongoing effects of
current Project operation on land use, aesthetics or socioeconomic resources.
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Duke Poiser FINAL Dillsboro Environmental / Biolobical Assessment
If Alternative A is pursued, fish passage and instream flow requirements at the other DPNA
Hydro Projects will have to be revisited per the TCST and the NCST Settlement Agreements and
that one likely result is a greater loss of electricity generation.
Alternative B (Partial Removal) is associated with the partial removal or breeching of the
existing Dillsboro Dam. With this alternative, the Project would cease to operate and no longer
generate electricity for Duke Power. For this alternative, the dam is first removed only to the
riverbed at the center to right side of the dam, to pass the low to normal river flow (looking
downstream). The remainder of dam is removed to approximately 4 to 5 ft. height, and is left in
place. High river flows will pass over this section.
Removal will be accomplished by use of hydraulic equipment to remove the dam in accordance
with a staged demolition plan. An excavator with a hoe-rain attachment will demolish the dam,
with an excavator and track loader used to remove sediment and remove the dam rubble and
concrete. During the demolition process, river flow will be, at various times and sometimes in
combination, diverted through the powerhouse, passed through a notch in the dam, and/or passed
over the partially demolished crest. Passing water through the sill gates is not an option since the
gates have been inoperable for some time. While the reservoir will be reduced in depth and
width, the partially removed dam will still impound water and it will not be an entirely free-
flowing waterbody.
At each stage of the demolition plan, sediment will be mobilized and transported to the river
below the dam. River flow will spread out and slow down after passing through the dam. As this
occurs, sediment will be deposited in the riverbed just below the dam and will be transported
downstream with the generated flows. See the sediment analysis associated with the Full
Removal Alternative.
A high flow event of approximately 667 cfs or greater is required in order to mobilize this
sediment. This flow is determined through discharge calculations associated with the East Fork
and West Fork Hydroelectric Projects. Therefore, it will be necessary for upstream dam
operators (Duke Power llydro Central) to release these flows at each stage of demolition to
accomplish this flushing of sediment below the dam. East Fork and West Fork hydro projects can
be used to provide 1,500 cfs flushing flow at Dillsboro Dam for three consecutive days. Flows
associated with the Dillsboro Project are influenced by releases from the most downstream West
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Duke Povier FINAL Dillsboro Environmental / Biological Assessment
Fork hydroelectric developments (i.e., Tuckasegee) and the most downstream East Fork
hydroelectric development (i.e., Cedar Cliff Lake). It is anticipated that for construction there will
be limited mechanical sediment removal on the left bank (looking downstream) immediately
upstream of the dam. This sediment will be removed by a backhoe or similar technique after it
has been drained by the drawdown. The quantity of sediment to be removed will be determined
during construction.
It is estimated that each removal stage will have duration of approximately two weeks through
initiation of demolition activities to a one-week, work stoppage period. From a stream flow,
environmental, and recreational perspective, it is desirable to perform the dam demolition work
during the higher flow mid-winter to early spring months.
The dam demolition project should commence in early January in order to perform the work
during the higher flow period (estimated 10-12 week phased duration). Work will be completed
by late March to early April.
This action would provide the benefit of resource enhancement and would at least partially
mitigate for the various impacts of the Dillsboro Dam and other Duke Power Nantahala Area
projects. Although the Project currently has little effect on water quality parameters and is in
compliance with the state standards, certain parameters such as dissolved oxygen and temperature
may slightly improve due to the reduction in impounded waters. Total suspended solids (TSS)
would, during the relatively short-term demolition period, increase. However, the majority of the
impounded sediments consist of coarser bedload sands and gravels. Furthermore, with this
alternative the Project will change from a sediment sink to a partial downstream sediment source.
A large portion of the existing accumulations of sediment would now be transported downstream
in pulses based on the generated flows.
Partial removal would also at least enhance the current aquatic resource distribution and species
richness of the upstream areas through limited upstream and downstream passage. The partial
removal of the dam would allow partial access by aquatic resources to an additional 9.5 miles of
river. The existing downstream-endangered mussel population will be temporarily but adversely
affected by increased sediment accumulation, subsequent changes in preferred substrate, and
changes in flow dynamics and will require mitigative measures (i.e., removal and relocation),
although upstream mussel populations would benefit by the increased passage of mussel host fish.
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
The adoption of this alternative may result in the exposure of archaeological resources due to the
lowering of the floodpool elevation and the subsequent exposure of littoral areas. The partial
removal of the dam could also provide almost a mile of additional riverine angling opportunity
for native fish and the delayed harvest managed trout fishery. The already limited reservoir
boating will be diminished; however, there would be increased opportunity for whitewater
boating and canoeing without the need of a portage around the dam.
There will be no changes in the existing land use although additional shoreline exposure would
benefit the riparian corridor through the formation of new wetlands and wider terrestrial buffers.
Aesthetic values of the Project would remain (i.e., water falling over the dam), however, it will be
diminished by the view of the partially removed dam structure remaining in the river. It is
assumed that socioeconomic values could increase slightly in association with the increased
opportunity for whitewater boating and riverine angling.
Alternative C (Full Removal) is associated with the full removal to existing grade of the
Dillsboro Dam. This is the preferred alternative for the future of the dam. With this alternative,
the Project would cease to operate and no longer generate electricity for Duke Power. For this
option, the dam is to be removed to the original riverbed over its full 310 ft. width. The river will
be returned to its assumed pre-darn bank-to-bank width and depth. Removal will be
accomplished by use of hydraulic equipment to remove the dam in accordance with a staged
demolition plan. An excavator with a hoe-ram attachment or similar mechanism will demolish
the dam, with an excavator and track loader used to remove sediment and remove the large
rubble/concrete. During the demolition process, river flow will be, at various times and
sometimes in combination, diverted through the powerhouse, passed through a notch in the dam,
and/or passed over the partially demolished crest. Passing water through the spill gates is not an
option since the gates have been inoperable for some time.
At each stage of the demolition plan, sediment will be mobilized and transported to the river
below the dam. River flow will spread out and slow down after passing through the dam. As this
occurs, sediment will be deposited in the riverbed just below the dam and will be transported
downstream with the generated flows over a period of 10-12 weeks. East Fork and West Fork
hydro projects can be used to provide 1500 cfs flushing flow at Dillsboro Dam for three
consecutive days. The project has the following sediment quantity, transport and downstream
deposition characteristics:
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Duke Power
FINAL Dillsboro Environmental / 6iolohical Assessment
1. The Dillsboro Dam has a watershed area of 290 square miles and an estimated mean annual
sediment yield of 54,100 tons (69,200 cubic yards) per year (USGS gauge data). Similar
river stretches such as the Little Tennessee River at Needmore, Nantahala River at Nantaliala,
and the Pigeon River at Hepco have estimated mean annual sediment yields of 110,000 tons
(90,909 cubic yards), 5,900 tons (4,876 cubic yards) and 65,000 tons (53,719 cubic yards),
respectively (USGS 1993).
2. Mean annual flow at Dillsboro Dam is 667 cfs. The 2-year flood is 5,527 cfs and the 10-year
flood equates to 10,868 cfs.
3. Based on bathymetric survey and subsequent analysis, the impoundment at Dillsboro Dam is
estimated to contain 100,000 cubic yards (121,500 tons) of sediment, consisting of fine to
coarse sand. The Dillsboro reservoir acts more as a low gradient alluvial channel than as a
lake.
4. Sediment load at Dillsboro Dam is estimated to be a minimum of 55,419 tons/year and a
maximum of 121,100 tons/year or average daily sediment load of 230 tons/day.
Conservatively, the estimated volume of stored sediment in the impoundment is equal to 1.0
to 2.2 years of mean annual watershed yield. Suspended sediment concentrations increase
rapidly as discharges rise and much of the annual load is conveyed during just a few days
with peak flows.
5. The reservoir has a low sediment trap efficiency due to its small size and short one-hour
(mean flow) detention period.
6. The U.S. Fish and Wildlife Service Tier 1 and Tier 2 evaluation of potential sediment
contaminants found no significant sediment quality concerns within the Project reservoir. No
sediment samples exceeded the Probable Effects Concentrations (PEC) and 81 percent of the
values were evaluated less than the Threshold Effects Concentrations (TEC). In evaluation of
the <20 percent sample that fell between the TECs and PECs for cadmium, chromium,
copper, nickel, and zinc, a geometric mean of the TECs and PECs was calculated and defined
as the "median effects concentration." One samples for nickel exceeded the MECs within the
reservoir and one sample exceeded downstream of the dam. Nickel has little affinity for
aquatic bioaccumulation, biomagnification, and mobilization in sediments. The
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Duke Power
F[1AL Dillsboro Environmental / Biological Assessment
concentrations found during the analysis are below the 10ug/I detection limit and are lower
than values toxic to very sensitive aquatic organisms.
7. With dam removal, no vertical channel incisement or headcuts are possible in this area due to
the bedrock controlled system. However, the river's submerged thalweg xvill widen as this is
the primary fluvial process.
3. Assessment of the channel stability within and through the impoundment indicates threshold
velocities will exceed critical levels and sediment scour is likely.
9. An analysis of the downstream channel indicates that it has a high sediment transport
capacity and sediments released from the dam site will be conveyed rapidly downstream with
little long-term deposition.
10. During a mean daily flow of 667 cfs, the sediment transport rate is 1,951 tons per day. The
net or available transport is 1,721 tons per day after subtracting the average daily yield of 230
tons per day. Based on the assumed first week load of 25 percent (30,375 tons), it would take
three weeks to transport it downstream. The subsequent release load over three months
would be an assumed 675 tons per day and is much less than the channel's mean net transport
load of 1,721 tons per day and should not accumulate. The two-year frequency flow of 5,827
cfs could convey the reservoir's entire volume of sediment in just two days. It is anticipated
that the sediment's released from the reservoir could form temporary downstream bars during
low flows, but would continue to move downstream and have little long-tenn impact. With a
two-year frequency flow approximately 7 miles and 14 downstream of the dam, it is expected
that all fine grain and sand size sediments will be carried through the reach without
deposition, except temporarily in pools and sheltered bank areas.
11. Critical reservoir banks near homes, utilities, and roads should be monitored and stabilized
with stone riprap or bioengineering techniques as needed.
A high flow event of approximately 667 cfs or greater is required in order to mobilize this
sediment. This flow is determined through discharge calculations associated with the East Fork
and West Fork hydroelectric projects. Therefore, it will be necessary for upstream dam operators
(Duke Power Hydro Central) to release these flows at each stage of demolition to accomplish this
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Duke Poi,er FINAL Dillsboro Environmental / Biological Assessment
flushing of sediment below the dam. Flows associated with the Dillsboro Project are influenced
by releases from the most downstream West Fork hydroelectric development (i.e., Tuckasegee)
and from the most downstream East Fork hydroelectric development (i.e., Cedar Cliff Lake).
East Fork and West Fork hydro projects can be used to provide 1,500 cfs flushing flow at
Dillsboro Dam for three consecutive days during the demolition period.. It is anticipated that
there will be limited mechanical sediment removal on the left bank (looking downstream)
immediately upstream of the dam in association with construction activities. This sediment will
be removed by a backhoe or similar technique after it has been drained by the drawdown. The
quantity of sediment to be removed has not been determined.
It is estimated that each stage will have duration of approximately two weeks through initiation of
demolition activities to a one-week, work stoppage period. From a stream flow, environmental,
and recreational perspective, it is desirable to perform the dam demolition work during the
planned high operational flow during the mid-winter to early spring months. The dam demolition
project should commence in early January in order to perform the work during the higher flow
period (estimated 10-12 week phased duration). Work will be completed by late March to early
April.
An environmental monitoring plan (i.e., pre-removal, removal, and post-removal) will be
prepared in consultation with the resource agencies such the NCWRC, USFWS, NCDWQ,
NCDWR, and ECBI) before execution of the full removal. It is anticipated that Duke will meet
with the pertinent agencies and other interested parties via a technical conference to identify any
resource and safety issues prior to the removal.
This action would provide the full benefit of resource enhancement and would mitigate for the
various impacts of the Dillsboro Dam and other DPNA Hydro Projects. Although the Project
currently has little effect on water quality parameters and is in compliance with the state
standards, certain parameters such as dissolved oxygen and temperature may slightly improve due
to the reduction in impounded waters. Total suspended solids (TSS) would, during the relatively
short-term (estimated 10-12 week) demolition period, increase. However, the majority of the
impounded sediments consist of coarser bedload sands and gravels. Furthermore, with this
alternative the Project will change from a sediment sink to a downstream sediment source.
Through staged or phased removal over a specific period, all or most of the existing
accumulations of sediment would be transported downstream.
ES-12
Duke Po%%er FINAL Dillsboro Environmental / Biological Assessment
Full removal would enhance the current aquatic resource distribution and species richness of the
upstream areas through complete upstream and downstream passage. The removal of the dam
would allow full access by aquatic resources to 9.5 miles of additional river. The existing
downstream-endangered mussel population will be temporarily but adversely affected by
increased sediment accumulation, subsequent changes in preferred substrate, and changes in flow
dynamics and will require mitigative measures (i.e., removal and relocation). However, mussel
host fish species will now have complete passage upstream and downstream.
The adoption of this alternative may result in the exposure of archaeological resources due to the
lowering of the floodpool elevation and the subsequent exposure of littoral areas. The removal of
the dam could also provide almost a mile of additional riverine angling opportunity for native fish
and the delayed harvest managed trout fishery. The riverine stretch will now be unsuitable for
reservoir boating, however, there would be increased opportunity for whitewater boating and
canoeing without the need of a portage around the dam.
There will be no changes in the existing land use although additional shoreline exposure would
benefit the riparian corridor through the formation of new wetlands and wider terrestrial buffers.
Natural aesthetic values of the Project would be enhanced by the view of the free flowing stretch
of river. It is assumed that socioeconomic values would increase slightly in association with the
increased opportunity for whitewater boating and riverine angling.
Alternatives Associated with the Dillsboro Powerhouse
Alternative A (No Action) has been established as a benchmark against which the proposed
action of the Dillsboro Powerhouse may be compared and evaluated from a current baseline.
This alternative is associated with No Action or continued operation of the Project. This
alternative would essentially keep the Project and the associated powerhouse in the present state
of operation. This project generates a relatively small amount of electricity (912,330 kWh per
year) and will continue to do so under this alternative. The powerhouse, as described below, will
remain intact and in place and will continue generating energy through use of the Dillsboro
Reservoir.
ES-13
Duke Posner FINAL Dillsboro Environmental / Biolohical Assessment
With this No Action alternative, there would be no new major construction activities and the
current operations and maintenance would continue through the existing and any future license
articles and conditions.
Based on an environmental site assessment of the powerhouse in 2002, no major potential sources
of environmental contamination were identified. There are minor concerns associated with lead-
based paint on the structure and asbestos on the generator/turbine wiring. Although a minor
concern, the level of potential risk was deemed low with no action recommended during
continued operation.
Based on cultural resource surveys conducted by Duke Power, the Project lacks sufficient integrity
to meet National Register of Historic Places (NRIIP) criteria. Although the original powerhouse
and dam were built in 1913, both were extensively modified in 1958. The NCSHPO reviewed the
status of the Dillsboro Powerhouse in relation to the National Register of Historic Places and has
noted that the property appears to be eligible in relation to the early history of hydroelectric
generation in western North Carolina. However, they further stated that they are not opposed to
the removal of the structures.
With Alternative B (Closure), the powerhouse would be left in place with very limited public
access. The entrance of the structure would be locked and a kiosk would be established that
describes the history of the Project and powerhouse and its past importance to the Nantahala
Area. With this alternative, the Project would cease to operate and no longer generate electricity
for Duke Power.
Potentially hazardous items (e.g., asbestos) and oil and lubricants are to be removed prior to
closure. NCSHPO suggests that the powerhouse may be important in the context of the history of
electric power development in the Nantahala Area. Duke will conduct further discussions with
the NCSHPO to resolve this issue.
The estimated 500 little brown bats would still use the powerhouse as roosting habitat. No other
principal environmental effects are associated with closure of the powerhouse.
The powerhouse closure plan can be implemented at an estimated cost of 53,000.
ES-14
Duke Poi%er FINAL Dillsboro Environmental / Biological Assessment
With Alternative C (Demolition), the pokverliouse is to be completely demolished down to the
foundation. This is the preferred option for the future of the powerhouse. With this alternative,
the Project would cease to operate and no longer generate electricity for Duke Power. Potentially
hazardous items (e.g., asbestos) and oil and lubricants arc to be removed prior to commencing the
demolition work. Equipment is assumed to have no salvage value to the Owner. The
superstructure is to be demolished and removed from site. The concrete substructure walls and
floors are to be demolished and removed from site. At completion of demolition, the pits and
holes will be filled to a degree that there will be no safety hazards left on site. The final surface
will be armored and/or vegetated to remain stable during high water events. The powerhouse
demolition plan can be implemented at an estimated cost of 5200,000.
The NCSHPO reviewed the status of the Dillsboro Powerhouse in relation to the National
Register of I listoric Places and has noted that the property appears to be eligible in relation to the
early history of hydroelectric generation in western North Carolina. However, they further stated
that they are not opposed to the removal of the structures. Duke will conduct further discussions
with the NCSIIPO in association with this issue.
With the demolition of the powerhouse, the estimated 500 little brown bats would lose their
roosting habitat. A mitigation plan will be developed that incorporates measures to benefit the
bat population including the installation of bat boxes. No other principal environmental effects
are associated with removal of the powerhouse.
ES-IS
Duke Po%%cr FINAL Dillsboro EnNironniental / Biological Assessment
1.0 PURPOSE AND NEED
1.1 Purpose for Taking Action
Duke Powcr, division of Duke Energy Corporation (Duke) has prepared this Final Environmental
Assessment (EA) in accordance with the procedures for implementation of the National
Environmental Policy Act (NEPA) through the U.S. Fish and Wildlife Service (USFWS) as stated
by the Council of Environmental Quality (USFWS undated). The purpose of this EA is to
disclose, identify, evaluate, and determine the actions that may be taken by Duke, the supporting
federal and state agencies, and other stakeholders in determining the future of the existing
Dillsboro Dam. The assessment describes and evaluates alternatives to the proposed course of
action. Duke will use the results of this assessment as an objective decision-making tool in
addressing the future of the Dillsboro Dam and Powerhouse.
In association with this EA, is a companion Biological Assessment (BA) to determine what extent
the above-mentioned actions may have on the federally listed Appalachian elktoe mussel
(Alasmidonta raveneiiana). This biological assessment is prepared in accordance with legal
requirements set forth under Section 7 of the Endangered Species Act (16 U.S.C 1536 (c)), and
follows the procedures and recommendations established through the USFWS's NEPA guidance
and ESA guidance. The general format of the BA is flexible so that it can be incorporated into an
EA or EIS document, as in this case (FERC 2001). Attachment A provides guidance to the BA
reviewer as far as where in this EA the various pertinent BA sections are located.
Need for,raking Action
The Dillsboro Project is located on the Tuckasegee River near the Town of Dillsboro in Jackson
County, North Carolina (Figure 3.1-1). Duke operates this hydroelectric project under a license
from the Federal Energy Regulatory Commission (FERC) (FERC Project No. 2602). This
existing license expires in 2005, and the process of obtaining a subsequent license officially
began in 2000 with Duke's release of the First Stage Consultation Document.
In pursuit of the subsequent Dillsboro license, Duke opted to pursue an enhanced Traditional
Licensing Process to gather meaningful and significant input from stakeholders on Project
operations and resource protection and enhance?nent (Duke Power 2003). In late 2000, in an
effort to identify issues and stakeholder interests in the Tuckasegee watershed, as well as the
upstream East Fork and West Fork watersheds, the Tuckasegee Cooperative Stakeholder Team
(TCST) was assembled. The TCST consists of stakeholders who represent various interests and
Duke Po%%cr FINAL Dillsboro Environmental / Biological Assessment
uses of the waters and related natural resources of the Tuckasegee River Basin upstream of
Bryson City. Included on the TCST are representatives of state and federal resource agcncies,
local governments, adjacent landowners, resource users, basin-wide conservation organizations,
and Duke Power. The purpose of the TCST was to identify issues and interests related to the
hydropower projects on the Tuckasegee River and their operations, and using information derived
from the relicensing studies and other sources, develop a non-binding Consensus Agreement and
a subsequent binding Settlement Agreement (Duke Power 2003).
The TCST Settlement Agreement (Agreement), which was signed by the authorized members in
late October 2003, includes a Multi-Project Resource Enhancement measure of the potential
removal of Dillsboro Dam and Powerhouse. As stated in the Agreement "...tile parties
acknowledge that Duke Power worked with the USFWS, North Carolina Division of Water
Resources (NCDWR), North Carolina Division of Water Quality (NCDWQ), North Carolina
Wildlife Resources Commission (NCWRC), the North Carolina State Historic Preservation
Office (NCSIII'O) and the Eastern Band of Cherokee Indians (EBCI) and complete(d) the
necessary environmental, cultural resource, and engineering assessments regarding the removal of
Dillsboro Dam and potentially the Dillsboro Powerhouse. These assessments evaluate(d) the
potential effects of dam removal on aquatic species; determined the extent of any cultural
resources impacts, and considered the options of removing the powerhouse." Therefore the need
for taking action on this Project is directed towards providing and satisfying the important
resource enhancement initiative that will mitigate for the various impacts of the DPNA Hydro
Projects, as described in the Agreement. The removal of Dillsboro Dam would provide
mitigation for fish passage and instream flow requirements in bypassed stream reaches on other
DPNA Hydro Area Projects.
The settlement agreement prepared and signed by the TCST, as well as the settlement agreement
prepared and signed by the Nantahala Cooperative Stakeholder Team (NCST), was filed with the
FERC in early January 2004. It was noted to the FERC that removal of the Dillsboro Project's
dam is a key component of the settlement agreements (i.e., significant gains in aquatic habitat in
the Tuckasegee River) and that Duke Power is preparing a Dillsboro Project License Surrender
Application, that includes decommissioning of the powerhouse and the removal of Dillsboro
Dam, for filing with the Commission by June 1, 2004. This EA/BA is an important component of
the Dillsboro License Surrender Application.
l-2
Duke Poiser FINAL Dillsboro Emironmcntal / Biological Assessment
Identify the Decision to be made by the Responsible Official
Duke Power and the various TCST parties, including the agencies listed below, have used the
results of this assessment to identify and select the best overall alternative associated with the
future of the Dillsboro Dam and Powerhouse.
Identify Issues Raised During Project Planning and Scopin;
Public and stakeholder participation in determining the scope of this EA/BA essentially began in
2000 in an effort to identify issues and stakeholder interests within the Tuckasegee watershed.
This effort was directly related and in parallel to the preparation and submission (July 2003) of
the Final FERC License Application for the Dillsboro Project.
Based on progress in association with the above-mentioned Settlement Agreement, an initial
scoping meeting was conducted in which the preliminary details and proposed outline ol' the
EA/BA were described to the TCST stakeholders. Representatives attending this initial scoping
meeting included:
• U.S Fish and Wildlife Service (USFWS);
• Natural Resources Conservation Service (NRCS);
• U.S. Forest Service (USFS);
¦ Eastern Band of Cherokee Indians (EBCI);
¦ North Carolina Wildlife Resources Commission (NCWRC);
¦ North Carolina Division of Water Resources (NCDWR);
¦ North Carolina Division of Water Quality (NCDWQ);
• Duke Power
Subsequent discussions and meetings included Town of Dillsboro officials, the Tennessee Valley
Authority (TVA) and the U.S. Army Corps of Engineers (Corps).
In addition to this and several other issue update meetings, consultation letters (requests for
information) were sent to the above stakeholders and several local governments (e.g., Town of
Dillsboro). Responses from these stakeholders, as well as the verbal comments from tile scoping
and update meetings were used to develop this document and address the major issues
(Attachment B). A draft version of the EA/BA was submitted to the agencies and interested
stakeholders on September 15, 2003 for review and comment. Agency and stakeholder
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Duke Po%%cr FINAL Dillsboro En-ironmental / Biological Assessment
continents and recommendations associated with the draft document were compiled and
incorporated into this final version. These comments are found in Attachment B of this
document.
Based on both internal discussions and stakeholder discussions and the nature of the Project,
several issues were identified that will require detailed evaluation and are important in the
decision-making analysis in comparison of the alternatives. These issues are as follows:
Sediment Quantity and Quality
The stakeholders have identified that sediment accumulation in the Dillsboro Project is an area of
primary concern. Discussions and analysis concerning this issue focus on the estimated quantity
of existing sediment affected by the alternatives; quality (i.e., contamination) of existing
sediments; mobilization/transport of existing sediments; potential downstream sediment transport,
assimilation and distribution associated with the alternatives and any impacts; and any sediment
management techniques to be employed with the alternatives. Due to the importance of
accumulated sediment within the Project and the potential for impacts, project specific studies
were conducted to determine the level of any sediment contamination, as well as sediment
quantities, downstream transport and deposition.
Aquatic Life
The stakeholders also identified that the alternatives may affect the abundance, types, and
movement/passage of aquatic life both upstream and downstream of the existing dam. EA
discussion and analysis addresses the existing conditions associated with the fishery and benthic
macroinvertebrate resources and the potential effects to them from each of the alternatives.
Rare, Threatened, and Endangered (RTE) Species
The scoping process for this Project and the subsequent field studies has identified two RTE
mussel species and their critical habitats immediately downstream of the Dillsboro Dam. These
species include the Appalachian elktoe (Alasmidonta raveneliana) (federal and state endangered)
and the wavy-rayed lampmussel (Lampsilis fasciola) (NC Species of Concern). Two fish species,
the wounded darter (Etheostana vulneratum) and the olive darter (Percina squamata), both NC
Species of Concern, are also found immediately downstream of the Project. The only other RTE
species found within the Project is the aquatic salamander the Eastern lleilbender (federal and NC
Species of Concern). This EA is required to address the effects of the alternatives on these
14
Duke PoiNcr
FINAL Dillsboro En%ironmcntal / Biological Assessment
species and also discuss the protection measures to be potentially implemented. The companion
BA addresses the impacts to the federally listed Appalachian elktoe as requested by the USFWS.
Wildlife
Approximately 500 little brown bats (Afyotis lucifiq us) are known to exist in the Dillsboro
Powerhouse (see photograph in Attachment Q. The USFWS recommended that protection
measures (e.g., bat box installation) might potentially be needed if the powerhouse removal or
refurbishment alternative is selected. This EA will address the effects of the alternatives on these
species and also discuss the protection measures to be potentially implemented.
Cultural Resources
The EBCI identified that the Project alternatives and any subsequent drawdown exposure may
affect previously unknown cultural resources. Moreover, the NCSHPO reviewed the status of the
Dillsboro Powerhouse in relation to the National Register of Historic Places and has noted that
the property appears to be eligible in relation to the early history of hydroelectric generation in
western North Carolina. However, they further stated that they are not opposed to the removal of
the structures. This assessment will address the effects of the alternatives on these cultural
resources and also discuss the protection measures to be potentially implemented.
Other Resource Issues
Several other issues are also included in the discussion and analysis of this assessment (e.g.,
recreation, socioeconomics and aesthetics).
1-5
Duke Power FINAL Dillsboro Environmental / Biological Assessment
2.0 ALTERNATIVES INCLUDING THE PROPOSED ACTION
This section of the assessment describes the various courses of action and alternatives that could
satisfy the above-mentioned purpose and need. The alternatives considered in this document for
the Dillsboro Dam are limited to No Action, Partial Removal, and Full Removal. In association
with the future of the Dillsboro Powerhouse, the alternatives are No Action, Closure, and Full
Removal. This section provides a description of each alternative and a comparison to each
alternative. A discussion of the potential effects for each alternative is provided in Section 4.0.
The No Action alternative will be discussed first since this allows the reviewer to fully determine
the baseline against which the action alternatives are analyzed.
2.1 Alternatives for the Dillsboro Dam
2.1.1 Alternative A - No Action
Alternative A has been established as a benchmark against which the proposed action of the
Dillsboro Dam may be compared and evaluated from a current baseline.
Alternative A is associated with No Action or continued operation of the Project. This alternative
would essentially keep the Project and the dam in the present state of operation. This Project
generates a relatively small amount of electricity (912,330 kWh per year) and will continue to do
so under this alternative. The dam, as described below, will remain intact and in place and will
continue forming the Dillsboro Reservoir.
The Dillsboro Dam is a concrete masonry structure (i.e., cyclopean dam) that is approximately
310 feet in length and 12 feet high (Figure 2.1-1 and 2.1-2). Major components of the Dillsboro
Dam are described in Section 3.0. Duke will continue to serve the same loads and service areas
that they now serve. They will continue to retain the benefits of low-cost hydroelectric
generation for the customers in the Nantahala service area. If the dam stays in place, fish passage
and instream flows will have to be renegotiated in the two Settlement Agreements and will likely
result in a net greater loss of hydropower production.
With this No Action alternative, there would be no new major construction activities and the
current operations would continue through the existing and any subsequent license articles and
conditions. As stated in the Final FERC license application associated with the Dillsboro Project,
the Project has no discernable effects on temperature or dissolved oxygen and is in compliance
and in support of all other applicable water quality standards and designated uses.
2-l
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Duke Poi%cr FINAL Dillsboro Environmental / Biological Assessment
The Dillsboro Project has acted as sediment sink since completion of the dam. The Project is
now in a steady state or equilibrium since the reservoir has filled with sediment. Currently, an
estimated 100,000 cubic yards of sediment is located upstream of the dam and consists of
particles that are generally less than 10 mm in size. If the No Action alternative is pursued,
existing sediment conditions of storage and transport will continue. The storage and transport of
sediment within and below the reservoir is assumed to be in equilibrium with current conditions
and will likely not change.
Based on recent fish sampling surveys (Duke Power 2003), there is some indication that the
presence of the dam may be a factor in the limited distribution or missing components of the fish
fauna upstream of the Project (e.g., darters). Although some of these species may be reduced due
to geographic, gradient or other habitat parameters, the most obvious change in species
composition may be due to the restrictions of upstream movements due to the dam. There is also
a large population of listed Appalachian elktoe mussels immediately downstream of the Project.
This mussel population would continue to exist in its current state.
The NCSHPO has stated that there are no known archaeological sites located within the floodpool
or shoreline of the Project or likely to be found there.
There are currently no developed recreation facilities such as boat launches or campsites within
the Project boundaries. Although the Town of Dillsboro maintains primary access areas on either
side of the Tuckasegee River downstream of the Project, use of the Project impoundment and
immediate tailrace for recreation is limited (i.e., fishing and boating).
2.1.2 Alternative B - Partial Removal
Alternative B is associated with the partial removal or breeching of the existing Dillsboro Dam.
With this alternative, the Project would cease to operate and no longer generate electricity for
Duke Power. For this alternative, the dam is to be removed to the riverbed at the center to right
side of the dam, to pass the low to normal river flow. The remainder of the dam is removed to
approximately 4 to 5 ft. height, and is left in place. High river flows will pass over this section.
At each stage of the demolition plan, sediment will be mobilized and transported to the river
below the dam. River flow will spread out and slow down after passing through the dam. As this
occurs, sediment will be deposited in the riverbed just below the dam. A high flow event is
24
Duke Poorer
FINAL Dillsboro Emironmental 1 Biological Assessment
required in order to flusli this sediment downstream. "Therefore, it will be necessary for upstream
dam operators (Duke Power Hydro Central) to release water at each stage of demolition to
accomplish this flushing of sediment below the dam (Table 2.1-1). The flows required to
mobilize the sediment will be 667 cfs or greater (Milone and MacBroom 2004).
This.action would provide the benefit of resource enliancement and would at least partially
mitigate for the various impacts of the Dillsboro Dam and other DPNA I Iydro Projects (see "Table
4.2-1).
Table 2.1-1. Operational flogs provided by the upstream Duke Projects in association with sediment
removal.
illcan Flow
.I,VV FEB A1AR APR
Hydro Plant (cfs) (cfs) cfs) (cfs)

Tanasee Creek/Wolf Creek 157 181 209 185
Bear Creek 284 328 379 334
Cedar Cliff 301 347 401 354
Thorpe 148 170 190 166
East Fork and West Fork hydro projects can be used to provide 1500 cfs flushing Clow at
Dillsboro Dam for three consecutive days

.JAN FEB 11AIZ APIZ
cfs (cfs) cfs) cfs)
Tuckasegee River at Dillsboro Dam
without turbine discharges from East 503 586 678 591
Fork and West Fork hydro, plants
Thorpe Hydro maximum turbine

discharge 250 250 250 250
Cedar Cliff I lydro maximum turbine

discharge 480 480 480 480
Bear Creek spill from dam into Cedar

Cliff Lake 100
Cedar Cliff spill from Cedar Cliff

Dam 267 184 92 179

Total flushing flow at Dillsboro Darn 1500 1500 1500 1500
Maximum drawdown caused by spilling and generating continuously at maximum load for 72 hours
Bear Creek Lake
Minimum
Normal Elevation after Normal Target Normal
Minimum providing 72 Elevation (ft) Maximum
Elevation (ft) hours of flows Elevation (ft)
(ft)
January 91.0 89.8 93.0 98.0
February 91.0 91.5 93.0 98.0
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Duke Po%%er
FINAL Dillsboro Environmental / Biological Assessment
March 91.0 91.8 93.0 98.0
April 92.0 93.8 95.0 98.0
Normal Full Pond Elevation = 100.0 ft.
Cedar Cliff Lake
Minimum
Normal Elevation after Normal Target Normal
Minimum providing 72 Elevation (ft) Maximum
Elevation (ft) hours of flows Elevation (ft)
(ft)
Januarv 96.0 89.8 98.0 100.0
February 96.0 89.3 98.0 100.0
March 96.0 93.8 98.0 100.0
April 96.0 89.3 98.0 100.0
Normal Full Pond Elevation = 100.0 ft.
Lake Glenville
Minimum
Normal Elevation after Normal Target Normal
Minimum providing 72 Elevation (ft) Maximum
Elevation (ft) hours of flows Elevation (ft)
(ft)
January 85.0 89.5 90.0 94.0
February 85.0 89.8 90.0 94.0
March 88.0 90.8 91.0 94.0
April 90.0 92.8 93.0 96.0
Normal run vono tievation = iou.u tt.
2.1.2.1 EnLineeritlf_,Ana1vsis
For this option, the dam is to be removed to the riverbed at the center to right side of the dam, to
pass the low to normal river flow. The remainder of the dam is removed to approximately 4 to 5
ft. height, and is left in place. High river flows will pass over this section.
Removal will be accomplished by use of hydraulic equipment to remove the dam in accordance
with a staged demolition plan. An excavator with a hoe-ram will demolish the dam, with an
excavator and track loader used to remove sediment and remove rubble/concrete. Standard oil
booms will be installed downstream of the dam prior to drawdown for additional stream
protection. During the demolition process, river flow will be, at various times and sometimes in
combination, diverted through the powerhouse, passed through a notch in the dam, and/or passed
over the partially demolished crest.
At each stage of the demolition plan, sediment will be mobilized and transported to the river
below the dam. River flow will spread out and slow down after passing through the dam. As this
occurs, sediment will be deposited in the riverbed just below the dam. A high flow event of
2-6
Duke Po%Ner FINAL Dillsboro Environmental / Biological Assessment
approximately 667 cfs or greater cfs is required in order to mobilize this sediment (111acBroom
and Milone 2004). Therefore, it will be necessary for upstream dam operators (Duke Power
Hydro Central) to release water at each stage of demolition to accomplish this flushing of
sediment below the dam (Table 2.1-1). East Fork and West Fork hydro projects can be used to
provide 1,500 cis flushing flow at Dillsboro Dam for three consecutive days.
The river will flow through a relatively narrow channel within the existing sediment deposits
during the dam demolition process and shortly thereafter. It is anticipated that after completion of
dam demolition, the river will not return to its pre-dam bank-to-bank width and depth with a
partial dam in place.
The estimated duration of dam demolition field work is 10 to 12 weeks, not including work in the
powerhouse and at the powerhouse forebay and tailrace. This demolition will take place between
early January and early April in an effort to take advantage of planned high operational flows and
avoid the primary boating and angling seasons
A Section 401 (Clean Water Act) Water Quality Certification will be required from tile NCDWQ.
A Section 404 "dredge and fill" permit will also be required for this work within the "waters of
the U.S." This project will most likely require an Individual Permit due to the scope (e.g.,
endangered species presence, magnitude of work within the river, work within possible navigable
waterway) and importance of the removal project.
An environmental monitoring plan (i.e., pre-removal, removal, and post-removal) will be
prepared in consultation with the resource agencies such as the NCWRC, USFWS, NCDWQ,
NCDWR, and ECBI before execution of the partial removal. This monitoring would be similar to
that provided for the following full dam removal alternative.
DAM REMOVAL (PARTIAL,) PLAN
The crest of the 12-foot high dam is at elevation 1972.0 ft. The dam is 310 ft. wide, including a
34-foot wide gate and overflow spillway structure at the left (facing downstream) abutment of the
dam.
From a stream flow, environmental, and recreational perspective, it is desirable to perform the
dam demolition work during the planned high operational flows mid-winter to early spring
2-7
Duke Posscr
FINAL Dillsboro Environmental / Biological Assessment
months (Table 2.1-1). Stream flow is higher during the summer months due to minimum flow
requirements for angling and boating. The target river flow rate during angling season (.April I"
through the first week of June and Labor Day weekend through the last week of October) is 500
cfs. 'File target river flow rate during boating season (first weekend of June through Labor Day
weekend) is 800 cfs.
The dam demolition project should commence in early January in order to perform the work
during the planned high operational flow period. Work will be completed by late March to early
April.
The partial removal plan is as follows:
¦ Excavate and remove existing sediment in the forebay area immediately upstream of the
trash racks. Remove or disperse the left training wall in the tailrace to reduce water
velocity and the potential for right bank erosion. These banks will quickly re-vegetate upon
project completion both naturally and with the supplemental herbaceous plantings.
¦ For both units 1 and 2, disconnect the turbine shaft from the generator shaft and lock the
turbine shaft to prevent turbine runner rotation. Open units 1 and 2 head gates and turbine
wicket gates. Open the pad gate on the unit 3 head gate. At full pond, approximately 400
to 500 cfs will flow through the powerhouse in this manner. It may be beneficial to use the
hoc-ram to demolish the entire head gate at unit 3 of the powerhouse to increase flow
through that unit. Maintain erosion protection of the bank adjacent to the forebay and in
the tailrace due to possible additional scouring.
¦ To the extent possible, upstream dam operators (Duke Power) will limit river flow at the
Dillsboro Dam during the 1 st phase of dam demolition (excavation of the initial notch in
the dam).
¦ Draw down the pond to the extent possible via flow through the powerhouse.
¦ Standard oil booms will be installed downstream of the dam prior to drawdown for
additional stream protection. Use the excavator with hoe-ram on the downstream side of
the darn to demolish a 6 to 8 ft. deep by approximately 40 to 60 ft. wide notch in the right
abutment of the dam adjacent to the powerhouse. In conjunction with flow through the
powerhouse, this notch is to pass the full river flow during the staged demolition process.
¦ floc-ram (or similar mechanism) excavation is most efficiently performed when the
equipment is above the work. As such, the excavator with hoe-ram will work from the
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Duke Poiwr
FINAL Dillsboro Environmental / Biological Assessment
upstream side of the dam. This will be accomplished by creating a narrow working pad in
the reservoir adjacent to the upstream face of the dam. Place temporary 12-inch rock as
needed just upstream of the dam from the left side of the pond out to approximately 150 ft.
from the left abutment. Rock can be placed directly into sediment on the upstream side of
the dam. This will create the working pad for the excavator with hoe-ram to access the
dam from the upstream side. The top of the pad will be placed to slightly below the water
level. Working from the end of this pad, the excavator will reach the left edge of the notch.
Starting at that point, the hoe-ram will excavate the dam in horizontal 3 to 4 ft. lifts. The
excavator will lower the working pad as the work progresses towards the left abutment of
the dam. In this way, the dam will be excavated to its base over the 310 ft. required width,
and to a height of 3 to 4 ft. elsewhere. The working pad will be fully removed at
completion of dam demolition.
• As the dam is removed to its base, the river will spread out from the initial notch and begin
to flow over the mostly demolished dam. As the dam is lowered to 2 to 3 ft. in height, the
excavator can enter the river to excavate the remaining concrete, including the bottom of
the initial notch.
¦ At the completion of the initial notch excavation, and again at completion of excavation of
each 3 to 4 ft. stage, demolition activity will be paused in order to create a deliberate high
flow event. East Fork and West Fork hydro projects can be used to provide 1500 cfs
flushing flow at Dillsboro Dam for three consecutive days. There should be no more than
four of these pauses, and duration of each pause should not exceed one week by releasing
water from upstream Tuckasegee projects.
¦ No in-stream fish habitat enhancement structures or similar measures (e.g., revetments,
rock veins) will be installed with this alternative.
COST
The above demolition plan can be implemented at an estimated cost of 5260,000. This cost
assumes that the project can be implemented as described herein.
2.1.3 Alternative C - Full Removal
Alternative C is associated with the full removal to grade of the existing Dillsboro Dam and
Powerhouse. This is the preferred alternative associated with the future of the dam. With this
alternative, the Project would cease to operate and no longer generate electricity for Duke Power.
For this option, the dam is to be removed to the original riverbed over the full width of the river
(Figure 2.1-3). The river will be returned to its assumed pre-dam bank-to-bank width and depth.
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Duke Poi%cr FINAL Dillsboro Environmental! Biological Assessment
Removal will be accomplished by use of hydraulic equipment to remove the dam in accordance
with a staged demolition plan. An excavator with a hoe-ram attachment or similar mechanism
will demolish the dam, with an excavator and track loader used to remove sediment, if necessary,
and remove rubble/concrete. During the demolition process, river flow will be, at various times
and sometimes in combination, diverted through the powerhouse, passed through a notch in the
dam, and/or passed over the partially demolished crest. At each stage of the demolition plan,
sediment will be mobilized and transported to the river below the dam. Some mechanical
sediment removal is anticipated upstream of the dam along the left bank.
This action will provide the full benefit of resource enhancement and mitigate for the various
impacts of the Dillsboro Dam and other DPNA Hydro Projects, as stated in the Settlement
Agreement (see Table 4.2-1).
2.1.3.1 Engineering Ana1ysis
For this option, the dam is to be removed to the original riverbed over the full width of the river.
The river will be returned to its assumed pre-dam bank-to-bank width and depth. Removal will
be accomplished by use of hydraulic equipment to remove the dam in accordance with a staged
demolition plan. An excavator with a hoe-ram attachment or similar mechanism will demolish
the dam, with an excavator and track loader used to remove sediment, if necessary, and remove
rubble/concrete.
Standard oil booms will be installed downstream of the dam prior to drawdown for additional
stream protection. During the demolition process, river flow will be, at various times and
sometimes in combination, diverted through the powerhouse, passed through a notch in the dam,
and/or passed over the partially demolished crest.
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Duke Power
FINAL Dilisboro Environmental / Biological Assessment
Figure 2.1-3 Dillsboro Dam Removal Sequence (1 of 2)
Powerhouse
Gate
0 00 0 Dam / Spillway Structure
1) Place access ramp, pre-demolition activities, start pre-removal monitoring
2) Remove powerhouse superstructure, initiate removal phase monitoring
3) Remove initial dam section, 40 - 60 R.
4) Sequential Removal
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Duke Power
FINAL Dillsboro Environmental / Biological Assessment
Figure 2.1-3 Dillsboro Dam Removal Sequence (coat).
Powerhouse
Gate
Dam / Spillway Structure
5) Continue sequential removal and flow control
G) Continue removal working to left bank
7) Dam removal completed to left bank
8) Remove Powerhouse substructure, post-removal monitoring
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Duke Power
FINAL Dillsboro Environmental / Biological Assessment
Figure 2.1-4 Dillsboro Dam Removal Sequence
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-r
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Duke Powcr FINAL Dillsboro Environmental / Biological Assessment
At each stage of the demolition plan, sediment will be mobilized and transported to the river
below the dam. River flow will spread out and slow down after passing through the dam. As this
occurs, sediment will be deposited in the riverbed just below the dam. A flow event of
approximately 667 cfs or greater is required in order to mobilize sediment. Therefore, it will be
necessary for upstream dam operators (Duke Power Hydro Central) to release water from the
upstream East Fork and Nest Fork projects at each stage of demolition to accomplish this
flushing of sediment below the dam. East Fork and West Fork hydro projects can be used to
provide 1,500 cfs flushing flow at Dillsboro Dam for three consecutive days (Table 2.1.1). It is
anticipated that some mechanical sediment removal will be conducted upstream of the dam along
the left bank (looking downstream). This removal will be accomplished through use of a backhoe
or similar technique when the sediment has been drained from the drawdown. The quantity of
sediment to be removed has not been detennined.
The river will flow through a relatively narrow channel within the existing sediment deposits
during the dam demolition process and shortly thereafter. It is anticipated that after completion of
dam demolition, the river will return to its pre-dam bank-to-bank width and depth. The estimated
duration of dam demolition field work is 10 to 12 weeks, not including work in the powerhouse
and at the powerhouse forebay and tailrace.
A Section 401 (Clean Water Act) Water Quality Certification will be required from the NCDWQ.
A Section 404 "dredge and fill" permit will also be required for this work within the "waters of
the U.S." This project will most likely require an Individual Permit due to the scope (e.g.,
presence of endangered species, magnitude of work within the river, work within possible
navigable waterway) and importance of the removal project.
SEDINTENT MANAGEMENT PLAN
The primary focus of the sediment management plan will be to control sediment erosion and
transport below the dam during the demolition process. The plan will promote natural and phased
river sediment transport from the existing sediment deposits upstream of the dam to the river
downstream of the dam. This will be accomplished over the course of the demolition period
during high flow and natural high water events. Some mechanical sediment removal is
anticipated upstream of the dam on the left bank. Sediment will be managed during the project
primarily by:
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Duke Poi%er
FINAL Dillsboro Environmental / Biological Assessment
DANT REMOVAL PLAN
The crest of the 12-foot high dam is at elevation 1972.0 ft. The darn is 310 ft. wide, and includes
a 34-foot wide gate and overflow spillway structure at the left (facing downstream) abutment of
the dam.
From a stream flow perspective, it is desirable to perform the dam demolition work during the
mid-winter to early spring months in association with higher planned operational flows. Stream
flow is higher during the summer months due to instream flow requirements for angling and
boating. `The target river flow rate during angling season (April 16' through the first week of June
and Labor Day weekend through the last week of October) is 500 cfs. The target river flow rate
during boating season (first weekend of June through Labor Day weekend) is 800 cfs.
The dam demolition project should commence in early January in order to perform the work
during the planned high operational flow period. Work will be completed by late March to early
April. The removal plan is as follows:
¦ Excavate and remove existing sediment in the forebay area immediately upstream of the
trash racks. Remove or disperse the left training wall in the tailrace to reduce water
velocity and the potential for right bank erosion. These banks will quickly revegetate upon
project completion.
¦ For both units 1 and 2, disconnect the turbine shaft from the generator shaft and lock the
turbine shaft to prevent turbine runner rotation. Open units 1 and 2 head gates and turbine
wicket gates. Open the pad gate on the unit 3 head gate. At full pond, approximately 400
to 500 cfs will flow through the powerhouse in this manner. It may be beneficial to use the
hoc-ram to demolish the entire head gate at unit 3 of the powerhouse to increase flow
through that unit. Maintain erosion protection of the bank adjacent to the forebay and in
the tailrace.
¦ To the extent possible, upstream dam operators (Duke Power) will limit river flow at the
Dillsboro Dam during the 1st phase of dam demolition (excavation of the initial notch in
the dam).
¦ Standard oil booms will be installed downstream of the dam prior to drawdown for
additional stream protection. Draw down the pond to the extent possible via flow through
the powerhouse.
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Duke Po«er FINAL Dillsboro Environmental / Biological Assessment
DAINI REMOVAL PLAN
The crest of the 12-foot high dam is at elevation 1972.0 ft. The dam is 310 ft. wide, and includes
a 34-foot wide gate and overflow spillway structure at the left (facing downstream) abutment of
the dam.
From a stream flow perspective, it is desirable to perform the dam demolition work during the
mid-winter to early spring months in association with higher planned operational flows.
due to instream flow requirements for angling and boating. 'File target river flow rate during
angling season (April I" through the first week of June and Labor Day weekend through the last
week of October) is 500 cfs. The target river flow rate during boating season (first weekend of
June through Labor Day weekend) is 800 cfs.
The dam demolition project should commence in early January in order to perform the work
during the planned high operational flow period. Work will be completed by late March to early
April. The removal plan is as follows:
¦ )excavate and remove existing sediment in the forebay area immediately upstream of the
trash racks. Remove or disperse the left training wall in the tailrace to reduce water
velocity and the potential for right bank erosion. These banks will quickly revegetate upon
project completion.
¦ For both units 1 and 2, disconnect the turbine shaft from the generator shaft and lock the
turbine shaft to prevent turbine runner rotation. Open units I and 2 head gates and turbine
wicket gates. Open the pad gate on the unit 3 head gate. At full pond, approximately 400
to 500 cfs will flow through the powerhouse in this manner. It may be beneficial to use the
hoe-ram to demolish the entire head gate at unit 3 of the powerhouse to increase flow
through that unit. Maintain erosion protection of the bank adjacent to the forebay and in
the tailrace.
¦ To the extent possible, upstream dam operators (Duke Power) will limit river flow at the
Dillsboro Dam during the 1st phase of dam demolition (excavation of the initial notch in
the dam).
¦ Standard oil booms will be installed downstream of the dam prior to drawdown for
additional stream protection. Draw down the pond to the extent possible via flow through
the powerhouse.
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Duke I'mier FINAL Dillsboro Environmental / Biological Assessment
¦ Use the excavator with hoe-ram on the downstream side of the dam to demolish a 6 to 8 ft.
deep by approximately 40 to 60 1t. wide notch in the right abutment of the dam adjacent to
the powerhouse. In conjunction with flow through the powerhouse, this notch is to pass the
full river flow during the staged demolition process.
• Hoe-ram excavation or similar mechanism is most efficiently performed when the
equipment is above the work. As such, the excavator with hoe-ram will work from the
upstream side of the dam. This will be accomplished by creating a narrow working pad in
the reservoir adjacent to the upstream face of the dam. Place temporary 12-inch rock as
needed just upstream of the dam from the left side of the pond out to approximately 150 ft.
from the left abutment. Rock can be placed directly into sediment on the upstream side of
the dam. This will create the working pad for the excavator with hoe-ram to access the
dam from the upstream side. The top of the pad will be placed to slightly below the water
level. Working from the end of this pad, the excavator will reach the left edge of the notch.
Starting at that point, the hoe-ram will excavate the dam in horizontal 3 to 4 ft. lifts. The
excavator will lower the working pad as the work progresses towards the left abutment of
the dam. In this way, the data will be excavated to its base. The working pad will be fully
removed at completion of dam demolition.
• As the dam is removed to its base, the river will spread out from the initial notch and begin
to flow over the mostly demolished dam. As the dam is lowered to 2 to 3 ft. in height, the
excavator can enter the river to excavate the remaining concrete, including the bottom of
the initial notch.
¦ At the completion of the initial notch excavation, and again at completion of excavation of
each 3 to 4 ft. stage, demolition activity will be paused in order to create a deliberate high
flow event (Table 2.1-1). There should be no more than four of these pauses, and the
duration of each pause should not exceed one week.
• No in-stream fish habitat enhancement structures or similar measures (e.g., revetments,
rock veins) will be installed with this project. However, some natural whitewater features
would be installed as part of the removal process if an acceptable design and necessary
funds were obtained.
ENVIRONMENTAL MONITORING PLAN
An environmental monitoring plan (i.e., pre-removal, removal, and post-removal) will be
prepared in consultation with the resource agencies such as the NCWRC, USFWS, NCDWQ,
NCDWR, and ECBI before execution of the full removal. It is anticipated that Duke will meet
with the pertinent agencies and other interested parties via a technical conference to identify any
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Duke Posner FINAL Dillsboro Environmental! Biological Assessment
resource and safety issues prior to the removal. This meeting would ensure the full disclosure
and discussion of relevant removal issues. Several of these agencies (e.g., USFWS, NCDWQ,
NCWRC, and E13CI) and other parties (e.g., local universities) have expressed interest in
participating and/or providing guidance in the monitoring phase of the project
Pre-Removal Monitoring
In association with the preparation of' subsequent license application for the Dillsboro Project, a
considerable amount of information was obtained on the environmental resources within the
Project area. This information will be used in assessing the physical and biological changes
associated with the dam removal and will provide the pre-removal baseline conditions for which
the success of the project will be compared. This information can be found in the Final Dillsboro
License Application submitted to the FERC and Project stakeholders on July 22, 2003. The
license information pertinent to the dam removal project will be provided in a stand-alone pre and
post monitoring plan submitted to the FERC, natural resource agencies, and interested
stakeholders prior to removal of the dam and powerhouse. Information from the subsequent
license application that will be used as baseline data for the removal monitoring includes the
following:
Water Quantity and Quality
¦ Description of current surface and groundwater quantity;
¦ Applicable state water quality standards;
¦ Historic and existing water quality including dissolved oxygen, temperature, point and
non-point sources, sediment quality and quantity, and other standard parameter measures;
¦ Historic and existing minimum and maximum stream flow release data; and
¦ Stream characteristics (e.g., dimensions, depths)
Aquatic Resources
¦ Historic and existing fishery resource data within the Project area and
upstream/downstream vicinity;
¦ Historic and existing macro invertebrate resource data (including mussels) within the
Project area and upstream/downstream vicinity;
¦ IFIM study data;
¦ Rare, threatened, and endangered aquatic species within and adjacent the Project area;
and
¦ A re-survey and verification of the known downstream mussel population.
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Duke Poiser
FINAL Dillshoro Environmental / Biological Assessment
Botanical and Wildlife RCSOUrces
• Existing botanical species and communities within the Project area;
¦ Existing wildlife communities within the Project area; and
¦ Rare, threatened, and endanuercd terrestrial species within and adjacent to the Project
area
Cultural ResoUl-CeS
¦ Known archaeological and historical resources within the Project area
Recreational Resources
• Existing and projected recreational use, needs, and opportunity within, upstream, and
downstream of the Project
Land Use and Aesthetic Resources
¦ Existing land use and aesthetic resources within and adjacent to the Project
Dam Removal Monitoring
During the actual dam removal and demolition period, a specific program associated with the
compliance with existing regulatory standards, as well as safety procedures will be implemented.
This monitoring program will include the following anticipated items (Note: additional details
and sampling regimes to be added upon consultation with the agencies and stakeholders):
• Photographic documentation, as well as GPS locations, of removal conditions at several
monitoring stations throughout the Project including upstream of the Project reservoir,
immediately upstream of the dam, immediately downstream of the dam, downstream of
the dam at the Scott Creek confluence access area, downstream of the dam approximately
one mile and two miles, downstream at Ferguson Fields which is used by the EBCI as a
ceremonial site, and downstream at the mouth of the Tuckasegee River at Fontana Lake.
¦ eater quality sampling including turbidity and settleable solids, dissolved oxygen,
temperature, and pll will be taken at stations upstream and downstream of the darn.
Stream flows will also be documented during this period through use of flow meters. It is
anticipated that two sampling periods a day will be required for the water quality
parameters to address compliance with state standards. Thresholds, based on these
standards or other agency recommendations, will be used to guide continuation of the
removal process. For instance, if the established turbidity threshold is exceeded during
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Duke Poi%cr
FINAL Dillsboro Environmental / Biolobical Assessment
the actual removal (samples taken every half hour), demolition of the dam will cease until
normal ambient levels are attained.
¦ Sediment deposition within the established downstream stations or other areas of
importance will also be monitored and documented during this period.
¦ Bank erosion both immediately upstream and downstream of the dam will be monitored
during this period through visual and photographic techniques. If erosion appears to be
an issue, bank stabilization measures will be installed. A plan to stabilize the banks will
be developed and approved by the agencies before the initiation of the removal process.
¦ Upon initiation of the dam removal and subsequent drawdown of the Project reservoir, a
representative of the EBCI tribal historic preservation office (THPO), along with other
qualified archaeologists, will monitor and document the exposure of any resources of
cultural significance and monitor heavy equipment ground disturbance. If any artifacts
are observed, the demolition of the dam will cease until the artifacts can be properly
documented and catalogued. A plan that describes the methods, process, and discovery
of any archaeological resources will be developed and approved by the EBCI and
NCSI IPO before the initiation of the dam and powerhouse removal.
¦ Appalachian elktoe mussel monitoring will also be conducted during this period and the
post-removal monitoring period. Prior to removal of the dam, the population of this
federally endangered species (and any other mussel species) will be removed with the
necessary agency permits and approvals from the site immediately downstream of the
dam and relocated to an upstream area of similar habitat and known population. 'File
monitoring plan will include documentation of the removal techniques, a description of
the future habitat (i.e., location, substrate, and flows), cataloging and documentation of
individual mussel placement, and individual survivability.
¦ Approximately 500 little brown bats currently inhabit the Dillsboro Powerhouse. Prior to
powerhouse demolition, bat boxes (with designs and placement approved by the NCWRC
and USFWS) will be installed in the vicinity of the powerhouse. The bat boxes will be
monitored for use through the removal and post removal periods.
¦ A report documenting the removal monitoring results will be submitted to the pertinent
agencies upon completion of the activities.
Post Dam Removal Monitoring
During the post dam removal period (timeframe to be determined), a program to determine the
specific physical, chemical and biological changes in the Project area will be conducted. It is
anticipated that the frequency of monitoring will be quarterly the first year after removal and
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Duke Po%%er
FINAL Dillsboro Environmental / Biolotiical Assessment
twice a year through the remaining monitoring program. Duke has stated in the TCST Settlement
Agreement that it will fund the post removal monitoring for the first two years of an anticipated
four or five year program. This monitoring, program will include the following anticipated items
(Note: additional details and sampling regimes to be added upon consultation with the agencies
and stakeholders):
This monitoring plan will include the following elements:
¦ photographic documentation, as well as GPS locations, of post removal conditions at
several stations throughout the Project including upstream of the project reservoir,
immediately upstream of the dam, immediately downstream of the dam, downstream of
the dam at the Scotts Creek confluence access area, downstream of the dam
approximately one mile and two miles, downstream at Ferguson Fields and downstream
at the mouth of the Tuckasegee River at Fontana Lake.
¦ Documentation of physical stream changes through the use of channel cross-sectional
transects installed within the reach of the prior reservoir. Downstream sediment
deposition/redistribution monitoring, substrate type analysis, alterations in channel
morphology, and changes in flow velocity will also be measured along established
stations and transects.
¦ Documentation of bank and sediment stabilization and revegetation. Photographic
stations will be installed to document any erosion and/or strealn headcutting in the
Project area. In areas of stabilized sediment, vegetation colonization will be documented
through the establishment of sampling plots. Monitor any erosion between the river and
adjacent sewer line and road.
¦ Documentation of the upstream and downstream changes in aquatic life such as fisheries
through use of the U.S. EPA's rapid bioassessment protocols (Angermeier and Karr
1986; Barbour et. al., 1999; Karr et. al. 1986). An Index of Biotic Integrity (IBI), which
will be compared to the baseline information already gathered for the subsequent license
application, will be applied to the sampling program. Metrics associated with tile IBI,
including species richness (number of individual types) and composition, trophic
composition (e.g., proportion of predators), abundance (number of individuals) and
condition. The monitoring will be conducted through the use of standard sampling
techniques such as seining and electroshocking.
¦ EPT taxa richness (Ephemeroptera-mayflies, Plecoptera-stoneflies, and trichoptera-
caddisflies), as well as the use of the IBI for macroinvcrtebrates, will also be
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Duke Po»er
FINAL Dillsboro Environmental! Biological Assessment
documented. Aquatic resource stations are expected to be located upstream of the prior
reservoir (control), within the Project area, downstream of the Project area, and upstream
of the Scott Creek and Tuckasegee River confluence.
¦ Documentation of changes in water quality parameters such as dissolved oxygen, pll, and
temperature will be conducted through the use of standard sampling methods and analysis
(e.g., YSI DM multiprobe meter);
¦ Documentation of changes in riparian areas through use of photographic stations and
vegetation plots located throughout the prior reservoir;
¦ Documentation of any exotic plant, aquatic life, or wildlife introductions due to the dam
removal;
¦ Monitoring of the relocated mussel population.
¦ A yearly report documenting the post-removal monitoring results and improvements will
be submitted to the pertinent agencies upon completion of the activities. Quarterly or
semi-annual summary reports will be submitted to the agencies, as required. Action or
contingency plans (e.g., remediation) can then be developed, approved by the pertinent
agencies, and implemented if any problems are found during the monitoring period.
SEDIMENT MANAGEMENT PLAN
The primary focus of the sediment management plan will be to control sediment erosion and
transport below the dam during the demolition process. The plan will promote natural and phased
river sediment transport from the existing sediment deposits upstream of the dam to the river
downstream of the dam. This will be accomplished over the course of the demolition period
during high operational flows and natural high water events (see Table 2.1-1). In association
with construction, some mechanical sediment removal is anticipated upstream of the dam on the
left bank.
Sediment will be managed during the project primarily by:
¦ Allowing sediment transport out of the reservoir following excavation of a notch in the
dam. High flow through the notch will result in incision of an initial channel through the
sediment deposits along the existing thalweg (deepest part of channel in existing
reservoir) and immediately upstream of the notch. The thalweg would likely be deepened
and widened along the existing deeper sections of the reservoir.
¦ Under generally constant flow conditions, the reservoir is expected to rather quickly
come to equilibrium in regards to incision and sediment transport. At that point, a short
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Duke Poi%cr FINAL Dillsboro Environmental / Biological Assessment
duration high flow event will be staged in order to flush sediment deposited just below
the dam to a point further downstream.
• At completion of the high flow event, a best management plan to address localized
erosion and sediment stability issues will be implemented.
• Sediment transport out of the reservoir during high flow/ high water events will
eventually return the river to its pre-dam bank-to-bank Nvidth and depth. It is expected
that natural re-vegetation will occur between flood events
Some erosion and transport of sediment downstream of the dam will be inevitable during the dam
demolition process. Additionally, small pieces of concrete and concrete fines from the dam
demolition will be transported downstream. The staged high operational flow events will
transport and disperse this material well downstream of the dam site. East Fork and West fork
hydro projects can be used to provide 1,500 cfs flushing flow at Dillsboro Dam for three
consecutive days.
The sediment behind the dam is classified as relatively fine-grained silty sand. Based on field
observations, the sediment is relatively free draining. As the pond is lowered, this characteristic
will allow the sediment to drain and stabilize against sloughing rather quickly. It is anticipated
that there will be limited mechanical sediment removal on the left bank (i.e., looking
downstream) immediately upstream of the dam. This sediment will be removed by a backhoe or
similar technique after it has been drained by the drawdown. The quantity of sediment to be
removed will be determined during construction.
The sediment has been tested and has been found to be free of contaminants and hazardous
substances (Attachment F).
COST
The above plan can be implemented at an estimated cost of 5290,000. This cost assumes that the
project can be implemented as described herein.
2.2 Alternatives for the Dillsboro Powerhouse
2.2.1 Alternative A - No Action
Alternative A has been established as a benchmark against which the proposed action of the
Dillsboro Powerhouse may be compared and evaluated from a current baseline. This alternative
is associated with No Action or continued operation of the Project. This alternative would
2.23
Duke Poser FINAL Dillsboro Environmental / Biological Assminent
essentially keep the Project and the associated powerhouse in the present state of operation
(Figure 2.1-1). This project generates a relatively small amount of electricity (912,330 k\Nlh per
year) and will continue to do so under this alternative. The powerhouse, as described below, will
remain intact and in place and will continue generating energy through use of tile Dillsboro
Reservoir. There will be a net loss of generation due to the renegotiation of the Settlement
Agreements.
With this No Action alternative, there would be no new major construction activities and the
current operations and maintenance would continue through the existing and any future license
articles and conditions.
Based on an environmental site assessment of the powerhouse in 2002, no major potential sources
of environmental contamination were identified. There are minor concerns associated with lead-
based paint on the structure and asbestos on the generator/turbine wiring. Although a minor
concern, the level of potential risk was deemed low with no action recommended during
continued operation.
Based on cultural resource surveys conducted by Duke Power, the Project lacks sufficient integrity
to meet National Register of Historic Places (NRHP) criteria. Although the original powerhouse
and dam were built in 1913, both were extensively modified in 1958. The NCSHPO reviewed the
status of the Dillsboro Powerhouse in relation to the National Register of Historic Places and has
noted that the property appears to be eligible in relation to the early history of hydroelectric
generation in western North Carolina. However, they further stated that they are not opposed to
the removal of the structures.
The powerhouse also contains an estimated 500 little brown bats with a significant presence both
inside and outside the powerhouse. Bats have been known to use this facility for years.
2.2.2 Alternative B - Closure
In this alternative, the powerhouse would be left in place with very limited public access. The
entrance of the structure would be locked and a kiosk would be established that describes the
history of the Project and powerhouse and its past importance to the Nantahala Area. With this
alternative, the Project would cease to operate and no longer generate electricity for Duke Power.
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Duke Poiier FINAL Dillsboro Environmental / Biological Assessment
In its present state, the current powerhouse building would not be suitable as a business or other
public building.
Potentially hazardous items (e.g., asbestos) and oil and lubricants are to be removed prior to
closure. NCSHPO suggests that the powerhouse may be important in the context of the history of
electric power development in western NC. Duke will conduct further discussions with the
NCSIIPO to resolve this issue.
The estimated 500 little brown bats would still use the powerhouse as roosting habitat. No other
principal environmental effects are associated with closure of the powerhouse.
2.2.3 Alternative C - Complete Demolition and Disposal
For this alternative, the powerhouse is to be completely demolished down to the original grade.
Hazardous items and oil and lubricants are to be identified and removed prior to commencing the
demolition work. This is the preferred powerhouse option. Equipment is assumed to have no
salvage value to Duke Power. The superstructure is to be demolished and removed from site.
The concrete substructure walls and floors are to be demolished and removed from site. At
completion of demolition, the pits and holes will be filled to a degree that there will be no safety
hazards left on site. The final surface will be vegetated to remain stable during high water events.
2.2.3.1 F_ngineeringAnnls
The powerhouse superstructure and machinery are to be removed prior to the start of dam
removal activities. The estimated duration of removal is 4 to 5 weeks. The removal plan is as
follows:
¦ Perform a survey of the powerhouse for hazardous materials, including asbestos and lead
paint. Oil and lubricants are to be identified.
¦ Remove any over-wintering bats from the powerhouse.
¦ Remove the existing transmitting facility including transformers and wires.
¦ Remove hazardous materials, oil, and lubricants and dispose of in accordance with all
applicable laws and regulations.
¦ Place riprap fill atop the sediment build-up in the forebay to create a work pad for
demolition and loading of debris.
¦ Dismantle or demolish structure above the concrete substructure.
¦ Remove all machinery and electrical components.
2.26
Duke Po%%er
FINAL Dillshoro Environmental / Biological Assessment
¦ Remove or disperse the left training wall in the tailrace to reduce water velocity and the
potential for right bank erosion. These banks will quickly re-vegetate upon project
completion both naturally and with the supplemental herbaceous plantings.
¦ Remove riprap work pad and stockpile for use in the dam removal. Remove sediment in
the forebay as needed to open unit intakes (all three units). Raise or remove headgates to
allow maximum flow through the remaining powerhouse substructure.
The NCSIIPO reviewed the status of the Dillsboro Powerhouse in relation to the National
Register of Historic Places and has noted that the property appears to be eligible in relation to the
early history of hydroelectric generation in western North Carolina. I lowever, they further stated
that they are not opposed to the removal of the structures. Duke will conduct further discussions
with the NCSHPO in association with this issue (Attachment B).
With the demolition of the powerhouse, the estimated 500 little brown bats would lose their
roosting habitat. A mitigation plan will be developed that incorporates measures (i.e., installation
of adjacent bat boxes) to benefit the bat population. No other principal environmental elfiects are
associated with removal of the powerhouse.
COST
The above plan can be implemented at an estimated cost of $200,000. This cost assumes that the
project can be implemented as described herein.
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
3.0 AFFECTED ENVIRONMENT
This section describes the area in which the proposed action (i.e. Dillsboro Dam and Powerhouse
removal) is to occur. This section focuses on describing those resources, which would or could
be affected through the implementation of the proposed action and/or its alternatives. This
includes the discussion of RTE species and their habitats, historic or cultural resources, wetlands,
and other ecologically critical areas. The purpose of this section is to provide information on the
existing conditions and resources within the Dillsboro Dam and Powerhouse project area.
3.1 Existing Information
3.1.1 Local Setting
The Dillsboro Project, FERC # 2602, (Dam, Powerhouse, and Reservoir) is located in
southwestern North Carolina on the Tuckasegee River in Jackson County (see Figure 3.1-1 and
Attachment C for site photographs). The street address is 310 North River Road, Dillsboro,
North Carolina. The approximate coordinates of the property are Latitude (North) 35° - 21' -
58" Longitude (West) 83° - 14' - 55". The facilities are located in and adjacent to the Town of
Dillsboro. The Dillsboro Dam and Powerhouse are located on the Tuckasegee River at
approximately River Mile (RM) 31.7. The Dillsboro Project is within five miles of the Eastern
Band of Cherokee Indians Reservation and less than ten miles from the Great Smoky Mountains
National Park and Nantahala National Forest. There are no federal or tribal lands within or
immediately adjacent to the Project boundaries.
3.1.2 Project Information
PROJECT HISTORY
C. J. Harris constructed the original plant in 1913 to provide electric power for his Blue Ridge
Locust Pin Factory. Harris later formed the Dillsboro and Sylva Electric Company to serve power
to his business and a few commercial customers in the Town of Sylva. Nantahala Power and
Light Company (NP&L) purchased the Dillsboro Project from the Dillsboro and Sylva Electric
Company in 1957. The plant was rehabilitated and placed in operation in 1958. The Federal
Energy Regulatory Commission (FERC) licensed the Project on July 17, 1980. Duke Power, a
division of Duke Energy Corporation (Duke) acquired NP&L in 1988. Duke's Hydro Central
assumed operational control of NP&L's hydro stations in August 2000.
3-1
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Duke Posner FINAL Dillshoro Ensironmental / Biological Assessment
EXISTING PROJECT FACILITIES
The development consists of a reservoir in limited storage mode, dam and powerhouse plus a
small amount of land surrounding the dam, tailrace and reservoir (Attachment C). The electricity
from the generators is regulated by three single-phased transformers located adjacent to the
powerhouse. Duke Power owns approximately 17 acres of land within and adjacent to the Project
and the Dillsboro Reservoir has. approximately 2 miles of shoreline. The Project boundary is
shown superimposed in USGS topography on Figure 3.1-1.
Project Dam
The Dillsboro Dam (also referred to herein as the Project Dam) is a concrete masonry structure
that is about 310 feet in length and 12 feet high (Figure 2.1-1). Major components of the
Dillsboro Dam are listed below, beginning at the left abutment (facing downstream). All
elevations are referenced in U.S. Geological Survey (USGS) datum and are expressed in feet
above mean sea level. Main components of the darn include:
¦ A concrete, non-overflowing section with crest Elevation 1978.2 feet.
¦ An uncontrolled 14 foot-wide spillway section with crest Elevation 1972.0 feet.
• A 20.0-foot wide spillway section with two six foot wide spill gates. The gate sill
Elevation is 1961.0 feet.
• A 197-foot uncontrolled spillway with crest Elevation 1972.0 feet.
¦ A 64.5-foot-wide powerhouse with a brick and concrete superstructure and concrete
substructure.
• An 80-foot long intake section.
• A concrete, non-overflowing section with crest Elevation 1980 feet.
Powerhouse, Generator and Turbine Data
The powerhouse consists of a 64.5-foot wide reinforced concrete substructure and a wood steel
superstructure (Figure 2.1-2). Inside the powerhouse are two generating units. The unit closest to
the open spillway, Unit No. 1, consists of an S. Morgan Smith vertical Francis-type turbine rated
at 276 horsepower (hp) under 12-foot head and 225 revolutions per minute. Connected are a 219
kilovolt-ampere (kVa) Westinghouse generator at 0.80-power factor and a DC exciter. Unit No.
2 has a Leffel Type - Z turbine rated at 44 horsepower (lip) under 12-foot head and 200
revolutions per minute (rpm). Connected are a 62.5 kVa General Electric generator at 0.80-
power factor and a DC exciter. Each unit has an open pit concrete penstock. The rated hydraulic
capacities of the turbines are 190 cfs for Unit 1 and 44 cfs for Unit 2. The maximum and
minimum hydraulic capacities of Unit 1 are 228 cfs and 128 cfs respectively. The maximum and
3-3
Duke Po%%er FINAL Dillsboro Environmental / Biolw,ical Assessment
minimum hydraulic capacities of Unit 2 are 56 cfs and 31 cfs. The average annual generation for
the Dillsboro Project over the period of 1958 to 2002 is 912,330 kWh. Total hydraulic capacity
of the 2 units at the Dillsboro Project is 2S4 cfs.
3.1.3 Drainage Basin Hydrology
The Project is located in a 290 square mile watershed drained by the Tuckasegee River and its
many tributaries. The Tuckasegee River, unlike most rivers in the southeast, flows northward.
The Tuckasegee River originates in the Panthertown Valley area of Jackson County (i.e.,
Nantahala National Forest) in southwestern North Carolina with headwaters such as Panthertown
Creek, Cold Creek, Tanasee Creek, and Slickens Creek. The Duke operated Tanasec Creek, Wolf
Creek, Bear Creek, Cedar Cliff, Glenville, and Tuckasegee reservoirs are located in the upper
portion of the Tuckasegee River (i.e., East Fork and West Fork Projects) and provide significant
influence and flow contribution to the Dillsboro Project waters. The Dillsboro Dam forms a
limited storage impoundment (Dillsboro Reservoir) of approximately 15 acres (full pool) and 0.8
miles in length at a surface elevation of 1,972 feet mean sea level (MSL). The average annual
runoff (river inflow) into the Project Reservoir is 779 cfs with highly variable seasonal flows.
Useful storage at this project is negligible.
The following information is pertinent to the historical stream flow data associated with the
Dillsboro Project:
¦ Drainage Area (sq mi):
• USGS Gage Number:
• USGS Gage Description:
• Gage Drain Area (sq ini):
¦ Period of Record:
¦ Minimal Flow Recorded:
¦ Median Flow:
¦ Maximum Flow Recorded:
¦ Mean Flow:
¦ 7Q10:
290;
03512000 (1933-1981) and 03513000 (1897-2000);
Tuckasegee River at Dillsboro, NC and Tuckasegee
River at Bryson City, NC;
347(03513000);
1933-1981 and Oct. 1897 to Sept. 2000;
160 cfs;
625 cfs;
9,761 cfs;
779 cfs;
183 cfs
34
Duke Po%icr FINAL Dillsboro EnNironmental / Biological Assessment
Table 3.1-1. Historical Stream Flow Data (cfs) Associated %i ith the Dillsboro Project by Month for
the Period 194 through 2000
JAN FEB MAR APR NIAY JUN JUL AUG SEP OCT NOV DEC
Min. 244 217 162 136 130 152 165 190 272 325 318 283
Median 613 490 433 349 374 435 643 794 888 1030 990 777
Max. 6843 4702 6194 4307 8134 5302 6805 8532 9504 9443 7730 9761
Mean 700 580 538 439 497 567 785 948 1090 1246 1115 877
7Q10 350 295 251 194 189 209 265 333 376 487 475 436
NOTE: Flows associated with the Dillsboro Project are influenced by the releases of the West Fork
and East Fork hydroelectric projects.
3.1.4 Water Quality
Duke, U.S. Geological Survey (USGS), and the North Carolina Department of Environment and
Natural Resources-Division of Water Quality (NCDENR-DWQ 2000) have monitored the quality
of water in the Dillsboro Project area and adjacent waterbodies. The USGS and NCDENR-DWQ
gage and monitoring stations are located approximately 18.0 miles downstream of the Dillsboro
Project. A comprehensive assessment of water quality and descriptions of water monitoring
programs for the Tuckasegee River and the associated Little Tennessee River Basin has been
recently published by the NCDENR-DWQ in April 2000 (NCDENR-DWQ 2000). The Project
area and the surrounding basin include some of the highest quality waters in North Carolina.
In general, ambient water quality monitoring data from the Tuckasegee River at Bryson City (i.e.,
18.0 miles downstream of the Dillsboro Dam at Station G8600000) had no indications of any
water quality problems (NCDENR-DWQ 2000). Fecal coliform concentrations at this site have
declined over time. Also, the bioclassification (i.e., use of macro invertebrates as an indicator) of
the river has varied between Good and Excellent with few between-year changes in water quality
(NCDENR-DWQ 2000). The bioclassification site from which this information is derived is
located just downstream of the Dillsboro Dam.
As the water released from the upstream Tuckasegee River impoundments (i.e., West Fork and
East Fork projects) travels downstream, water temperatures in the Tuckasegee River respond
rapidly to changing meteorological conditions. As the water was released from the upstream
projects, the hypolimnetic water warned as it traveled downstream during the spring and
summer, and cooled during the fall and winter. The local meteorology forced the heating and
cooling of the Tuckasegee River as the river temperatures responded to the meteorological
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Duke Po%%er FINAL Dillsboro En%ironmental / Biological Assessment
equilibrium conditions. Thus, Dillsboro Reservoir had no discernable effect on downstream
temperatures.
Based upon dissolved oxygen data collected in 2001 and the NCDENR-DWQ historical data,
oxygen concentrations consistently exceeded the minimum concentrations established by State
water quality standards for the Tuckasegee River. As the water traveled downstream in the
Tuckasegee River, the dissolved oxygen concentrations decreased commensurate with the
warming that occurred. The oxygen concentrations were at or near atmospheric saturation
throughout the entire river, with aquatic plant metabolism more pronounced in the downstream
reaches. As with temperature, no discernable effect on dissolved oxygen was detected from the
Dillsboro Project. The Project is in compliance and in support of all other applicable water
quality standards and designated uses.
3.1.5 Climate
The climate of the Project area is typical of the mountainous region of western North Carolina
with mild summers, cold winters, and a growing season limited to 141 days on average. Average
temperatures for winter and summer are 39° Fahrenheit (F) (4° Celsius) and 72° Fahrenheit (F)
(22° C), respectively (USDA 1997). The total annual precipitation averages 50 inches, including
an average snowfall of 12 inches (USDA 1997).
3.1.6 Topography
The Project area is located in the Appalachian Mountains within the Blue Ridge Physiographic
Province (Schafale and Wcakley 1990), which is characterized by its generally steep,
mountainous topography. Elevations in this area typically range from 1,950 to 2,500 feet MSL
with some higher peaks over 3,200 feet MSL. The topography of the area varies from relatively
flat basins to narrow valleys and from rolling hills to very steep mountains (USDA 1997).
Streams flow through forested coves, narrow and moderately wide floodplains, and small areas of
rock outcrops. The area immediately surrounding the Project area is also generally mountainous
and contains large tracts of forest Nvith few population centers (i.e., Dillsboro, Sylva). Human
developments generally occur in stream and river valleys and are widely scattered due to the lack
of suitable low gradient building sites.
3.1.7 Geology
The landscape around the Project area is very diverse geologically. Tile Appalachian Mountains,
including the Blue Ridge Physiographic Province are suggested to be some of the oldest
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Duke I'mier FINAL Dillsboro Environmental / Biological Assessment
mountains in the world. Ancient tectonic plate and volcanic activity formed these mountains,
which were once as tall and rugged as the Sierra Nevada mountain range, but time and the erosive
forces of nature have reduced them to their current condition. However. the underlying material
has not been changed, and consists of material weathered from higli-grade, metamorphic rocks
such as gneiss and granite (USDA 1997). There are no known active faults in the Project
vicinity.
Gold, silver, gems, and many semi-precious stones and minerals can be found in this area.
Commercial mining operations have utilized these resources in the past, but most areas are
currently used only recreationally.
3.1.8 Soils
The soils of the Project area arc composed primarily of the Evard-Cowee-Saunook-'I'rimont
general mapping unit (USDA 1997). These gently sloping to very steep soils occur on uplands
and in coves in the low mountains of North Carolina (USDA 1997). Slopes range from 2-95
percent creating a hazard for erosion if left unprotected. These well-drained soils are moderately
deep to very deep and can reach depths exceeding 60 inches. These soils formed from material
weathered from high-grade, metamorphic rocks, colluvium, or alluvium and areas of rock outcrop
(USDA 1997).
3.2 Natural Resources
3.2.1 Botanical and Wetland Resources
There are several natural communities with many types of botanical resources located within the
Project area. These natural communities include Montane Alluvial Forest, Sand and Mud Bar,
Rocky Bar and Shore, and Southern Appalachian Bog (Southern Subtype) as described in
Schafale and Weakley (1990). No state or federally listed plant species are currently known to
occur within the Project area. The composition and status of these natural communities are
described below.
Alontane Alluvial Forest (S1/G2?) - This natural community is typically found on stream and
river floodplains at moderate to high elevations (Schafale and Weakley 1990). The canopy in this
natural community is highly variable. Sycamore (Platanus occhlentalis), river birch (Betula
nigra), and black willow (Salix nigra) are typical species along with hemlock (Tsuga
canmlensls), red maple (Ater rubrum), and tulip popular (Liriodendron tulipifera) (Schafale and
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Duke Poi%er FINAL Dillsboro Environmental i Biolo,,ical Assessment
Weakley 1990). The most typical shrubs are great rhododendron (Rhodoclendron maximiurt), tag
alder (Alnus serrtdala) and doghobble (Lei cothoe fonfanesiana). The herb layer may be quite
variable from site to site and potentially occurring species are numerous (Schafale and Weakley
1990).
Sand and Mud Bar (S5/G5) - This natural community is typically found on sites comprised of
sand and mud deposits in and adjacent to streams and rivers, which are too wet, too young, or too
severely flooded to support a forest canopy (Schafale and Weakley 1990). The vegetation
structure is quite variable, ranging from dense to sparse shrubs or herbs, with or without sparse
trees. Typical shrubs include buttonbush (Cephalanlhos occidentalis), swamp rose (Rosa
palustris), elderberry (Sambocos canadensis), and stiff dogwood (Corpus stricta). Some
common herbs include sedges (Carer spp.), rushes (Juncos spp.), common cattail (Tynha
latifolia), and dotted smartwced (Polvoontan punctalunt). A few small trees may also be present
including river birch, black willow, and sycamore (Schafale and Weakley 1990).
Rocky Bar and Shore (S5/G5) - This natural community is typically found on sites comprised
of rock outcrops and gravel bars in or adjacent to rivers and streams, which are too rocky, too
wet, or too severely flooded to support many trees (Schafale and Weakley 1990). The vegetation
structure is quite variable, ranging from dense to sparse shrubs or herbs with or without sparse
bottomland or mesophytic trees (Schafale and Wcakley 1990). Typical shrubs include
buttonbush, tag alder, black willow, silky willow (Salix sericea), silky dogwood (Cornos
amonoun), elderberry, yellowroot (Xanthorhiza simpllclssinia), and giant cane (Arun(linaria
gigantea). Some common herbs include spotted-touch-me-not (Impatiens capensis), sedges
(Carex spp.), smartweeds (Polygonont spp.), rushes (Juncos spp.) (Schafale and Wcakley 1990),
and numerous other species.
Southern Appalachian Bog (Southern Subtype) (S1/G1T1) - This natural community is
typically found on flat or gently sloping areas, generally in valley bottoms that are not subject to
flooding (Schafale and Weakley 1990). Species composition is often a mosaic or zoned pattern
of shrub thickets and herb-dominated areas, much of it underlain by Sphagnum mats (Schafale
and Weakley 1990). Some trees may also be present within the bog itself, but are more often
found on the edges. These species include red maple, white pine, and hemlock. Some common
shrubs may include tag alder, swamp rose, silky willow, great rhododendron and many others.
The herb layer may include sedges (Carex spp.), bullrushes (Schpos spp.), cinnamon fern
3-8
Duke Pm er
FINAL Dillsboro Environmental / Biological Assessment
(O.cl)lt[nda cinnamomea), regal fern (Osmunda regalis), soft rush (Junctes efficsics), chainfcros
(lVoodtirardia spp.), and numerous others all underlain by spliagnutn mosses (Sphagnum spp.)
(Schafale and Weakley 1990).
State Rank:
¦ S I : Critically imperiled in North Carolina because of extreme rarity or otherwise very
vulnerable to extirpation in the state.
• S2: Imperiled in North Carolina because of rarity or otherwise vulnerable to extirpation in the
state.
¦ S3: Rare or uncommon in North Carolina.
• S4: Apparently secure in North Carolina, with many occurrences.
¦ S5: Demonstrably secure in North Carolina and essentially ineradicable under present
conditions.
Global Rank:
¦ G1: Critically imperiled globally because of extreme rarity or otherwise very vulnerable to
extinction throughout its range.
¦ G2: Imperiled globally because of rarity or otherwise vulnerable to extinction throughout its
range.
• G3: Either very rare and local throughout its range, or found locally in a restricted area.
¦ G4: Apparently secure globally, although it may be quite rare in parts of its range (especially
at the periphery).
¦ G5: Demonstrably secure globally, although it may be quite rare in parts of its range
(especially at the periphery).
¦ G?: Unranked, or rank uncertain.
• G_"f_: Status of subspecies or variety; the G-rank refers to the species as a whole, tile T-rank
to the subspecies. Source: NCNIIP 2002 Website.
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey (Duke Power 2003). Wetland development is limited by
the relatively steep topography of the surrounding landscape, lack of floodplain and suitable
substrates.
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
3.2.2 Vegetative Cover
Most of the Project area was previously forest, but a large portion has been cleared and a
considerable amount of private and commercial development has occurred both above and below
the dam. Riparian vegetation has been largely removed, except for a narrow band of trees
immediately along the riverbanks. The remaining wooded areas consist primarily of sycamore,
red maple, tulip popular, alders, black locust, and a few black walnuts. All of the original forest
bordering the Project area has been cut at least once, and most areas are devoid of trees and have
been planted in grasses or are covered in other herbaceous vegetation. Open and fallow fields are
also present in the Project area (Figure 3.2-1).
Seven cover types were identified within the general Project area and each type is described
briefly below.
Grass/Pasture: This type consisted of areas dominated by grasses or other herbaceous species
with little or no trees or shrubs. There were six individual habitat units of this type within the
area ranking it first in area covered. Grass/Pasture habitats are located primarily near developed
areas such as residential dwellings. Many of these areas are actively maintained in a herbaceous
state by human activities or grazing. Typical species of this habitat unit include fescue (Festuca
spp.), broomsedge (Andropogon virginicus) and numerous other herbaceous species.
Hardwood Forest: This type consisted of areas dominated by deciduous trees. There were five
individual habitat units of this type within the area ranking it third in area covered. Hardwood
forest habitats are located primarily away from roads and residential dwellings. Typical species
of this habitat unit include tulip tree, red maple, oaks (Quercus spp.) and hickories (Carya spp.).
Alixed Hardwood/Pine Forest: This type consisted of forested areas dominated by neither
hardwoods nor pines. There were three individual habitat units of this type within the area
ranking it second in area covered. Mixed Hardwood/Pine Forest habitats are located in the
northern and western portions of the area, typically away from roads and residential dwellings.
Typical species of this habitat unit include red maple, oaks, hickories, tulip tree, white pine, pitch
pine (Pinus rigida) and Virginia pine.
3-10
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Land Cover Legend
Grass/Pasture
Hardwood Forest
Mixed Hardwood/Pine Forest
I Pine Forest Figure 3.2-1
Scrub/Shrub
Urban/Built-up Dillsboro Project
Water } - .
' FERC No. 2602
Streams t
Public Roads Covertype Map
' Designated Project Boundary
Y.-nA o soo +.:, ,? r ?:
The covertypes depicted include areas adjacent to the designated project boundary. rp -tom=
Duke Poker FINAL Dillsboro Em ironmental / Biological Assessment
Pine Forest: This type consisted of forested areas dominated by evergreen trees, both naturally
occurring and pine plantations. There were four individual habitat units of this type within the
area ranking it fourth in area covered. Pine Forest habitats are generally located on ridge tops and
along undisturbed drainage ways. Typical species of this habitat unit include white pine, pitch
pine, Virginia pine and hemlock.
Scrub/Shrub: This type consisted of areas dominated by shrubby vegetation. Typically these
areas are former crop or pasture lands (cleared from original forestland) that have grown up in
brush in transition back to forestland. There were three individual habitat units of this type within
the area ranking fifth in area covered. Scrub/Shrub habitats are generally located near roads and
residential dwellings especially current or former farms. Typical species of this habitat unit
include dogwoods (Cornus spp.), alders (ftlnus spp.), multiflora rose (Rosa nmltiflora),
blackberries (Rebus spp.) and elderberry.
Urban/Built-up: This type consisted of areas dominated by residential dwelling and commercial
facilities. There were three individual habitat units of this type within the area ranking it sixth in
area covered. Most of the residential and commercial areas are located north of the Project area.
Water: This type consisted of areas covered by surface water. There was one individual habitat
unit of this type within the area ranking it seventh in area covered. This habitat type consisted of
the Project Reservoir.
3.2.3 Wildlife and Fisheries
The various habitats in the Project vicinity support a diversity of wildlife species. Many
mammals have been reported in the area and include white-tailed deer, gray squirrel, raccoon, and
white-footed mouse. Avian species observed in the general area include Canada goose, wood
duck, red-tailed hawk, indigo bunting, and Carolina chickadee. Several reptile and amphibian
species have also been reported from the area and include eastern box turtle, five-lined skink,
northern water snake, corn snake, northern dusky salamander, gray treefrog, and American toad.
Due to the relatively small size of the Dillsboro Project, there are no significant wildlife
populations or associated habitats found in the Project area.
3-12
Duke Po%%cr
FINAL Dillsboro Environmental / Biological Assessment
Based on existing information, the Little Tennessee River Basin and specifically the Tuckasegee
River exhibits a wide variety of warmwatcr and coolwater fish species. These species include
bass and panfish, minnows, suckers, darters, and trout. During the relicensing studies on the
Tuckasegee River, 42 species of fish were identified. The Project area and the surrounding basin
include some of the highest quality waters in North Carolina. Benthic macroinvertebrate indices
are characterized by Good to Excellent ratings. Several secondary and federal listed species are
also found within the Project and adjacent waters.
During relicensing fishery studies, a total of 11,240 fish representing 42 species were collected
from the six stations sampled for the Dillsboro Project (Figure 3.2-2). Fish abundance and
species diversity varied by location and sample period. Overall, fish abundance and species
diversity increased from upstream to downstream. The average number of fish per sample site
downstream of the Dillsboro Dam (2,952 fish) was 51 percent higher than the average number of
fish per sample site upstream of the dam (1,951 fish). Diversity followed the same trend with an
average of 28 species per station upstream of the dam and an average of 32 species per station
downstream of the dam.
In terms of overall abundance by sample site, the highest numbers of fish were collected from the
downstream Stations T-2 (2,678 fish) and T-1 (2,614), followed by the upstream Station T-4
(2,467), the tailrace Station T-3 (1,977), the most upstream Station T-5 (1,435) and the Dillsboro
Reservoir Station DR (69). With the exception of the tailrace Station T-3, species diversity
decreased from downstream to upstream. Species diversity was highest at the tailrace Station T-3
(38 species), followed by the most downstream Station T-1 (32 species), the Scotts Creek Station
T-2 (28 species) and the two upstream Stations T-4 and T-5 (24 species each). Catches at the
downstream Stations T-1, T-2 and T-3 were generally dominated by minnows, suckers and
darters, while catches at the upstream Stations T-4 and T-5 were dominated by minnows, suckers,
darters and sculpins. The most frequently collected fish from the Dillsboro Reservoir Station DR
were suckers.
The NCWRC has designated public mountain trout waters (i.e., Hatchery-Supported)
immediately downstream of the Dillsboro Dam to the State Route 1534 bridge. They have also
designated Delayed-Harvest trout waters (i.e., artificial lures only and no harvesting between
October 1 and the first Saturday in June) from the Dillsboro Dam upstream to the NC Highway
107 Bridge at Love Field. The DWQ has classified the Project waters as Trout Water (TR). This
3-13
Duke Power FINAL Dillsboro Environmental / Biological assessment
is a supplemental water quality classification intended to protect waters for natural trout
propagation and survival of stocked trout.
Rare, Threatened and Endangered Species
In addition to the list of species common to the Project area, several rare, threatened and
endangered (RTE) species potentially occur in the Project vicinity as well. These species are
listed below.
The wounded darter and olive darter are the only RTE fish species known to occur within the
Project area. These species were documented during relicensing studies immediately downstream
of the Dillsboro Darn. Life history and ecological information associated with these two fish
species are as follows:
Wounded Darter (Etheo.ctonta vulnerahtm)
Protected Status: The U.S. Forest Service lists the wounded darter as a species of concern by the
North Carolina Wildlife Resources Commission and as a sensitive species. The U.S. Fish and
Wildlife Service do not list the wounded darter.
Identification: The wounded darter is a member of the Family Percidae (tile perches) in the
Order Perciformes and of the Etheostoma maculatimi species group of the subgenus Nothonotus.
Body color is gray to dark olive with bright red lateral spotting and the breast is green. Juveniles
(and occasionally adults) have about eight dark saddles and ten dark midlateral blotches that may
extend vertically to be continuous with the dorsal saddles. Sides have dark horizontal lines
between the scale rows. The caudal fin base has a vertical row of four dark spots, two of these
are marginal and two are located near the midline. The soft dorsal, anal, and caudal fins have
narrow dark margins and vague pale submarginal bands. The spinous dorsal fin is dusky with
pigment concentrated to form a dark blotch at the anterior base. The caudal fin typically has a
dark center bordered above and below by a broad red area, but the entire basal portion of the fm
may be red. Paired fins are gray and sometimes there is a dark marginal band on the upper
portion of the pectoral fins. The lateral line is complete, a frenum is present, and the gill
membranes are narrowly joined. The dorsal fm has 12-13 spines and 12-13 soft rays. Tine anal
fin has 2 spines and 7-9 soft rays. The pectoral fin has 13-14 rays and the caudal fin has 17
principal rays.
3-14
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
Distribution: 'file wounded darter is confined to the upper Tennessee River downstream through
Whites Creek and the Little Tennessee River. The wounded darter occurs in the Little Tennessee
River drainage in North Carolina (abundant above Fontana Reservoir) in the Appalachian
Mountain Province. This species was collected in the Tuckasegee River Project area at all
riverine stations but not from the reservoir. It was collected in all seine samples except for
Stations T-4 and T-5.
Habitat Preference: Wounded darter habitat includes moderate to large rivers in areas of gentle
to moderate current. They seem to prefer boulder or coarse cobble substrates; and overhanging
ledges or rocks piled on top of each other are necessary to provide optimum nesting and resting
areas. This darter species will benefit from either the partial removal or full dam removal
alternatives.
Olive Darter (Percina .cgnantata)
Protected Status: The North Carolina Wildlife Resources Commission and the U.S. Fish and
Wildlife Service list the olive darter as a species of concern. The U.S. Forest Service lists it as a
sensitive species.
Identification: The olive darter is a member of the Family Percidae (the perches) in the Order
Perciformes and the subgenus Stivainia. This darter has a long head and relatively pointed snout
and is rather large (5.2 inches TL). The body is olive-brown with dark brown vermiculations on
the upper side and dorsum. There are 13-15 small saddles on the dorsum (these disappear with
age) and on the side there is a midlateral row of 10-12 dark oblong and often confluent blotches
followed by a black round basicaudal spot. The belly is white or yellow. The first dorsal fin has
a dusky green base, an orange submarginal band, and a dusky margin. The second dorsal,
pectoral, and caudal fins are banded with light brown. Other fins are clear. A bold preorbital bar
extends around the snout nearly joining the bar from the other side. Breeding males are overall
much darker than other individuals.
The lateral line is complete, a frenum is present, and the gill membranes are moderately joined.
The dorsal fin has 13-14 spines and 12-13 soft rays. The anal fin has 2 spines and 7-9 soft rays.
The pectoral fin has 12-15 rays and the caudal fin has 17 principal rays.
3-IG
Duke Poser FINAL Dillshoro Environmental / Biological Assessment
Distribution: The olive darter is restricted to upland rivers primarily in the Blue Ridge and
Cumberland Plateau portions of the upper Tennessee and Cumberland River drainages.
Populations occur in Tennessee, Kentucky, Georgia, and North Carolina. The olive darter occurs
in western North Carolina streams in the Appalachian Mountain Province.
This species was collected in the Tuckasegee River Project area only at the downstream riverine
Stations T-1 and T-3 but was not collected from any other riverine station or in the reservoir. It
was not collected in any seine sample.
Habitat Preference: Olive darter habitat includes deep pools and rocky channels in large
streams and rivers with rocky substrates. It is commonly found in strong chutes with cobble and
boulders in high gradient streams, or in the deeper downstream portions of gravel riftles in
streams of moderate gradient. This darter species may benefit from either the partial removal or
full dam removal alternatives.
The Appalachian elktoe and the wavyrayed lampnutssel were the only state-listed or federally
listed species of mussels located within the Project area during relicensing studies (Figure 3.2-3).
These mussels were located both above and below the Project dam. Life history, ecological
information, and other pertinent information associated with these two mussel species is as
follows:
Appalachian F,Iktoe (Alasmidonta raveneliana) (I. Lea, 1834)
Protection Status: Federal Endangered and North Carolina Endangered Species.
In association with the Endangered Species Act of 1973, the USFWS has prepared and enacted a
species recovery plan for the federally endangered Appalachian elktoe mussel (USFWS 1996).
The immediate goal of this plan is to maintain the only known surviving populations and to
protect the remaining habitat from present and future threats (USFWS 1996). According to the
USFWS, the intermediate goal of the plan is to restore and maintain the species throughout a
significant portion of its historic range in the Little Tennessee, French Broad, and Nolichucky
River systems and to downlist the species from endangered to threatened. 'File ultimate goal of
the recovery plan is to recover the species to a point where it can be removed from the hederal
List of endangered and threatened wildlife (USFWS 1996). Reaching this may not be possible
3-17
Duke Power FINAL Dillsboro Ensironmental / Biological .-assessment
however due to the restricted distribution of the mussel and the lack of suitable habitat remaining
in the historic range.
The USFWS has designated critical habitat for this species (Fridell 2001-as published in the
Federal Register-Volume 67, No. 188, September 27, 2002). The areas include: 24 river miles
(38.5 km) of the Little Tennessee River from Franklin Dam downstream to the backwaters of
Fontana Reservoir, Swain and Macon Counties, North Carolina; and, 26 river miles (41.6 km) of
the Tuckasegee River from the N.C. State Route 1002 Bridge in Cullowhee, downstream to the
N.C. Highway 19 Bridge, north of Bryson City, Jackson and Swain counties, North Carolina.
(Note: the second area includes the Dillsboro Project). However, since survey efforts in the
portion of the Tuckasegee River between Dillsboro Dam and Fontana Reservoir are not complete,
a full understanding of the mussel community is not known at this time. There fore, additional
surveys are needed to describe mussel distributions in this river.
Distribution: The known range of the Appalachian elktoe is restricted to tributaries of the
Tennessee River in East Tennessee and western North Carolina. In Tennessee, the species is
known only from a short reach of the Nolichucky River. In North Carolina, it is now known to
occur in short reaches of the Nolichucky, North Toe, South Toe, Cane, Pigeon, and Little rivers
(French Broad River system); and the Little Tennessee, Tuckasegee, and Cheoali rivers (Little
Tennessee River system). Historically, it was also found in Tulula Creek (Little Tennessee River
system), the mainstem of the French Broad River, and the Swannanoa River (French Broad River
system), but has apparently been eliminated from those streams. The Appalachian elktoe has
never been recorded from the Hiwassee River system.
Habitat Preferences: Relatively little is known about the micro-habitat requirements of this
animal. The Appalachian elktoe is known to inhabit relatively shallow, medium-sized rivers and
large creeks with cool, well oxygenated and moderate to fast-flowing water, generally at depths
of less than three feet. It is found in a variety of substrate types including gravel mixed with
cobble and boulders; in cracks in bedrock; and in relatively silt-free, coarse sand. Substrate
stability appears to be critical to the Appalachian elktoe, and it is seldom found in stream reaches
with excessive accumulations of silt or other shifting substrata. With the removal alternative, this
species should benefit (long-term) due to the increases of upstream habitat and the barrier-free
movements of host fish species. Short-term impacts during the removal period can include
increases in sediment-covered substrate.
3-18
Duke Po«er FINAL Dillsboro Emironmental / Biological Assessment
Life History: The Appalachian elktoe is generally identified as a long-term brooder. Ortmann
(1921) reported that the breeding season ended in May, based on four gravid females collected
from the Pigeon River in May 1914. Gravid Appalachian elktoes have been found in the Little
Tennessee River in October through January. Both the banded sculpin (Cottus carolinae) and the
mottled sculpin (C. bairdi) have been identified as fish hosts for this mussel. Based on current
sculpin taxonomy and distributions, the mottled sculpin most likely serves as a host in North
Carolina streams. The life span and many other aspects of this mussel's life history are presently
unknown. Anecdotal observations suggest that it is relatively fast growing and short lived (-10
years).
Wavvraved Laninnutssel (Lanmsilis 1ascinla) Rafinesque, 1820
Protection Status: North Carolina Species of Special Concern
Distribution: The wavyrayed lannpmussel is widely distributed from the Great Lakes, through
the Ohio and Mississippi river basins, as far south as the Tennessee River drainage (Parmalcc and
Bogan 1995). Similar to the Tennessee pigtoe, it is widespread and often locally common in the
Tennessee River drainage and occurs in portions of nearly all of its tributaries, primarily in
headwaters. In North Carolina, it occurs in the Nolichucky and Pigeon rivers (French Broad
River system); the Little Tennessee and Tuckasegee rivers (Little Tennessee River system); and
the Hiwassee River.
Habitat Preferences: This species typically inhabits larger creeks and medium-sized rivers,
usually occurring at depths of three feet or less. Wavyrayed lannpmussels and Tennessee pigtocs
often occur in the same general stream reaches; however, it can tolerate habitats with slower
currents and finer substrata, which are often unfavorable to other species. It reaches its greatest
abundance in moderate currents with a stable sand and gravel bottom.
Life History: In spite of the extensive range and local abundance of the wavyrayed lainpmussel,
its reproductive period is poorly understood. In the Little Tennessee River, the abundance of
gravid females appears to peak in early to mid-sunnmer (June - July), which suggests it is a long-
term brooder; however, some gravid females can be found from early spring through fall. While
the primary host fish is apparently smallmouth bass (jlficropterus dolomei i), it may utilize other
black bass species. This species, like other Lampsilis, produces elaborate lure displays from a
3-19
Duke Poi%er FINAL Dillsboro Environmental / Biological Assessment
hi?.aily modified mantle flap. Females in the Little Tennessee River show exceptional variability
in the types of mimics that they produce.
Relicensin,_, Survev Results
Two mussel species were found immediately downstream from Dillsboro Dam during a 2002
relicensing study. These species arc the wavyrayed lampmussel and the Appalachian clktoe,
which was the most abundant species (Table 3.2-1). A total of 44 individual mussels (41
Appalachian elktoes) were collected and the overall CPUE was 49 mussels per person hour of
search time (Appalachian clktoe CPUE= 4.4). Greatest relative abundance was at and to the left
(descending) side of mid-channel, between 100 and 300 feet (30.5 and 91 meters) downstream
from the dam. One Appalachian elktoe was found within 100 feet of the dam (70 feet [21 meters]
from the dam face, center left quarter of channel). This 100-foot segment immediately
downstream from the dam contained relatively poor mussel habitat, with much of the area
dominated by a deep pool and bedrock substrate. The remaining area surveyed contained
relatively good mussel habitat, consisting primarily of shallow runs with a mix of gravel, cobble,
and sand substrate.
The same two species were found immediately upstream from the Dillsboro impoundment. A
total of 15 mussels (14 Appalachian elktoes) were collected at the upstream site and overall
CPUE was 3.75 mussels per person hour of search time (Appalachian clktoe CPUE= 3.5). A
good distribution of size/age classes (range= 25-76 mm total length) was represented by the
Appalachian clktoe specimens collected from the upstream and downstream sites, indicating
recent reproduction and recruitment at both sites (Fraley 2002).
3-20
Duke Po%%er
FINAL Dillsboro Environmental / Biological Assessment
Table 3.2-1. Mussels Collected Immediately Downstream front Dillsboro Dam, Tuckasegee River
mile 31.7 (phrs= person hours, CPUE= catch per unit effort, Appalachian elk-toe CPUE III
parentheses).
Distance
From Species Channel Quarter
Total
Dam (ft) Common Name Scientific Name Right Center Right Center Left Left
0-100 Appalachian elktoe Alasmidonta raveneliana 0 0 1 0 1
Effort (phrs) 0.5 0.5 0.5 0.5 2
CPUE 0 0 (2) 0 (0.5)
100-200 Appalachian elktoe Alasmidonta raveneliana 4 1 14 6 25
Wa ra ed lam mussel Lam sills lasciola 0 0 3 0 3
Total 4 1 17 6 28
Effort (phrs) 0.75 0.75 0.75 0.75 3
CPUE (5.3) (1.3) 22.7 (18.7) (8) 9.3 (8.3)
200-300 Appalachian elktoe Alasmidonta raveneliana 3 3 8 0 14
Wa a ed lam mussel Lam sills lasciola 1 0 0 0 1
Total 4 3 8 0 15
Effort (phrs) 1 1 1 1 4
CPUE 4(3) (3) (8) 0 3.8 (3.5)
Total Appalachian elktoe Alasmidonta raveneliana 7 4 23 6 40
Wa a •ed lam mussel Lamosilis lasciola 1 0 3 0 4
Total 8 4 26 6 44
Effort (phrs) 2.25 2.25 2.25 2.25 0
The Eastern I lellbender (Crylobranchus alleganiensis) (State and Federal Species of Concern) is
the only RTE amphibian species (i.e., salamander) known to occur within the Project area. This
species was documented during relicensing studies within the Tuckasegee River and within the
Dillsboro Project area (Figure 3.2-3). This large aquatic salamander is found in rivers and large
running streams with an abundance of large boulders, cobble and debris. The species forages on
any small macro invertebrate or invertebrate. The preferred habitat for this species is found in the
Tuckasegee River. No other RTE species are currently known from the Project area.
3.2.3 Land Use
Lands in the vicinity of the Project area are mostly rural with large areas of forest, mountains,
valleys, and some small scale farming operations. Few population centers exist with the majority
of homes being widely scattered. Area land use includes timber harvesting, agriculture, industry,
residential and urban developments, and recreation. The Town of Dillsboro is located in and
adjacent to the Project area. Numerous residential and industrial developments are located along
the Tuckasegee River. There is a commercial business (i.e., inn and bed and breakfast) adjacent
to the Project and powerhouse. There is also a commercial whitewater boating business
downstream of the Project. There are no federal or state lands within or immediately adjacent to
the FERC Project area.
3-21
Duke Power FINAL Dillsboro Environmental / Biological Assessment
3.2.5 Floodplains and Flood Events
Due to the relatively steep topography of the Project area, floodplains are generally narrow and
limited to the Project water bodies and adjacent lands. Floodplains along the Tuckasegee River
are mapped on Federal Emergency Management Agency (FEMA) maps. One hundred-year flood
areas (Zone A) include essentially the entire Project area and some adjacent lands. Flood events
have occurred both prior to and after construction of the Project (Figure 3.2-4).
3.3 Cultural Resources
3.3.1 Archaeological Sites
The North Carolina State Historical Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there. Because of this, no further
archeological assessments were conducted during the relicensing process.
3.3.2 Historical Resources
In 2001 the Project structures were assessed for their eligibility for inclusion on the NRHP
(Thomason and Associates 2001). Each structure was field inspected to detennine its components,
to evaluate its architectural or engineering significance, and to assess its degree of integrity.
Extensive historical research was conducted on these hydroelectric facilities and the overall history
of hydro-power in the state, at the archives of Duke Power in Franklin, North Carolina, and at the
State Archives in Raleigh. Generally, hydroelectric power plants can be significant under NRIIP
criteria A, B, and C. These facilities will most often have the potential to be significant under
NRfIP criterion A in the categories of Commerce, Engineering, Military, Industry, and Social
History.
Under NRHP criterion B, hydroelectric power plants may be significant for their association with a
master builder, architect, engineer, or person of particular influence or vision. Hydroelectric power
plants may also be significant under criterion C for their architectural design or engineering
components.
3-22

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Dillsboro Project
LEGEND + /'/ ; \t l •.
FERC No. 2602
ZONE A JACKSON COUNTY, N.C.
=?1 J)' FLOOD HAZARD BOUNDARY
IMPOUNDMENT IN- E
BOUNDARY S (PANEL NUMBER 370282-0043 C)
0 1,000 1000 3,000 41000
SCALE IN FEET
Duke Power FINAL Dillsboro Environmental / Biolohical Assessment
3.3.3 Previous Cultural Resource Studies
Surveys conducted by USFS archaeologists within the Nantahala National Forest represent the
bulk of published work for the Project vicinity (see Legacy Research Associates, Inc. 2001 for
citations). The North Carolina Department of Transportation (NCDOT) has been responsible for
a number of surveys associated with road improvement projects in the area. Compliance surveys
prompted by various amenity and public works snake up the remainder of the contract surveys.
The NCSIIPO recommended in a letter dated 16 June 2000 that Duke assess the Project structures
for eligibility for inclusion on the NRHP. Thomason and Associates conducted the draft
assessment of the Project structures and concluded that none of the Project structures are eligible
for the NRIIP. Although the original powerhouse and dam were built in 1913, both were
extensively modified in 1958. Due to extent of these alterations, neither the powerhouse nor dam
meets NRHP requirements.
The report was submitted to the NCSHPO, USFS and EBCI on November 8, 2001, and Duke has
received preliminary comments on the recommendation. Preliminary information from the
NCSHPO suggests that the powerhouse may be important in the context of the history of power
development in the Nantahala Area and may be eligible for inclusion on the NRHP.
3.4 Recreation
Currently there are no developed recreational facilities such as boat launches or campsites within
the Project boundaries (Duke 2003). The Town of Dillsboro maintains the two primary access
sites on either side of the river downstream of the dam and Project. One site offers an ADA-
compliant shoreline fishing pier and parking for 15-20 vehicles. The Town of Dillsboro Launch
Port, at the confluence of the Tuckasegee River and Scotts Creek, provides river access via a
gravel boat ramp, has available parking for 10-15 vehicles, and a picnic area. Restroom facilities
are within walking distance of the site. Private paddlers and two of the four commercial outfitters
currently use this access area.
Use of the Project impoundment and immediate tailrace for recreation is limited and occurs only
informally. Within the reservoir, the Dillsboro Project supported approximately 2,300 recreation
days of use between October 2001 and October 2002. Use was distributed fairly evenly
throughout the year (Duke 2003).
3-25
Duke Power
FINAL Dillsboro Environmental / Biological Assessment
'There are no designated Wild and Scenic Rivers, eligible for listing Wild and Scenic Rivers, or
designated wilderness areas or State/national parks within or adjacent to the Dillsboro Project
(NRI 2002). The Tuckasegee River is listed by the National Park Service on the Nationwide
Rivers Inventory (NRI 2002). From River Mile 15 at Bryson City to River Mile 53 at Cedar Cliff
Reservoir, this water body includes values such as diverse scenery and visual appeal, existing and
significant potential for recreational opportunities, interesting geology, significant historical sites,
and high quality fish and wildlife habitat.
3-26
Duke Po%ter FINAL Dillsboro Environmental / Biological Assessment
4.0 ENVIRONMENTAL CONSEQUENCES
4.1 Introduction
This section provides the direct, indirect and cumulative impacts that the various alternatives will
have on the resources characterized in Section 3.0 (Affected Environment). In association with
these impacts, the magnitude of the expected impacts, if any, are described and compared to the
No Action. Where adverse impacts are described, the proposed mitigation measures are also
provided. An EA Significance Checklist, as outlined by the USFWS NEPA guidelines, is
provided in Attachment D.
4.2 Environmental Consequences for Dillsboro Dann
4.2.1 Alternative A - No Action
This section describes the consequences and impacts expected from not implementing any of the
action alternatives and continuing the present Project operations. This section provides the
baseline to which all of the effects of implementing the action alternatives are compared.
This alternative would essentially keep the Project Dam in its present condition. Under
Alternative A, there would be no new major construction or fill discharge (e.g., till associated
with dam maintenance or upgrades) that would occur into waters of the U.S., thus, no new federal
and state permits would be required (does not include the new FERC license and the concurrent
Section 401 Water Quality Certification). The Project is currently in compliance with the
provisions of the National Pollutant Discharge Elimination System (NPDES). Continued
operation of the Project under Alternative A would have no new negative effect on the
environment such as water quality, wetlands, endangered species, aquatic resources and other
sensitive resources (Table 4.2-1).
Table 4.2-1. Summarv of Imnacts by Future Mini Alternatives
Impact
Topics Alternative A
No Action Alternative B
Partial Removal Mternative C
Full Removal
Dam would stay in present Project would cease to Project would cease to operate
condition with no new operate and dam would be and dam would be fully removed.
construction and project partially removed. Section Section 404/401 permits will be
Physical
would continue present 404/401 penuits will be required.
Resources
operations. Section 401 required.
permit will be required.
New FERC license.
4-1
Duke Power
FINAL Dillsboro Environmental / Biolo-ical Assessment
Impact
Topics Alternative A
No Action Alternative B
Partial Removal Alternative C
Full Removal
No new impacts to aquatic Short-term impacts to water Short-term impacts to water
resources, water quality, quality due to alleviated TSS quality due to alleviated TSS and
wildlife, RTE species, and sediment load. Short- sediment load. Short-term
vegetation, land use or term impacts to impacts to macroinvertebrates and
wetlands. Several known macroinvertebrates and fishery resources downstream due
RTE species (darters, fishery resources downstream to sediment release. Benefits
mussels and hellbender) due to sediment release. upstream due to enhanced habitat
immediately downstream of Benefits upstream due to and partial upstream/downstream
dam. Project continues enhanced habitat and partial passage. Additional 9.5 miles of
acting as sediment sink upstream/downstream free-flowing river. RTE fish such
with estimated 100,000 passage. Additional 9.5 miles as darters would be repopulated
cubic yards and no of free-flowing,river. RTE upstream. RTE mussel
significant sediment fish such as darters would be population and critical habitat
contamination concerns. repopulated upstream. RTE would be adversely affected
Biological
Dam continues to act as a mussel population and critical temporarily by sediment and
Resources
barrier to many species of habitat would be adversely change in flows and will be
fish, and other organisms. affected temporarily by relocated to suitable habitat
Reservoir continues to sediment and change in flows upstream. Long-term benefits to
inundate and provide and will be relocated to mussels and benthic macro-
unsuitable habitat for suitable habitat upstream. invertebrates due to an increase in
mussels. Long-term benefits to habitat. Passage for mussel host
mussels and benthic macro- species. Gravel/cobble transport
invertebrates due to an and distribution re-establishment.
increase in habitat. Passage Increase in terrestrial buffer due
for mussel host species. to drawdown.
Gravel/cobble transport and
distribution re-establishment.
Increase in terrestrial buffer
due to drawdown.
No impact to known Possible exposure of Possible exposure of
Cultural archaeological or historic archaeological resources. archaeological resources.
Resources resources. SHPO stated Impacts to potentially eligible Impacts to potentially eligible
that powerhouse might be NRHP powerhouse if NRHP powerhouse if demolished.
4_Z
Duke Power
FINAL Dillsboro Ensironmental / Biological Assessment
Impact Alternative A Mternative B Alternative C
Topics No Action Partial Removal Full Removal
eligible for NHRP due to demolished.
power context.
No developed recreational
facilities in Project Benefits due to increased
Benefits due to increased
Recreational boundary. Project has opportunity with riverine
opportunity with riverine fishing
Resources limited reservoir recreation fishing and whitewater
and whitewater boating.
with barrier to free-floating boating.
boating.
No significant impacts to No significant impacts to
socioeconomic resources. socioeconomic resources.
Perceived socioeconomic loss Perceived socioeconomic loss to
Socio-
No significant impacts to to local business (downstream local business (downstream Bed
Economic
socioeconomic resources. Bed & Breakfast). & Breakfast).
Values
Benefits due to increased Benefits due to increased
whitewater recreation and whitewater recreation and trout
trout fishing opportunities. fishing opportunities.
Aesthetic values and visual
Visual and Aesthetic values would be quality would benefit, although
No significant impacts to
Aesthetic negatively affected by partial the sight and sounds of water
visual and aesthetic values.
Qualities structure remaining in river. flowing over the dam will be
eliminated.
4.2.1.1 Environmental Resources
Natural Communities
There are several natural communities with many types of botanical resources located within the
Project area. These natural communities include Montane Alluvial Forest, Sand and Mud Bar,
Rocky Bar and Shore, and Southern Appalachian Bog (Southern Subtype) as described in
Schafale and Weakley (1990). Riparian vegetation has been largely removed, except for a narrow
band of trees immediately along the riverbanks. The remaining wooded areas consist primarily of
sycamore, red maple, and tulip popular, alders, black locust and a few black walnuts. No state or
federally listed plant species are currently known to occur within the Project area. Because
Alternative A will continue existing Project operations, there is no reason to expect any
4-3
Duke Po«er FINAL Dillsboro En%ironmental / Biological :Assessment
appreciable or permanent changes in the composition, structure or area of the current natural
communities within the Project area.
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative A will not cause any impacts to
wetlands.
Wildlife
The various habitats in the Project vicinity support a diversity of wildlife species as described in
Section 3.0. Because Alternative A will continue existing Project operations, there is no reason to
expect any appreciable or permanent changes in wildlife species or wildlife diversity associated
with the Project.
Water Quality
According to studies conducted for the relicensing of this Project, there are no discernable effects
on temperature or dissolved oxygen and the Project is in compliance and in support of all other
applicable water quality standards and state designated uses. Because Alternative A will continue
existing Project operations, there is no reason to expect any appreciable or permanent changes in
water quality associated with the Project.
Sediment Quantity
Eleven reservoir cross sections were completed in 2002 in association with the relicensing of the
Project and used in the development of a bathymetric map (Figure 4.2-1). The depth to sediment
was derived from the full-pond water depth bathymetry, and volume of sediment was estimated
as follows:
¦ Distance between transects was measured from the bathymetry map from center point of
transect and assumed to be a constant.
¦ Depth at Transect 1 was subtracted from full pond elevation of 1972 ft and assumed to be the
natural bed (1959.4 ft) at the most downstream transect.
¦ Slope of the original bed was estimated by assuming 1972 ft at full pond elevation was the
upstream "natural bed" (outside of reservoir influence) at a distance of 0.8 miles (4224 ft).
Dimensionless slope = (1972-1959.4)/4224 = 0.003 or 0.3 percent.
¦ The "natural bed" was estimated at each cross section using the estimated slope of the natural
bed, and location of each transect along that slope on the long profile. A bathymetry map
4-4
Duke Po«er
FINAL Dillsboro Environmental / Biological Assessment
(Figure 4.2-1) showed the locations of the transects, which were often oblique to flow. It was
assumed that the transect center point defined the location of the transect within the reservoir,
and transect represented a cross section perpendicular to flow. Distance between transects
was measured from the map.
¦ Elevation of the sediment was estimated as 1972 ft (full reservoir water surface) minus depth
to sediment as measured during the 1998 bathymetry survey.
¦ Shape of the channel was assumed to be rectangular which probably results in an
overestimate of the sediment stored within, but is safely conservative for the purposes of this
project.
¦ Depth of sediment at each transect point was calculated by subtracting the sediment elevation
from the estimated natural bed elevation.
¦ Area of each sediment "cell" was calculated using cell width times estimated depth. A "cell"
is the area on each side of the depth measurement that extends halfway to the next depth
measurement (e.g., the midpoint of the cell is the depth measurement and the width is the sum
of half the distance to the next depth measurement on the right and left sides of the current
measurement).
¦ Volume of each sediment cell was calculated by multiplying the length of the cell by the area.
Length of the cell was estimated to be sum of half the distance to the next upstream and
downstream transects.
¦ Uppermost "transect 12" was assumed to be the natural bed about 1000 ft above the last
actual bathymetry transect to get a "zero" point where it was assumed no stored reservoir
sediment exists. This distance was established by calculating the bed elevation at each
transect using the 0.003 slope, and represents the remaining distance within the 0.8 mile
reservoir to bring the bed to 1972 ft.
4-5
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0
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ii
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7
Duke Poirer FINAL Dillsboro Environmental / Biological Assessment
Table 4.2-2 summarizes the estimated values leading to an estimate of sediment volume held
within the reservoir.
Table 4.2-2. Sununary of assumed natural bed elevation, estimated
distance between transects, and calculated volume within Dillsboro
Reservoir.

Transect
Bed Elevation
(ft) Distance to next

upstream transect
ft
Volume
(ft;)
1 1959.4 174 297,182
2 1960.0 209 235,730
3 1961.0 326 312,826
4 1961.7 217 398,522
5 1962.6 304 272,338
6 1963.1 174 176,385
7 1963.7 191 267,380
8 1964.6 323 175,473
9 1965.1 159 212,643
10 1966.9 582 219,171
11 1968.3 496 190,884
12 (assumed) 1971.6 1,069 0
TOTAL 4,224 2,758,535

TOTAL CU.YDS. 102,168
The Dillsboro Project has acted as sediment sink since completion of the dam. Ilowevcr, the
reservoir is now in a steady state and filled to near capacity. Currently, an estimated 100,000
cubic yards of sediment is located upstream of the dam and consists of particles that are generally
less than 10 mm in size. Thickness of the deposits is estimated to be up to 12 feet near the dam
and decreases to zero at the upstream end (i.e., 0.8 miles upstream of the dam).
Sediment Storage in the River Reaches without Reservoir Influence
The reach descriptions are derived from the IFIM (Instream Flow Incremental Methodology
conducted for the Final Dillsboro License Application) study reaches 1 (above the reservoir and
darn) and 2 (below the reservoir) (Figure 4.2-2), and observations from the aerial video of the
entire IFIM study area situated between Bryson City and above the reservoir. Transacts both
upstream and downstream of the reservoir were used in the analysis because the dam and
reservoir are situated somewhat between the two reaches and may have characteristics of both
types of reaches. The transects within the reaches are used to represent habitat types in non-
reservoir influenced sections of the river (e.g., what might exist without a dam).
Observations of the video along most reaches of the Tuckasegee River indicate there is
substantial storage of fine-grained sediment in boulder velocity shadows and in pools. A rough
4-7
Duke Poi%cr FINAL Dillsboro Environmental / Biological Assessment
estimate of the amount of the bed covered by sediment less than 12 mm in particle size was made
by using the substrate coding within transects for the IFIM study that classifies the entire transect
by dominant particles. Each transect in an IFIM study represents a habitat type. The transects
have the substrate coded by size class.
Area of the bed that was covered by small gravel (2-12 nun) and smaller was totaled for the entire
reach (Table 4.2-3 and 4.2-4) by totaling the distance along the transect covered by that size class
and multiplying that linear distance by the area of the reach occupied by that habitat type. An
IFIM study makes the assumption that measurements along a transect that represent a habitat type
are applicable to all other areas of the reach that have a similar classification of habitat type.
Small gravel was used because sieve analysis of the reservoir deposits indicates most but not all
of the sediment passed a 4.75 mm sieve (some were larger) and thus would be sure to analyze all
the potential storage sites for the material stored within, and potentially released from, the
Reservoir. The habitat types and substrate characteristics of Reach 1 (above Dillsboro Dam and
reservoir) and Reach 2 (below Dillsboro Dam and reservoir) are summarized in Table 4.2-3 and
4.2-4.
This calculation indicates that about 16% of the river is filled with particles sized small gravel
and finer (less than 12 min) above the Dillsboro Dam and reservoir, and 21% below. The depth
of these fine-grained sediments was not measured, but was deeper on the margins and in deep
pools (est. 2 ft) and less so in velocity shadows (est. 0.5 ft). Tables 4.2-2 and 4.2-3 show that
pools have a greater portion of the bed covered with fine-grained sediment, with wide riffles, and
boulder runs the second highest. These are considered the "sediment sinks" that will be further
filled with additional inputs of sediment. These "sinks" will likely fill completely before the less
likely positions within steeper, narrower, and faster habitat types become filled.
4-8
,t ??s- )r?• r 1 t r t '••
\ ,.
to Reach ? - 11`1 N1 Stud} ?- ti ?'; *t 1r?? r'fz 1 ?,? .'` ;:
t
_ f' ,r Rc? <r EF i ti`s
i? - 'il?fr^.tyr? 1.15 ; .fir\j t
/??,, r?rrv ? t„?+r.:+r"'1 / !?? ?..YtG t ? `- `-_-• r?.4•.?- +?%?/ r t?r??r
C. it f r r , d 1 r) r, yT? L PI c; „ j?? ( ?? {
•r??..?` ? \Y.?4 Jf!
Dil lsboro Data
,•''^' / C rraC r/-,. ?"; C ? j;.f lr? ?• -...? r ,tii? r'?.rllr ,? ?` 1 i' ?•?-..'."'^a?l ' ? 1 r?
R14- s .".j il??,f 1 471` ?? ^?? 1?'??
t. fi ??-•?r?. ?„ v r /_J St ! ?? IVA32 f ?ti /?Jt (?•?. ?..a; t'.?` s
71
-Reach I - IFIN1 Study'+ y _ -
A't/[.
is ?: ? /`?. •? ,.,F .-- ?.? r ,`?,r` r.:
r •i?, ? .'?? H? t . ,-.% l•??/ rv?r' :•? r t• ""?1 i t ? o ,J ?a .
l.?
t'rtni^-r
Fi`?ui'1Y4.3-21.OCati01l of DIIlSbOro Dam on the Tuckasegee River in relation to IFIN I stud'
reach locations. `
w.
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v
A
ffll??ti . ????i /J?? ? 1 ? ! ?_.ti?` ??+,\ 1?S 4fYtLf ?, J? ^ ?? ? __??`J?/?
r ?,?'d , tact ? _ 1? ?; ~ ?? 1 ` } ''_ -? ,_•_?L??_? ?'', \ } `? J ? ?,/ . ( _
+., RI,(? I ? ! ? •\ ? ` \ ?, ? ...ter _? --' ;1'?---J,' ?% 1 ?
pp., f 1 \ r-
^' / ? f ? • mo't' ?``•^,? ? ?l?l\? ?,? t 1?\? ` ?..-•r'i--'-?'?' "'l? J/?f 1 _?J' ? ?.
10-
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Duke Po%Ner
FINAL Dillsboro Environmental / Biological Assessment
Table 4.2-3. Amount of Reach I (above Dillsboro Dam and reservoir), Tuckasegee River, covered by
particles less than 12 nun as calculated from IFI1I transect data.

Transect

habitat Type
Frequency of
habitat
(fraction of
reach Reach area
occupied by
transect
habitat
ft2 Fraction of
transect
occupied by
particles
<12nim Reach area
occupied by
particles <12nun
(ft2)
1 Wide, shallow riffle 0.011 126,953 0.253 32.161
2 Bldr/bdrk glide 0.063 727,094 0.179 130,121
3 Bldribdrk run 0.070 807,883 0.137 110,581
4 Dec slow pool 0.099 1,142,577 0.604 690,251
5 Cob/ rav riffle 0.110 1,269,530 0.182 231,194
6 Shallow bdrk/bldr run 0.085 981,001 0.134 131,776
7 Dee run/flowing pool 0.058 669,389 0.354 236,900
8 Dee run 0.036 415,483 0.104 43,411
9 Bldr riffle 0.056 646,306 0.108 69,656
10 Bldr/bdrk elide/run 0.139 1,604,224 0.062 100,097

I1 Wide run (bdrk
w/grav
0.029
334,694
0.129
43.214
12 Bedrk shelf run 0.034 392,400 0.043 16,959
Not classified 0.211
SUM ftz 1,836,320

Assumptions Reach length = 14.9 miles 78,672 ft 78,672
Average width (from IFIM transects n=12) = 146.7 ft 147
Area of Reach 2 (ft) 11,541,182

Fraction of reach occupied by sediment < 12 nun. 0.159
Table 4.2-4. Amount of Reach 2 (below Dillsboro Dam and reservoir), Tuckasegee River, covered by
articles less than 12 min as calculated from IFI1I transect data.

Transect

habitat Type Frequency of
habitat
(fraction of
reach) Reach area
occupied by
transect
habitat
ft2 Fraction of
transect
occupied by
particles
<12mm Reach area
occupied by
particles <12nun
(ft2)
I Boulder Run 0.150 492,751 0.166 81,688
2 Chute Tailout 0.079 259.515 0.400 103,751
3 Shallow Fast Pool 0.047 154,395 0.026 4,082
4 Fast Boulder Run 0.087 285,795 0.211 60,356
5 Cobble Boulder Run 0.063 206,955 0.254 52,537
6 Boulder Riffle 0.071 233,235 0.000 0
7 Dec Glide 0.157 515,746 0.100 51,609
8 Still Pool 0.134 440,191 0.614 270,209
9 Dee Fast Pool 0.047 154,395 0.542 83,614
not classified 0.165
SUM ft' 707,845
4-10
Duke Po%rer FINAL Dillsboro Environmental / Biological Assessment
Table 4.24. Amount of Reach 2 (below Dillsboro Dam and reservoir), Tuckasebee River, covered by
narticles less than 12 nun as calculated from IFIJI transect data.

Transect

Habitat Type Frequency of
habitat
(fraction of
reach) Reach area
occupied by
transect
habitat
rt2 Fraction of
transect
occupied by
particles
<12tmn Reach area
occupied by
particles <121un
(1712)

Assum tions: Rcach length = 4.4 miles 23.232 ft 23,232
Average width from IFIM transects n=9 = 141.4ft. 141
Area of Reach 2 ft2) 3,285,005

Fraction of reach occupied by sediment < 12 nun. 0.215
Sediment Quality
The issue of contaminated sediments within the Dillsboro Reservoir was raised during the
scoping of this project and a subsequent sampling assessment was conducted by the USFWS in
the summer of 2003. The final sediment contamination report, that was prepared in partnership
by the USFWS and Duke, is provided in Attachment F of this Final BA (USFWS 2004).
Review of existing data should also address the pathways between contaminant sources and the
sediments of interest, and the areas potentially affected if contaminated sediments were
mobilized. These factors include things like bathymetry of the impoundment, flows, watershed
hydrology and land uses, sediment and soil types, and sediment deposition rates. Many
contaminants preferentially bind to organic matter and fine-grained (silt or clay) sediments.
While a dam is expected to allow fine material to settle and potentially accumulate in shoaling
areas, much of the substrate in the area of the dani is sandy, with little potential for contaminant
accumulation. In sampling of the benthic community conducted by the State in 1999, the
substrate of the Tuckasegee River at Dillsboro (off SR 1378) was 40 to 50 percent sand and
gravel.
Based on the existing information described above and six samples collected from behind the
dam (throughout profile), no significant contaminant concerns were identified within the
Dillsboro Reservoir (see Attachment F of the Final EA for sampling methodology). Eighty-one
percent of all values evaluated were less than the Threshold Effects Concentrations (TECs) (i.e.,
unlikely of toxicological significance). This category included all the data for arsenic, lead and
mercury. No samples exceeded the Probable Effects Concentrations (PECs) (i.e, no samples of
obvious concerns).
4-II
Duke Po%ier FINAL. Dillsboro Environmental / Biological Assessment
To evaluate the <20 percent of samples that fell between the TECs and PECs for cadmium (n= I),
chromium (n=3), copper (n=3), nickel (n=5) and zinc (n=3), a geometric mean of the TECs and
PECs for each element was computed and defined as a "median effects concentration", or
"MEC". From Figure 4.3-3, it is apparent that only two sediment samples exceeded these MECs,
and they were both for nickel. Only two values (both for nickel) exceeded the geometric mean of
the screening values. The highest nickel concentration (41.5 ug/g dry weight) was from a
downstream sediment sample near Dillsboro gage, and the average of the four downstream
samples (27.4 ug/g dry weight) exceeded the average concentration of the six samples collected
within the reservoir (21.8 ug/g dry weight). Accordingly, the nickel concentrations behind the
dam should not be a concern relative to movement downstream where concentrations are slightly
higher. Although nickel was found to be somewhat elevated relative to the screening level, nickel
is a metal with little affinity for aquatic bioaccumulation, biomagnification, and mobilization in
sediments (Connell and Miller 1984). Nickel also has only slight to moderate aquatic toxicity
(USEPA 1986), and the concentrations observed in surface water quality monitoring of the
Tuckasegee River, typically less than a 10 ug/l detection limit (NCDWQ 2000), are lower than
values toxic even to very sensitive aquatic organisms (USEPA 1986, Keller and Zam 1991).
None of the few samples that exceeded the TECs for cadmium, chromium, copper and zinc
exceeded the MECs, and most of the results were still relatively close to the TECs for these
elements. Our review of existing data and an on-site assessment (tier 1) and results of sediment
chemistry (tier 2) indicated no significant sediment contamination. This assessment is limited to
the toxicological properties of the sediments evaluated.
Because none of the samples indicate a toxicological concern, a statistical comparison of
sediments within Dillsboro Reservoir to the sediment samples collected downstream of Dillsboro
Dam was not included or deemed necessary by the USFWS.
4-12
Duke Poser FINAL Dillsboro Environmental 1 Biological Assessment
Figure 4.2-3 (a-h). Elemental contaminant concentrations of sediments collected within the Dillsboro
Reservoir (D1, D2, D3, D4, D5 and 1)6) and domistream of the reservoir (DGI, DG2, BC1 and BC2).
For each clement, results are compared to threshold-effects concentration (TEC) guidelines of
MacDonald et al. (2000) - values below which adverse effects to sensitive aquatic organisms should
not occur-and probable effects concentrations (PECs) - values above which adverse effects to
sediment dwelling organisms may be expected (MacDonald et al. 2000). Some figures also have a
"median effects concentration" (11EC), the geometric mean of the TEC and PEC, for reference.
35.0
30.0
c 25.0
3 20.0
15.0
10.0
i
I 5.0
0.0
a) Arsenic Concentrations
DG1 DG2 BC1 BC2
i
Downstream samples
i
5.0
4.0
3.0
b) Cadmium Concentrations
i
i
i
4-13
D1 D2 D3 D4 D5 D6
Reservoir samples
Duke Poiscr FINAL Dillsboro En%ironmental / Biological Assessment
c) Chromium Concentrations
120
110
100
•? 90
C
80
3 70
60
50
40
30
20
10
i 0
i

4-14
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
d) Copper Concentrations
Duke Poser FINAL Dillsboro Environmental / Biolouical Assessment
e) Lead Concentrations
130
120
110
100
2) 90
3 80
70
-a 60
ai 50
40
30
20
10
0
PEC = 1.0? f) Mercury Concentrations
0.25
i
0.20
s
a?
TEC 0.18
i
3 0.15
0.10
1
0.05
0.00
3

4-IS
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
Duke PoN%er FINAL Dillsboro Ensironmental / Biological Assessment
g) Nickel Concentrations
50(
45 -
40
a' 35
3 30
i
-a 25
20
15
10
I
5
0

F-1

n
i
4-16
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
rnn
h) Zinc Concentrations
i
Duke Power FINAL Dillsboro Environmental / Biological Assessment
The review also indicated that the material upstream of the dam might have low potential to
accumulate contaminants from a physical standpoint, being comprised primarily of sand and
gravel. This is unlike tine sediments and clavs ?vhicli tend to at least serve as weak binding sites
for metals. Finally, it appears that watershed land uses upstream and downstream of the reservoir
are similar and that any mobilized sediments from behind the dam may merely subject
downstream areas to the same sources of contaminants to which they have been historically
exposed.
Thus, if the No Action alternative is pursued, existing sediment conditions of storage and
transport will continue. The storage and transport of sediment within and below the reservoir is
assumed to be in equilibrium with current conditions (i.e., inflow equals outflow) and will likely
not change as a result of no action. In the event the dam is breached by actions other than a
planned dam removal, the effects would be determined by the type and location of the breach and
would mimic partial removal as discussed later in Section 4.0. Furthermore, no significant
sediment contaminant concerns were identified within the Dillsboro Reservoir.
Fisheries and Other Aquatic Resources
Based on existing information, the Little Tennessee River Basin and specifically the Tuckasegee
River exhibits a wide variety of warmwater and coolhvater fish species. These species include
bass and panfish, shiners and dace, suckers, darters, and trout. "The Project area and the
surrounding basin include some of the highest quality waters in North Carolina. Bcnthic
in acroinvertebrate indices immediately downstream of the Project are characterized by Good to
Excellent ratings with a good diversity of species (Duke 2003).
However, the habitat diversity and quality within the impoundment is less suitable for several
species (i.e., darters) than the habitat upstream or downstream of the Project impoundment as
samples during the relicensing studies confirm (Duke 2003). The shallow nature of the Project,
sediment accumulation, and a physical barrier may have contributed to a less suitable fisheries
habitat and corresponding lower species diversity and abundance. The dam has also acted as a
barrier for several redhorse and darter species and this blockage would continue. Because
Alternative A will continue existing Project operations, these factors will continue to affect
species diversity and abundance in the Project.
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Duke Power FINAL Dillsboro En%ironmental / Biological Assessment
Rare, Threatened and Endangered Species
In addition to the list of species common to the Project area, several rare, threatened and
endangered (RTE) species potentially occur in the Project vicinity as well. These species are
listed below.
The wounded darter and olive darter are the only RTE fish species known to occur within the
Project area. These species were documented during relicensing studies. However, the habitat
diversity and quality within the impoundment is less suitable for several species (i.e., darters and
redhorse) than the habitat upstream or downstream of the Project impoundment. The shallow
nature of the Project, sediment accumulation, and a physical barrier may have contributed to a
less suitable darter habitat. Because Alternative A will continue existing Project operations, these
factors will continue to affect these two darters in the Project and restrict their passage upstream
of the Project dam.
The Appalachian elktoe and the wavyraycd lampmussel were the only state or federally listed
species of mussels located within the Project area during relicensing studies. These mussels were
located both above and below the Project dam. The presence and operation of the Dillsboro
facility has had relatively little effect on mussel populations in the Tuckasegee River besides the
blockage of fish host species and the continued loss of mussel habitat within the reservoir.
Reproducing populations of the same species occur both upstream and downstream from the dam
and detention pool, suggesting that the linear distribution of these species is not significantly
affected by the Dillsboro facility.
The Tuckasegee River is now known to support reproducing populations of two mussel species:
Appalachian elktoe and wavyrayed lampmussel. Prior to 1996, the presence of mussels in the
Tuckasegee River was unknown to resource managers. No historical mussel collections are
known from the Tuckasegee River and limited surveys made by TVA in the 1970's found no live
mussels at selected sites between Dillsboro and Bryson City (TVA unpublished data; S.A.
Ahlstedt, US Geological Survey, personal communication, 2001). Observations at that time
suggested that effluent from a paper mill at Sylva produced water and sediment quality conditions
that were unsuitable for mussels. This effluent entered the Tuckasegee River via Scott Creek,
which joins the river approximately 0.25 mile (0.4 km) downstream from Dillsboro Dam.
Changes in operation and improved wastewater treatment at the paper mill that occurred during
the 1970's and 1980's, have apparently improved habitat conditions and helped make the lower
Tuckasegee River suitable for natural mussel recolonization. Mussel populations are a suitable
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
gage to measure the impact of the dam, but the dam may impact the viability of the mussels by
creating a barrier to the exchange of genetic material between the populations.
In 1996, Appalachian elktoes were found near Bryson City and subsequently at other upstream
locales to near Dillsboro. In 1997, both Appalachian elktoes and wavyrayed latnpmussels were
found between the US 441 Bridge and the Dillsboro Dam, and just upstream from the Dillsboro
impoundment (S. Fraley, NCWRC, personal observations; C. McGrath, NCWRC, personal
communication, 1997; North Carolina Department of Environment and Natural Resources 2001).
The results of the Duke surveys add no new species to the known reproducing mussel fauna in the
Tuckasegee River. The species now known to occur downstream from the mouth of Scotts Creek
are the same as those represented by reproducing populations upstream from both the mouth of
Scott Creek and Dillsboro Dam. This suggests that the apparent recolonization of the lower
Tuckasegee River has likely resulted from surviving mussel populations in the reach upstream
from the mouth of Scott Creek.
Land Use
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in land use associated with the Project area.
Floodplains
Due to the relatively steep topography of the Project area, floodplains arc generally narrow and
limited to the Project waterbodies and adjacent lands. Floodplains along the Tuckasegee River
are mapped on Federal Emergency Management Agency (FEMA) maps. One hundred-year flood
areas (Zone A) include essentially the entire Project area and some adjacent lands. Flood events
have occurred both prior to and after construction of the Project. Because Alternative A will
continue existing Project operations, there is no reason to expect any appreciable or permanent
changes in the tloodway or floodplains associated with the Project.
4.2.1.2 Cullnrnl Resrun-ce.v
The North Carolina State Historical Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there. Because Alternative A will continue
existing Project operations, no negative impacts on cultural resources are expected.
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Duke Poi?er FINAL Dillsboro Environmental / Biological Assessment
4.2.1.3 Recreational Resources
There are currently no developed recreation facilities such as boat launches or campsites within
the Project boundary (Duke 2003). The Town of Dillsboro maintains two primary access areas
on either side of the Tuckasegce River downstream of the Project. Use of the Project
impoundment and immediate tailrace for recreation is limited (i.e., fishing and boating) and only
occurs informally. Although the existing Project does provide limited reservoir recreation such as
fishing and boating, it will continue to provide a barrier to free-flowing river types of recreation.
Some local residents find the Dillsboro Dam to be aesthetically pleasing and a tourist attraction.
2.1.4 Social Resources
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in employment or social structure in Jackson County or the
Project area.
4.2.2 Alternative B - Partial Dam Removal
This section describes the various environmental and social conditions that would change in the
event that the Partial Removal Alternative is pursued.
4.2.2.1 Envirottmerttal Re.vottrces
Natural Communities
There are several natural communities with many types of botanical resources located within the
Project area. These natural communities include Montane Alluvial Forest, Sand and Mud Bar,
Rocky Bar and Shore, and Southern Appalachian Bog (Southern Subtype) as described in
Schafale and Weakley (1990). Riparian vegetation has been largely removed, except for a narrow
band of trees immediately along the riverbanks. The remaining wooded areas consist primarily of
sycamore, red maple, and tulip popular, alders, black locust and a few black walnuts. No state or
federally listed plant species are currently known to occur within the Project area. Because
Alternative B will consist of a lowering of the current Project full pond elevations, there may be
short-term impacts to several of the existing natural communities such as the Sand/Mud bar. It is
anticipated that in the long-term (one year plus), these natural communities would reestablish in
certain areas within the restored reach of the river (Shafroth et al., 2002). In areas of stabilized
sediment, at the partially removed darn site, the exposed areas will be seeded or plugged with
native riparian grasses such as Virginia wild rye (Elynurs vitginicuv) and cane (Arundinaria
gigantea). The release of the pulse of sediment will also provide an opportunity for the creation
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Duke Poser FINAL Dillsboro EnNironmental / Biological Assessment
of new areas downstream of the dam site for the recruitment of riparian pioneer plant species such
as willow, alders, and grasses (Shafroth et al. 2002).
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative 13 is not likely to cause any
impacts to wetlands. With the lowering of the current full pond elevation, narrow fringe areas of
emergent and scrub-shrub wetland may become established in certain areas of sediment
deposition along the partially restored river segment. These areas should re-vegetate rapidly due
to the abundance of moisture, presence of seedbank, and the soil fertility.
Wildlife
The various habitats in the Project vicinity support a diversity of wildlife species as described in
Section 3.0. Because Alternative B will entail a lowering of the water level to a lotic condition,
additional but not a significant amount of habitat (e.g., fringe wetlands and additional riparian
areas) for species such as riverine inhabiting amphibians, reptiles, birds, and terrestrial and scmi-
aquatic mammals could be realized with the associated increases in wildlife abundance and
diversity.
Water Quality
According to studies conducted for the relicensing of this Project, there are no discernable effects
on in-stream temperature or dissolved oxygen and the Project is in compliance and in support of
all other applicable water quality standards and state designated uses. In the short-term (i.e., over
the removal period of 10-12 weeks), total suspended solids would increase. However, the
majority of sediments within the current impoundment consist of bedload sands and gravels. But
these suspended solids will be flushed downstream during the scheduled high generation flows.
Bednarek (2001) reported that based on a review of several dam removal projects (with the
majority in higher gradient streams), sediment (sand) flushes out of a turbid river. Recovery time
depends on the length of time sediment has been accumulating, velocity of the river, gradient of
the riverbed, and the removal technique (Bednarek 2001). For example, when the Grangeville
and Lewiston dams on the Clearwater River in Idaho were removed, the pulse of sediment and
silt moved downstream within one week even though the existing reservoir was filled with silt
(Bednarek 2001; Winter 1990). The Clearwater River is a relatively high gradient river.
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Duke Poser FINAL Dillsboro Environmental / Biological Assessment
Sediment Quantity
See Section 4.2.3.2 and Attachment E for a detailed discussion of the sediment quantity, transport
and downstream deposition. The reservoir has been a sediment sink and has accumulated about
102,000 yds3 (2,758,535 ft) of sediment particles that are generally less than 10 mill in size.
Thickness of the deposits is estimated to be up to 12 feet near the darn and decreases to zero at the
upstream end, approximately 0.8 mi upstream. Consolidation and sub-surface particle size is
unknown. Regardless, it is assumed that the reservoir will change from a sediment sink to at least
a partial sediment source. The movement of sediment out of the reservoir depends upon the type
of removal.
Sediment Quality
Based on the existing information from sediment samples collected upstream of the dam
(including studies associated with this EA/BA), no significant contaminant concerns were
identified within the Dillsboro Reservoir (See Attachment F).
The review also indicated that the material upstream of the danl will have low potential to
accumulate contaminants from a physical standpoint, being comprised primarily of sand and
gravel. Finally, it appears that watershed land uses upstream and downstream of the reservoir are
similar and that any mobilized sediments from upstream of the dam may merely subject
downstream areas to the same sources of contaminants to which they have been historically
exposed.
Thus, if Alternative B is pursued, there would be impacts to aquatic life, and water quality due to
the mobilization and transport of sediment downstream of the partially removed darn. However,
these impacts would be ameliorated by the staged removal and concurrent releases of high flows
from upstream reservoirs. Furthermore, no significant sediment contaminant concerns were
identified within the Dillsboro Reservoir.
Fisheries and other Aquatic Resources
Based on existing information, the Little Tennessee River Basin and specifically the Tuckasegee
River exhibits a wide variety of warmwater and coolwater fish species. These species include
bass and panfish, shiners and dace, suckers, darters, and trout. The Project area and the
surrounding basin include some of the highest quality waters in North Carolina. Benthic .
macroinvertebrate indices are characterized by Good to Excellent ratings.
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Duke Po%%er FINAL Dillsboro Environmental / Biological Assessment
Partial removal would also at least enhance the current aquatic resource distribution and species
richness of the upstream areas through limited upstream and downstream passage, especially
during high flows. The partial restoration of lotic conditions to this reach will likely include the
rapid repopulation of native and riverine aquatic fish and benthic macro invertebrates (Gregory et
al. 2002). Kanehl et al. (1997) reported that fish assemblages rapidly changed to a more typical
riverine structure in former impoundments following dam removal (Woolen Mills Dam on the
Milwaukee River, Wisconsin). Stanley et al. (2002), reported that within one year after a dam
removal in Wisconsin (Baraboo River), macro invertebrate assemblages in formerly impounded
reaches did not significantly differ from those in an upstream reference site or in an unimpounded
reach below the former dam site. The partial removal of the dam would allow partial access to
aquatic resources to an additional 9.5 miles of free-flowing river. Partial removal would also
provide long-term benefits to aquatic life including an increase in mussel habitat, passage for
mussel host fish species, and the re-establishment and increased distribution of gravel/cobble
substrates.
In the short-term, the increased transport, scouring and deposition of bedload sediments such as
sands will negatively affect downstream fisheries and macroinvertebrates and small gravels (10
mm in size) move downstream (Bednarek 2001; Stanley et. al. 2002). Depending on the sediment
size and total sediment volume, short-tenn smothering of aquatic life, potential impact to early
season fish eggs, increased turbidity, and clogging of interstitial substrate spaces are possible. It
is anticipated that, based on similar situations such as the Baraboo River example, rapid recovery
will occur in the area below the dam site. Bednarek (2001) reported that based on a review of
several dam removal projects (with the majority in higher gradient streams), sediment flushes out
of a turbid river.
Rare, Threatened and Endangered Species
In addition to the list of species common to the Project area, several rare, threatened and
endangered (RTE) species potentially occur in the Project vicinity as well. These species are
listed below.
The wounded darter and olive darter are the only RTE fish species known to occur within the
Project area. The upstream habitat diversity and quality within the partially restored river stretch
will become more suitable for several riverine species (i.e., darters and redhorse) than the current
habitat of the Project impoundment. The shallow nature of the Project, sediment accumulation,
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
and presence of a physical barrier will be partially rectified resulting in additional suitable habitat
for the darters.
The Appalachian clktoe and the wavyrayed lampmussel were the only state or federally listed
species of mussels located within the Project area during relicensing studies. These mussels were
located both above and below the Project dam, with no suitable habitat within the Project
reservoir. These existing mussel populations and their associated critical habitat found
downstream of the existing dam will now be adversely affected by the partial removal of the darn
due to the following factors:
¦ Bedload inundation of the mussel population with sediments accumulated from the upstream
of the dam. Currently the substrate in the Tuckasegee River below the Dillsboro Dam
consists of cobble/rubble that is relatively free of the finer sediments (i.e., sand/gravel)
known to occur upstream of the Project Dam. The potential re-suspension of these materials
and subsequent bedload transport may have negative effects on the mussel population located
downstream of the dam (Gregory et al., 2002).
¦ Currently the natural stream hydraulics is altered by the presence of the dam. Removing the
dam would change the flow velocity and dynamics within the river and potentially creating a
scouring issue with unsuitable flows. These increased flow velocities could negatively affect
the mussel population located below the current impounded reach (Gregory et al., 2002).
• Scouring may be exacerbated by partial removal of the dam.
With these adverse impacts in mind, the USFWS has proposed mitigation measures that include
the relocation of the entire population of Appalachian elktoes and wavyrayed lampmussel to a
location upstream of the current Project on the Tuckasegee River or other suitable areas. This
relocation will follow standard transplant methodologies and monitoring techniques to ensure that
the population will not be adversely affected. The USFWS will prepare a section 7 permit in
association with the direct take and relocation of the mussel population. A specific monitoring
plan associated with the mussel relocation will be developed and approved by FCRC and the
pertinent natural resource agencies before the execution of this removal project.
The existing hellbender population will benefit through the improvements in suitable habitat
(rocky substrates), increased flows and aeration, and the increase in prey items. The known
population just upstream of the Project should now repopulate the restored riverine stretch
(Figure 3.2-2).
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
Land Use
There will be no significant changes in the existing land use due to this alternative, although the
increased shoreline exposure would benefit the riparian corridor through the potential formation
of new wetlands and terrestrial buffers. Native grasses and cane will be planted in any stabilized
areas in the vicinity of the dam.
Floodplains
Due to the relatively steep topography of the Project area, floodplains are generally narrow and
limited to the waterbody and adjacent lands. With the pursuit of Alternative B, there is no reason
to expect any appreciable or permanent changes in the floodway or floodplains.
4.2.2.3 Cultural Resources
The North Carolina State Historical Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there.
However, the drawdowns associated with this alternative may result in the exposure of
archaeological resources due to the lowering of the floodpool elevation and the subsequent
exposure of littoral areas. Based on comments from the EBCI, a Phase I archaeological
investigation will be conducted in these exposed areas, in addition to the demolition zone, with
supervision by a member of the Tribal Historic Preservation Office. If any sites of importance
are discovered, a protection plan between Duke and the EBCI will be developed.
4.2.2.4 Recreational Resources
The partial removal of the dam will provide almost a mile of additional riverine angling
opportunity for native fish and the delayed harvest managed trout fishery. The limited reservoir
boating will be diminished, however, and replaced by increased opportunity for whitewater
boating and canoeing without the need for a portage around the dam. The partial removal will be
conducted before the Primary Angling Period (first week after Labor Day through the last
weekend of October and April 1 through the first weekend of June) and before the Primary
Boating Period (after the first weekend of June through Labor Day) to avoid potential conflicts
(e.g., sediment issues) with these user groups.
4.2.2.5 Social Reson-ces
Natural aesthetic values of the Project would be diminished with this alternative due to the view
of a partially removed darn structure remaining in the river. Positive man-made aesthetic values,
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Duke Power FINAL Dillsboro Environmental / Biolohical Assessment
such as tite sights and sounds for the water flowing over the dam, will remain. Socioeconomic
values would increase slightly in association with the increased opportunity for whitewater
boating and riverine angling. The partially remaining dam may become a safety issue to the
general public.
4.2.3 Alternative C - Full Darn Removal
This section describes the various environmental and social conditions that would change in the
event that the Full Removal Alternative is pursued.
4.2.3.1 Ennli-onrnental Re.vota-ces
Natural Communities
There are several natural communities with many types of botanical resources located within the
Project area. These natural communities include Montane Alluvial Forest, Sand and Mud Bar,
Rocky Bar and Shore, and Southern Appalachian Bog (Southern Subtype) as described in
Schafale and Weakley (1990). Riparian vegetation has been largely removed, except for a narrow
band of trees imtnediately along the riverbanks. The remaining wooded areas consist primarily of
sycamore, red maple, and tulip popular, alders, black locust and a few black walnuts. No state or
federally listed plant species are currently known to occur within the Project area. Because
Alternative C will consist of a complete change in the current Project full pond elevation, there
may be short-term impacts to several of the existing natural communities such as the Sand/Mud
bar. It is anticipated that in the long-tenn (one year plus) these natural communities would
reestablish in certain areas within the restored reach of the river. Native grasses and cane will be
planted in any exposed and stabilized areas in the vicinity of the dam site. The release of the
pulse of sediment will also provide an opportunity for the creation of new areas downstream of
the dam site for the recruitment of riparian pioneer plant species such as willow, alders, grasses
and other herbs (Shafroth et al. 2002).
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative C is not likely to cause any
impacts to wetlands. With the lowering of the current full pond elevation down to the original
riverbed elevation, narrow fringe areas of emergent and scrub-shrub wetland may become
established in certain areas of sediment deposition along the partially restored river segment.
These exposed areas will revegetate rapidly because of the abundant moisture, nearby soil
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Duke Poser FINAL Dillsboro Environmental / Biological Assessment
seedbanks and seed sources, and soil fertility. Native grasses and cane will be planted in any
exposed stabilized areas in the vicinity of the dam site.
Wildlife
The various habitats in the Project vicinity support a diversity of wildlife species as described in
Section 3.0. Because Alternative C will entail a complete lowering of the water level to the
original lotic condition, additional habitat (e.g., fringe wetlands and additional riparian areas) for
riverine inhabiting species such as amphibians, reptiles, birds, and terrestrial and semi-aquatic
mammals could be realized with the associated increases in wildlife abundance and diversity.
Water Quality
According to studies conducted for the relicensing of this Project, there are no discernable effects
on temperature or dissolved oxygen and the Project is in compliance and in support of all other
applicable water quality standards and state designated uses. Because Alternative C will entail
complete removal of the dam, certain parameters such as dissolved oxygen and temperature will
improve over the long-term due to reduction in impounded waters and subsequent higher water
velocities, increased aeration, and a more diverse bed structure. In the short-term (i.e., over the
removal period of 12-14 weeks), total suspended solids would increase. But these sediments will
be flushed downstream during the high generation flows.
Sediment Quantity, Transport and Deposition
The following information on sediment quantity, transport, and deposition is summarized from
the Final Sediment Study associated with the Dillsboro Project. The report in its entirety can be
found in Attachment E of this document.
1. The Dillsboro Dam has a watershed area of 290 square miles and an estimated mean annual
sediment yield of 84,100 tons (69,200 cubic yards) per year (USGS gauge data). Similar
river stretches such as the Little Tennessee River at Needmore, Nantahala River at Nantahala,
and the Pigeon River at I-iepco have estimated mean annual sediment yields of 110,000 tons
(90,909 cubic yards), 5,900 tons (4,876 cubic yards) and 65,000 tons (53,719 cubic yards),
respectively (USGS 1993).
2. Mean annual flow at Dillsboro Dam is 667 cfs. The 2-year flood is 5,827 cfs and the 10-year
flood equates to 10,868 cfs.
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FINAL Dillsboro Environmental / Biological Assessment
3. Based on bathymetric survey and subsequent analysis, the impoundment at Dillsboro Dam is
estimated to contain 100,000 cubic yards (121,500 tons) of sediment, consisting of fine to
coarse sand. The Dillsboro reservoir acts more as a low gradient alluvial channel than as a
lake.
4. Sediment load at Dillsboro Dam is estimated to be a minimum of 55,419 tons/year and a
maximum of 121,100 tons/year or average daily sediment load of 230 tons/day.
Conservatively, the estimated volume of stored sediment in the impoundment is equal to 1.0
to 2.2 years of mean annual watershed yield. Suspended sediment concentrations increase
rapidly as discharges rise and much of the annual load is conveyed during just a few days
with peak flows.
5. The reservoir has low sediment trap efficiency due to its small size and short one-hour (mean
flow) detention period.
6. With dam removal, no vertical channel inciscment or headcuts are possible in this area due to
the bedrock-controlled system. However, the river's submerged thalweg will widen as this is
the primary fluvial process.
7. Assessment of the channel stability within and through the impoundment indicates threshold
velocities will exceed critical levels and sediment scour is likely.
S. An analysis of the downstream channel indicates that it has a high sediment transport
capacity and sediments released from the dam site will be conveyed rapidly downstream with
little long-term deposition.
9. During a mean daily flow of 667 cfs, the sediment transport rate is 1,951 tons per day. "The
net or available transport is 1,721 tons per day after subtracting the average daily yield of 230
tons per day. Based on the assumed first week load of 25 percent (30,375 tons), it would take
three weeks to transport it downstream. The subsequent release load over three months
would be an assumed 675 tons per day and is much less than the channel's mean net transport
load of 1,721 tons per day and should not accumulate. The two-year frequency flow of 5,527
cfs could convey the reservoir's entire volume of sediment in just two days. It is anticipated
that the sediment's released from the reservoir could form temporary downstream bars during
low flows, but would continue to move downstream and have little long-term impact. With a
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
two-year frequency flow approximately 7 miles and 14 downstream of the dam, it is expected
that all fine grain and sand size sediments will be carried through the reach without
deposition, except temporarily in pools and sheltered bank areas.
10. Critical reservoir banks near homes, utilities, and roads should be monitored and stabilized
with stone riprap or bioengineering techniques as needed.
A high flow event of approximately 667 cfs or greater is required in order to mobilize sediment.
This flow is determined through discharge calculations associated with the East Fork and West
Fork hydroelectric projects. Therefore, it will be necessary for upstream dam operators (Duke
Power Hydro Central) to release these flows at each stage of demolition to accomplish this
flushing of sediment below the dam. Flows associated with the Dillsboro Project are influenced
by releases from the most downstream West Fork hydroelectric development (i.e., Tuckasegee)
and from the most downstream East Fork hydroelectric development (i.e., Cedar Cliff Lake). The
upstream East Fork and West Fork Projects can provide a continuous flow of 1,500 cfs for three
days.
Sediment Quality
Based on the existing information from sediment samples collected upstream of the dam, no
significant contaminant concerns were identified within the Dillsboro Reservoir.
The review also indicated that the material upstream of the dam would have low potential to
accumulate contaminants from a physical standpoint, being comprised primarily of sand and
gravel. Finally, it appears that watershed land uses upstream and downstream of the reservoir are
similar and that any mobilized sediments from upstream of the dam may merely subject
downstream areas to the same sources of contaminants to which they have been historically
exposed.
Thus, if Alternative C is pursued, there would be impacts to aquatic life, and water quality due to
the mobilization and transport of sediment downstream of the fully removed dam. However,
these impacts would be ameliorated by the staged removal and concurrent releases of high flows
from upstream reservoirs. Furthermore, no significant sediment contaminant concerns were
identified within the Dillsboro Reservoir.
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Duke Poker FINAL Dillsboro En%ironmental / Biological Assessment
Fisheries and Other Aquatic Resources
Based on existing information, the Little Tennessee River Basin and specifically tile Tuckascgee
River exhibits a wide variety of warmwater and coolwater fish species. These species include
bass and panfish, shiners and dace, suckers, darters, and trout. The Project area and the
surrounding basin include some of the highest quality waters in North Carolina. Bcnthic
macroinvertebrate indices are characterized by Good to Excellent ratings.
Full removal would enhance the current aquatic resource distribution and species
richness/abundance of the upstream areas through complete upstream and downstream passage.
The restoration of lotic conditions to this reach will likely include the rapid repopulation of native
and riverine aquatic fish and macroinvertebrates (Gregory et al., 2002). Kanehl et al. (1997)
reported that fish assemblages rapidly changed to a more typically riverine structure in former
impoundments following dam removal (Woolen Mills Dam on the Milwaukee River, Wisconsin).
Stanley et al., (2002), reported that within one year after a dam removal in Wisconsin (Baraboo
River), macroinvertebrate assemblages in formerly impounded reaches did not significantly differ
from those in an upstream reference site or in an unimpoundcd reach below the former dam site.
The full removal of the dam would allow access by aquatic resources to an additional 9.5 miles of
free-flowing river.
In the short-term, the increased transport, scouring and deposition of bedload sediments such as
sands will negatively affect downstream fisheries and macro invertebrates and small gravels (10
mm in size) move downstream (Bednarek 2001; Stanley et. al. 2002). Depending on the sediment
size and total sediment volume, short-term smothering of aquatic life, impact to early season fish
eggs, and clogging of interstitial substrate spaces are possible. It is anticipated that, based on
similar situations such as the Baraboo River example, rapid recovery will occur in the area below
the dam site. Bednarek (2001) reported that based on a review of several dam removal projects
(with the majority in higher gradient streams) sediment flushes out of a turbid river. Recovery
time depends on the length of time sediment has been accumulating, velocity of the river,
gradient of the riverbed, and the removal technique (Bednarek 2001). For example, when the
Grangeville and Lewiston dams on the Clearwater River in Idaho were removed, the wave of
sediment and silt moved downstream within one week even though the existing reservoir was
filled with silt (Bednarek 2001; Winter 1990). The Clearwater River is a relatively high gradient
river.
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Duke Poi?er FINAL Dillsboro Environmental / Biological Assessment
Rare, Threatened and Endangered Species
In addition to the list of species common to the Project area, several rare, threatened and
endangered (RTE) species potentially occur in the Project vicinity as well. These species are
listed below.
The wounded darter and olive darter are the only RTE fish species known to occur within the
Project area. The upstream habitat diversity and quality within the restored river stretch will
become more suitable for several riverine species (i.e., darters and redhorse) than the current
habitat upstream of the Project impoundment. The shallow nature of the Project, sediment
accumulation, and presence of a physical barrier will be completely rectified resulting in
additional suitable habitat for the darters.
The Appalachian elktoe and the wavyrayed lampmussel were the only state or federally listed
species of mussels located within the Project area during relicensing studies. These mussels were
located both above and below the Project dam. These existing mussel populations and their
associated critical habitat found downstream of the existing dam will now be temporarily
adversely affected by the complete removal of the dam due to the following factors:
¦ Bedload inundation of the mussel population with sediments accumulated from upstream
of the dam. Currently the substrate in the Tuckasegee River below the Dillsboro dam
consists of cobble/rubble that is relatively free of the finer sediments (i.e., sand/gravel)
known to occur upstream of the Project Dam. The potential re-suspension of these
materials and subsequent bedload transport may have negative effects on the mussel
population located downstream of the dam.
¦ Currently the natural stream hydraulics are altered by the presence of the dam.
Removing the dam would change the flow velocity and dynamics within the river and
potentially create a scouring issue with unsuitable flows. These increased flow velocities
could negatively affect the mussel population located below the current impounded reach.
With these adverse impacts in mind, the USFWS has proposed mitigation measures that include
the relocation of the entire population of Appalachian elktoes and wavyrayed lampmussel to a
location upstream of the current Project on the Tuckasegee River. This relocation will follow
standard transplant methodologies and monitoring techniques to ensure that the population will
not be adversely affected. The USFWS will prepare a Section 7 permit in association with the
direct take and relocation of the mussel population. A specific monitoring plan associated with
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Duke Poi%er FINAL Dillsboro Environmental / Biological Assessment
the mussel relocation will be developed and approved before the execution of this removal
project.
The existing hellbender population will benefit through the improvements in suitable habitat
(rocky substrates), increased flows and aeration, and the increase in prey items. The known
population just upstream of the Project should now repopulate the restored riverine stretch
(Figure 3.2-3).
Land Use
There will be no significant changes in the existing land use due to this alternative although the
increased shoreline exposure would benefit the riparian corridor through the potential formation
of new wetlands and terrestrial buffers. Native riparian grasses and cane will be planted in any
stabilized areas in the vicinity of the dam.
Floodplains
Due to the relatively steep topography of the Project area, floodplains are generally narrow and
limited to the waterbody and adjacent lands. With the pursuit of Alternative C, there is no reason
to expect any appreciable or permanent changes in the floodway or floodplains.
4.2.3.2 Culnrral Resources
The North Carolina State Historic Preservation Office (NCSI-IPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there.
Ilowever, the permanent drawdowns associated with this alternative may result in the exposure of
archaeological resources due to the lowering of the floodpool elevation and the subsequent
exposure of littoral areas. Based on comments from the EBCI, a Phase I archaeological
investigation will be conducted in these exposed areas, in addition to the demolition zone, with
supervision by a member of the Tribal Historic Preservation Office. If any sites of importance
are discovered, a protection plan between Duke and the EBCI will be developed.
4.2.3.3 Recreational Resow-ces
The removal of the dam will provide almost a mile of additional riverine angling opportunity for
native fish and the delayed harvest managed trout fishery. The limited reservoir boating will be
affected, however, and replaced by increased opportunity for whitewater boating and canoeing
without the need for a portage around the dam. The removal will be conducted outside the
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Duke Po%%cr FINAL Dillsboro Environmental / Biological Assessment
Primary Angling Period (first week after Labor Day through the last weekend of October and
April 1 through the first weekend of June) and before the Primary Boating Period (after the first
weekend of June through Labor Day) to avoid potential conflicts (e.g., sediment issues and noise)
with these user groups. This early removal period will also alleviate impacts to spawning fish
and breeding macroinvertebrates.
4.2.3.4 Social Resourres
Natural aesthetic values of the Project will be enhanced with this alternative through the view of
the now free-flowing river stretch with the typical attributes such as rocky substrate, changes in
stream characteristics, and the sounds of flowing and cascading water. However, both visual and
audio values of water flowing over the dam will be lost which is of value to a local Bed &,
Breakfast business and some local residents. Socioeconomic values would increase in association
with the increased opportunity for whitewater boating and riverine angling.
4.3 Environmental Consequences for Dillsboro Powerhouse
4.3.1 Alternative ek -No Action
The No Action Alternative A is the benchmark against which the other proposed alternatives may
be compared and evaluated. This alternative would essentially keep the Project Powerhouse in its
present condition.
Under Alternative A, there would be no new major construction or till discharge (e.g., fill
associated with powerhouse maintenance or upgrades) that would occur into waters of the U.S.,
thus, no new federal and state pennits would be required. The Project will require a 401 Water
Quality Certification. The Project is currently in compliance with the provisions of the National
Pollutant Discharge Elimination System (NPDES). Continued operation of the Project under
Alternative A would have no new negative effect on the environment such as water quality,
wetlands, endangered species, aquatic resources and other sensitive resources.
4.3.1. I Natural Resources
Natural Communities
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in the composition, structure or area of the current natural
communities within the Project area.
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Duke Poiser FINAL Dillsboro Environmental / Biological Assessment
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative A will not cause impacts to
wetlands associated with the Project.
Wildlife
The powerhouse contains an estimated 500 little brown bats with a significant presence both
inside and outside the powerhouse. Bats have been known to use this facility for years. Because
Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes to the powerhouse bat population.
Fisheries
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in aquatic resources or aquatic species diversity associated
with the Project.
Rare, Threatened and Endangered Species
In addition to the list of species common to the Project area, several Rare, Threatened and
Endangered (RTE) species potentially occur in the Project vicinity as well. Because Alternative
A will continue existing Project operations, there is no reason to expect any appreciable or
permanent changes in RTE resources associated with the Project.
Land Use
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in land use associated with the Project area.
Floodplains
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in the floodway or floodplains associated with the Project.
4.3.1.2 Cultural Resotirces
The North Carolina State Historic Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there.
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Duke Poi%cr FINAL Dillsboro Emironmental / Biological Assessment
Based on cultural resource surveys conducted by Duke, the Project lacks sufficient integrity to meet
NRHP criteria. Although the original powerhouse and dam were built in 1913, both were
extensively modified in 1958. Due to the extent of these alterations, neither the powerhouse nor
dam meets NRHP requirements. The NCSIIPO reviewed the status of the Dillsboro Powerhouse
in relation to the National Register of Historic Places and has noted that the property appears to
be eligible in relation to the early history of hydroelectric generation in western North Carolina.
However, they further stated that they are not opposed to the removal of the structures (see
Attachment B for correspondence).
4.3.1.3 Social Resources
Because Alternative A will continue existing Project operations, there is no reason to expect any
appreciable or permanent changes in socioeconomic resources.
4.3.2 Alternative B - Powerhouse Closure
In this alternative, the powerhouse would be left in place with very limited public access due to
safety concerns. The entrance of the structure would be locked and a kiosk would be establi ;lied
that describes the history of the powerhouse and its past importance to the Nantahala area. With
this alternative, the Project would cease to operate and no longer generate electricity for Duke
Power.
4.3.2.1 Natural Resources
Natural Communities
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in the composition, structure or area of
the current natural communities within the Project area.
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative B will not cause impacts to
wetlands associated with the Project.
Wildlife
With the closure alternative, the estimated 500 little brown bats would still use the powerhouse as
roosting habitat. Therefore, Alternative B will not cause impacts to wildlife resources associated
with the Project.
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Duke Power FINAL Dillsboro En%ironmental / Biological Assessment
Fisheries
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in aquatic resources or aquatic species
diversity associated with the Project.
Rare, Threatened and Endangered Species
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in RTE resources associated with the
Project.
Land Use
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in land use associated with the Project
area.
Floodplains
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in the floodway or floodplains associated
with the Project.
4.3.2.2 Cultural Resources
The North Carolina State Historic Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project Reservoir or likely to be found there.
Based on cultural resource surveys conducted by Duke Power, the Project lacks sufficient integrity
to meet NRHP criteria. Although the original powerhouse and dam were built in 1913, both were
extensively modified in 1958. Due to the extent of these alterations, neither the powerhouse nor
dam meets NRHP requirements. The NCSHPO reviewed the status of the Dillsboro Powerhouse
in relation to the National Register of Historic Places and has noted that the property appears to
be eligible in relation to the early history of hydroelectric generation in western North Carolina.
However, they further stated that they are not opposed to the removal of the structures (see
Attachment B for correspondence).
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Duke Po%ier FINAL Dillshoro Ensironmental / Biological Assessment
4.3.2.3 Social Resources
Because Alternative B would result in the powerhouse being closed and left in place, there is no
reason to expect any appreciable or permanent changes in socioeconomic resources. There may
be negative aesthetic values associated with keeping the powerhouse in its current state.
1.3.3 Alternative C - Complete Powerhouse Demolition and Disposal
For this alternative, the powerhouse is to be completely demolished down to the original grade.
This is the preferred powerhouse option.
4.3.3.1 Natural Resources
Natural Communities
Because Alternative C will demolish the powerhouse and restore the site to original elevations
there is no reason to expect any appreciable or permanent changes in the composition, structure or
area of the surrounding natural communities within the Project area. The original footprint will
be revegetated as necessary.
Wetlands
No palustrine wetland areas were identified within the Project during an August 1999 or
September 2002 follow-up field survey. Wetland development is limited by the relatively steep
topography of the surrounding landscape. Therefore, Alternative C will not cause impacts to
wetlands associated with the Project.
Wildlife
With the demolition alternative, the estimated 500 little brown bats would lose the powerhouse as
roosting habitat. To mitigate for this habitat loss, Duke Power will consult with the USFWS and
NCWRC and will erect at least two bat boxes to attract the displaced colony of little brown bats.
These boxes will be built and erected based on specifications and guidelines provided by the
Pennsylvania Game Commission (Butchkowski 1988). Timbers from the powerhouse will be
used to attract the bats to the boxes (i.e., scent impregnated). The boxes will be mounted on
poles with the following placement guidelines:
¦ Erected at least 10 feet off the ground;
¦ Placed in an open area where it gets at least 7 hours of direct sun. The original footprint of
the powerhouse is an ideal location for the bat boxes;
• Within 10-30 yards of vegetation; and
¦ Located in good foraging habitat containing forests, clearings, and wetlands with abundant
insect activity.
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Duke Poi%cr FINAL Dillsboro Environmental / Biological Assessment
Use of the bat boxes will be documented during the post-removal monitoring.
Fisheries
Alternative C will have no appreciable or permanent changes to aquatic resources or aquatic
species diversity associated with the Project.
Rare, Threatened and Endangered Species
Alternative C will have no appreciable or permanent changes to RTE species or habitats
associated with the Project.
Land Use
Alternative C will have no appreciable or permanent changes to land resources associated with
the Project.
Floodplains
Alternative C will have no permanent changes in the floodway or floodplains associated with the
Project.
4.3.3.2 Cultural Resources
The North Carolina State Historic Preservation Office (NCSHPO) stated in a letter dated 16
December 1999 that there are no known archaeological sites located within the floodpool or
shoreline of the Project reservoir or likely to be found there.
Based on cultural resource surveys conducted by Duke Power, the Project lacks sufficient integrity
to meet NRHP criteria. Although the original powerhouse and dam were built in 1913, both were
extensively modified in 1958. The NCSHPO reviewed the status of the Dillsboro Powerhouse in
relation to the National Register of Historic Places and has noted that the property appears to be
eligible in relation to the early history of hydroelectric generation in western North Carolina.
However, they further stated that they are not opposed to the removal of the structures.
4.3.3.3 Social Resources
Alternative C will have no appreciable or permanent changes to the social resources associated
with the Project.
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Duke PwNer FINAL Dillsboro Environmental / Biological Assessment
4.4 Endangered Species Act/Section 7 Consultation
4.4.1 Background Information
This Section requires consultation with the USFWS to ensure that actions associated with the
project arc not likely to jeopardize the continued existence of federally listed threatened and
endangered species, or result in the destruction or adverse modification of designated critical
habitat (Section 7(a)(2) of the Endangered Species Act). Also, it is required that the USFWS
develop and execute programs to conserve threatened and endangered species (Section 7 (a)(1) of
the Endangered Species Act).
Additionally, a Section 7 permit may be required for this project. This permit is required if an
activity designed to further the conservation of a listed species will result in the direct take, result
in the capture or handling, or significantly modify the behavior of a listed species. These
activities can include surveys to determine species distribution, nest monitoring, hatchery
operation, capture and release of listed species, etc. In association with this project, a Section 7
pennit will be required for the removal and relocation of the more than 40 Appalachian elktoes
found immediately downstream of the Dillsboro Dam.
4.4.2 Section 7 Consultation
Section 7 consultation with the USFWS began in 2000 in an effort to identify issues and listed
resources within the Tuckasegee watershed. This effort was directly related and in parallel to the
preparation and submission (July 2003) of the Final FERC License Application for tile Dillsboro
Hydro Project (FERC #2602). "Throughout this process, the USFWS was consulted concerning
the various issues within their jurisdiction, as well as providing the necessary resource guidance.
Based on progress in association with the TCST Settlement Agreement, an initial scoping
meeting was conducted (July 2003) in which the preliminary details and proposed outline of the
EA/BA was described to the Tuckasegee Cooperative Stakeholder Team members including the
USFWS. Details associated with the possible impacts and associated protection measures were
discussed with the USFWS during this and other subsequent meetings.
In addition to this and several other issue update meetings, consultation letters (requests for
information) were sent to the USFWS, as well as the other stakeholders. Responses received
from these stakeholders, as well as the oral comments from the scoping and update meetings were
used to develop this document (Attachment B).
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Duke Po%%er FINAL Dillsboro EnsironmentaI / Biological Assessment
Based on this information, the USFWS and the other interested natural resource agencies decided
that the most feasible mitigative protection measure is to relocate the Appalachian elktoe
population immediately downstream of Dillsboro Dam due to the destruction and adverse
modification of the mussel critical habitat that would occur if the dam is partially or fully
removed. It is assumed that post-dam removal options would allow for natural recolonization
after the substrate has stabilized.
The partial or full removal of the Dillsboro Dam will constitute a direct take of the Appalachian
elktoe and thus a takings permit will be required for the Project. This pennit will be initiated,
prepared, and executed by the USFWS-Asheville (NC) Field Office and will be associated with
the handling, removal, and relocation of the mussel population to a currently unknown but
suitable location upstream on the Tuckasegee River. This takings permit will include additional
detailed surveys to detennine the species distribution below the darn, handling and relocation
methods, and the subsequent monitoring of the transplanted population. Specific details of the
pennit, along with proposed habitat characteristics will be provided in the future through
discussions between the USFWS and Duke Power.
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Duke Power FINAL Dillsboro Environmental / Biological Assessment
5.0 LITERATURE CITED
American Rivers. 2002. "File ecology of dam removal: A summary of benefits and impacts.
Washington, D.C. 15 pp.
American Society of Civil Engineers (ASCE). 1997. Guidelines for retirement of dams and
hydroelectric facilities. ASCE. New York, New York. 222 pp.
Angenneier, P.L., and Karr, J.R. 1986. Applying an index of biotic integrity based on stream
fish communities: considerations in sampling and interpretation. North Amer. J. of
Fisheries Man. 6:418-429.
Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling. 1999. Rapid bioassessment
protocols for use in streams and wadeable rivers: periphyton, benthic
macro invertebrates, and fish. 2d ed. EPA/841-B-99-002. Washington, D.C: U.S. EPA.
Bednarek , A.T. 2001. Undamming Rivers: A review of the ecological impacts of dam removal.
Environ. Man. Vol. 27, (6): 803-814. pp.
Butchkowski, C. 1996. Bat Box Plans. PA. Game Commission, Bureau of Wildlife
Management, Wildlife Diversity Section.
Connel., D.W. and G.J. Miller. 1984. Chemistry and Ecotoxicology of Pollution. John Wiley
and Sons. New York, N.Y.
Doyle, M.W., E.H. Stanley, J.M. Harbor. 2003. Channel adjustments following two dam
removals in Wisconsin. Water Resources Research, Vol. 39 (1): 10011.
Duke Power. 2003. Dillsboro Hydroelectric Project (FERC No. 2602) Final License Application
(Volume I).
Federal Energy Regulatory Commission (FERC). 2001. Hydropower Licensing and Endangered
Species Act: A Guide for Applicants, Contractors, and Staff. FERC. Office of Energy
Projects. Washington D.C. 60 pp. plus appendices.
Fraley, S.J. 2002. Mussel surveys associated with Duke Power Nantaliala area projects in the
Little Tennessee and Hiwassee River Systems. Report to Duke Power Company. 37 pp.
5-l
Duke Poker FINAL Dillsboro Environmental / Biological Assessment
Fridell, J.A. 2001. Endangered and threatened wildlife and plants: proposed designation of
critical habitat for the Appalachian elktoe. 50 CFR Part 17, RIN 1018-AH33. Federal.
Register 66(27): 9540-9555.
Gregory, S., 11. Li, and J. Li. 2002. The conceptual basis for ecological responses to dam
removal. Bioscience. Vol. 52, (S): Aug.
Hart, D.D., T.E., Johnson, K.L. Bushaw-Newton, R.J., Horwitz, A.T. Bednarek, D.F. Charles,
D.A., Kreeger, and D.J., Velinsky. 2002. Dam removal challenges and opportunities for
ecological research and river restoration. BioScience 52(8):669-651.
Heinz Center for Science, Economics, and the Environment. 2003. Dam removal research: status
and prospects. William L. Graf (eds.). The Heinz Center, Washington, D.C. 151 pp.
Heinz Center for Science, Economics, and the Environment. 2002. Dam removal: scicnce and
decision making. The Heinz Center, Washington, D.C. 151 pp.
Infol-larvest, Inc. 2003. Criterium Decision Plus Users Guide. Seattle, WA. 447 pp.
Kanehl, P.D., J. Lyons, and J.E. Nelson. 1997. Changes in the habitat and fish community of the
Milwaukee River, Wisconsin, following removal of Woolen Mills Dam. North Amer. J.
of Fisheries Man. 17:387-400.
Karr, J.R., Fausch, K.D., Angermeier, P.L., Yant, P.R., and I.J. Schlosser. 1986. Assessing
biological integrity in running waters: a method and its rationale. Illinois Natural History
Survey Special Publication Number 5. 28 pp.
Keeler, A. E., and S.G., Zam. 1999. The acute toxicity of selected metals in freshwater mussel,
Anoclonla intbecillis. Environ. Toxicol. Chem. 10:539-546.
Matthaei, C.D., K.A. Peacock, and C.R. Townsend. 1999. Scour and fill patterns in a New
Zealand stream and potential implications for invertebrate refugia. Freshwater Biology
42, pp. 41-57.
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Duke Poi%er FINAL Dillsboro Ensironmental / niolobical Assessment
Milone and MacBroom. 2004. Sediment study: relating to the removal of the Dillsboro Dam,
Tuckase ,ee River, Jackson County, NC. Prepared for Duke Power arid Devine Tarbell ?C
Associates. March.
National Park Service. 1952. The Nationwide Rivers Inventory. DOI. Washington, D.C.,
January. 432 pp.
Nationwide Rivers Inventory. 2002. North Carolina Segments. NPS, DOI. Online document:
htti)://%vww.ncrc.nt?s.<L,ov/programs/rtcal, nri/states"ric.litml
North Carolina Department of Environment and Natural Resources - Division of Water Quality,
2000. Basinwide Assessment Report-Little Tennessee River. Raleigh, North Carolina.
April 2000. 83 pp.
Schafale, M.P. and A.S Weakley. 1990. Classification of the Natural Communities of North
Carolina. Third approximation. North Carolina Natural Heritage Program. Raleigh, NC.
325 pp.
Shafroth, B., J.M. Friedman, G.T. Auble, M.L. Scott, and J.11. Braatne. 2002. Potential
responses of riparian vegetation to darn removal. Bioscience Vol. 52, (8): Aug.
Stanley, E.H., M.A. Luebke, M.W. Doyle, and D. W. Marshall. 2002. Short-tern changes in
channel form and macroinvertebrate communities following low-head dam removal. J.N.
Am. Benthol. Soc. 21(1):172-187.
Tennessee Valley Authority (TVA). 2002. Nolichuky Reservoir Flood Remediation Project:
Draft EIS. Norris TN. 215 pp. plus appendices.
The Aspen Institute. 2002. Dam removal: A new option for a new century. Washington, D.C.,
68 pp.
USEPA. 1986. Ambient water quality criteria for nickel. EPA 440/5-86-004. Office of Water
Regulations and Standards, Criteria and Standards Division. Washington, D.C.
USFWS. 2004. Sediment contaminants at Dillsboro Reservoir: report on site assessment and
sediment analyses. USFWS Asheville and Raleigh offices, NC. Final report. January.
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FINAL Dillsboro Environmental / Biological :assessment
USF%k'S. 1996. Recovery Plan for the Appalachian Elktoe (Alasintidonta raveliana). USFWS,
Southeast Region. Atlanta, Georgia. 44 pp.
USFWS. Undated. Revised Implementing Procedures for NEPA.
USGS. 2002. Assessment of stream quality using biological indices at selected sites in the Red
Clay and White Clay Creek basins, Chester County, Pennsylvania, 1981-1987. USGS
Fact Sheet FS-118-02. December, 2002.
USGS. 1993. Sediment Characteristics of North Carolina Streams, 1970-1979. USGS Water
Supply Paper 2364. 84 pp.
Vanoni, Vita (ed.). 1975. Sedimentation Engineering. Prepared by the ASCE Task Committee
for the preparation of the Manual on Sedimentation of the Sedimentation Committee of
the Hydraulics Division. New York, NY 745 pp.
Whitelaw, E. and E. Macmullan. 2002. A framework for estimating the costs and benefits of
dam removal. Bioscicnce Vo. 52, No. S. Aug.
Winter, B.D. 1990. A brief review of dam removal efforts in Washington, Oregon, Idaho, and
California. US Department of Commerce. NOAA Tech. Memo. NMFS F/NWR-28, 13
PP.
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FINAL Dillsboro Environmental / Biological Assessment
6.0 COMPLIANCE, CONSULTATION AND COORDINATION WITH
OTHERS
6.1 List of Preparers
The persons responsible for preparation of this Environmental Assessment/Biological Assessment
include representatives from Duke Power, Devine Tarbell & Associates, Inc. (DTA), Milone and
MacBroom, and the USFWS and are as follows:
NAME EDUCATION and EXPERIENCE RESPONSIBILITIES
Mr. Scott Fletcher, CWB, B.S. Wildlife Biology;
PWS MEM Ecology
Biology; 18 years as wildlife
and wetland scientist; Certified
Wildlife Biologist, Professional
Wetland Scientist
Ms. Kathi Peacock B.S. Soil Science;
M.S. Geomorphology;
18 years experience in
watershed planning and
geomorphology
Mr. William Maynard, RE, B.S. Civil Engineering;
Masters of Engineering;
23 years experience in hydropower
engineering; P.E.
IN NC, VA, SC
Mr. Jay Wylie B.S. Wildlife Biology;
3 years experience
Mr. Gregory Cole, EIT B.S Civil Engineering;
B.S Forestry/Wildlife Science
Project Scientist;
Data collection,
report preparation,
B/C analysis; DTA
Project Scientist;
report preparation,
sediment quantity
and transport analysis;
DTA
Project Engineer;
engineering report
preparation and
cost calculations; DTA
Assistant Scientist;
Data collection, report
preparation; DTA
Assistant Engineer
engineering report
preparation.
Analysis; DTA
6-1
Duke Poner
Mr. Stephen Dietzko, P.E, B.S. Civil Engineering; Project Engineer;
15 years experience in civil engineering sediment report
P.E. in SC, NC, NY, CT, IA analysis and preparation
Milone and MacBroom
Mr. James MacBroom, P.E, B.S. Civil Engineering; Project Engineer;
Masters of Science, Civil Engineering; sediment report
31 years experience in hydraulic, analysis and preparation
fluvial morphology, and modeling; P.E. Milone and MacBroom
in CT, NY, IL, MA, PA, NH
Mr. Mark Cantrell B.S. Wildlife and Fisheries Science Project Scientist
M.S. Wildlife and Fisheries Science sediment contamination
18 years experience in wildlife biology, report; USFWS
fisheries, and endangered species
conservation
Mr. Tom Augspurger B.A. Environ. Studies and Biology Project Scientist
M.S. Ecol. And Environ. Toxicology sediment contamination
15 years experience in environ. report; USFWS
contamination program
FINAL Dillsboro Environmental / 6iolobical Assessment
6.2 List of Contacts
The following is a list of state and federal agencies contacted during the planning process.
Attachment B provides the correspondence with these agencies.
NAME
State Resource Agencies
PERSON CON"rACTED
PURPOSE
NCWRC
NCWRC
NCWRC
NC Dept. of Environment
Mr. Chris Goudreau
Mr. Steve Fraley
Mr. David Yow
Mr. John Finnegan
Scoping, NCWRC hydropower
coordinator
Scoping, mussel information
Scoping, fisheries
Endangered species
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Duke I'mNer
FINAL Dillsboro Environmental / Biological Assessment
and Natural Resources,
Natural I leritage Program
NC Dept. of Environment
and Natural Resources,
Division of Water Quality
NC Dept. of Environment
and Natural Resources,
Division of Water Resources
NC Dept. of Cultural
Resources Division of
Archives and History
Federal Resource Af_yencies
United States Dept.
of Interior, USFWS
Information Specialist
Mr. Kevin Barnett
Mr. Steve Reed
Scoping, Section 401 Water
Quality Certification
Scoping, water
resource issues
Ms. Renee Gledhill-Earley, Archaeological and Cultural
Environmental Review Resources, NRHP
Coordinator
Mr. Mark Cantrell,
Mr. Torn Augspurger
United States Dept. Mr. Donley Hill
of Agriculture, USFS
United States Dept. --------------------
of Interior, National
Park Service
United States Dept. Mr. Dave Baker-
of Defense, Army Corps
of Engineers-Asheville Field Office
Tennessee Valley Authority Jon M. Loney
Scoping, USFWS NEPA
requirements and mitigation,
endangered species, sediment
contamination analysis and
report preparation
Scoping, sediment issues
National Wild and Scenic
Rivers
Scoping, Section 404 Permitting
Downstream Impacts and
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Duke Poi%er FINAL Dillsboro Environmental / Itiolooical Assessment
Permitting Issues
Tribal Resource A(encies
Eastern Band of Cherokee Mr. Mike Bolt and Tribal issues, cultural
Indians Ms. Lora Taylor resources
Local Governmental Agencies
Town of Dillsboro Ms. Jean Hartbarger, Mayor Scoping
Town of Sylva Ms. Brenda Oliver Scoping
Jackson County Mr. Ken Westmoreland, Scoping
County Manager
Mr. Tom Massie Scoping
Soil and Water Conservation
District
6.3 Pertinent Regulations, Laws, and Executive Orders
The following environmental regulations have been investigated and are being complied with in
association with the Dillsboro Dam removal project.
¦ Army Corps of Engineers - Section 404 permit application to be submitted;
¦ TVA- Navigable waters permit under Section 26A of the TVA Act- removal of the dam
alone will not be subject to a 26a jurisdiction. However, if spoil for bank fill or bank
stabilization along the river is expected, TVA approval will be required;
¦ NCDENR, Div. of Water Quality - Section 401 Water Quality Certification application to
be submitted;
¦ NCDENR, Div. of Land Management - Land disturbance permit: permit not needed,
however, erosion control plan will be submitted;
¦ NC Department of Cultural Resources, State Historic Preservation Office - Section 106 of
the National Historic Preservation Act compliance
¦ USFWS - Fish and Wildlife Coordination Act and the Endangered Species Act (Section 7)
compliance including Takings Permit for the Appalachian elktoe population downstream of
dam;
¦ FEMA, National Flood Insurance Program - Floodplain involvement permit (Executive
Order No. 123).
6-3
Duke Power
FINAL Dillsboro Environmental / Biological Assessment
ATTACHMENTS
A-1
Duke Pmicr FINAL Dillsboro Environmental / Biological Assessment
ATTACHMENT A
REFERENCE GUIDE TO BIOLOGICAL ASSESSMENT (BA) SECTIONS
WITHIN THE ENVIRONMENTAL ASSESSMENT (EA)
A_2
Duke Power
FINAL Dillsboro Environmental / Biological Assessment
Guidance for the Location of Required BA Sections within the EA
To facilitate the review of the required BA sections within the EA document, the following table
has been developed. These noted EA sections provide the necessary BA information.
-Required BA Sections Location of Sections in EA Continents
Consultation Ilistory and Section 1.4 Identify Includes specifics of
Summary Issues Raised During USFWS consultation
Planning;
¦ Scoping and Section
4.3.4 Endangered
Species Act/Section 7
Consultation
Description of Project Section 1.0 Purpose Includes necessary
Location and Need; information on
¦ Section 3.0 Affected Project Location
Environment (with figures) and the
Applicant
Project Description ¦ Section 3.0 Affected
Environment
Affected Environment Section 3.0 Affected Includes information
and Species Accounts Environment (Section on Appalachian
3.2.3) elktoe ecology,
population, critical
habitat, and status
Effects of the Proposed Section 4.3 Includes impact
Project Environmental effects of the various
Consequences of No Action and
Dillsboro Dam Action Alternatives
on the Appalachian
elktoe o ulation
Determination of Effect Section 4.3
Environmental
Consequences of
Dillsboro Dam
Literature Cited Section 5.0 Literature
Cited
A-3
Duke Po«er
FINAL Dillsboro Environmental / Biological Assessment
ATTACHMENT B
AGENCY CORRESPONDENCE
B-1
mot: :..
Dcvinc Tarbcll & Associates, Inc.
,\u gust 23, 2003
'dir. Chris Goudreau
North Carolina Wildlife Resources Commission
645 Fish Ilatclicry Road
Marion, NC 28752-3229
400 South Ti-on Street
Suite 2401
Charlotte, N.C. 23285
Fax: [phone]
Project Number: i»00.03.00tO4.00,( )OO )O
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear Nir. Goudreau:
Devine Tarbell & Associates (D`I'A) is currently gathering, the necessary information in
association with the potential removal of the Dillsboro Dam and Powerhouse. The
c <istinZ?
Dillsboro Dam and Powerhouse are located on the Tuckasegee Rivcr in Jackson Count`,, `orth
Carolina (see attached map). Duke Power is currently preparing an Environmental Assc?;,mnicnt
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
The proposed project which is located on the Tuckasegee. River (TRAM 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists of two parts with three altcrnatiVes
each. Part One, the potential removal of the Dillsboro Dam includes: Alternative A - No lctiolt;
Alternative B - Partial Dan] Removal; and Alternative C - Complete Dam Removal. Part 1'N u,
the potential removal or conversion of the Dillsboro Powerhouse includes: Altemative A - No
Action; Alternative B --- Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with both the NE,PA Environmental Assessment and the Biological Assessment
for the Federally listed Appalachian clktoe, D"fA is required to contact the North Carolina
Wildlife Resources Commission (NCWRC) regarding the presence of any listed or proposed for
listing endangered or threatened species or associated critical habitat that may be affected by the
project. A list of the species that have been documented in Jackson County has been provided in
this letter (see attached list). This list is based on the North Carolina Natural Heritage Program
database for Jackson County. Based on this information, past studies, and past agency
consultation concerning the project area there are five known state or federal rare, threatened or
endangered (R`ITE) species located or potentially located within the project area. These species
include the North Carolina Special Concern Species wounded darter (h.thcw-!uma m hiel-atum)
and olive darter (Percina squamata) and the federal and state Endangered Species Appalachian
elk-toe (Alasmidonta mveneliaiia) acid littlewing pearlytnussel (Pegias fibula). In addition to the
above mentioned species the sicklefin rcdhorse (Afoxostoma sp. 2) also potentially occurs within
the project area.
DTA, in cooperation with Duke Power, has reviewed letters on the current and ongoing FERC
Relieensing Project for the Dillsboro Dam (FERC Project 4' 2602). at-id v,-elconmes any additional
comments and information the NCWVRC can provide concerning the potential removal of the
powerhouse and dam.
If you have any questions or need additional information please contact me at (,U4) fiilj-280S.
We appreciate your help on this matter.
Sincerely,
DEVINE T.'UWELL. S ASSOCIATES, INC.
Scott T. Fletcher, CWB, PWS
Managcr of Regulatory and Scientific Services
STF/jaw
Enclosures
cc: Pile 3»00.03.0004.00.00000
-yam
Dexine Tarbell & Associates, inc,
Atimist 28, 2001
400 South Tryon Street
Charlotte, N.C. 28285
Fax: [phone]
Project Number-. 35500.03.0004.00.00000
1',1r. John Finrle2?'Ili n
North Carolina Natural I lerit.-we Trust
NCDENR - Office of-ConsciA-ation and Comnlurlity Aff tirs
1601 Mail Service Center
Raleigh, NC 27699-1601
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear Mr. hinilcean:
Devine Tarbell & Associates (DTA) is currently _,atherl f; tile necessarv information in
association with the potential removal of the Dillsboro Dam and Powerhouse. The cxkum,
Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson County. Noith
Carolina (see attached map). Duke Power is ctuTeutly preparing an Environmental Assessillent
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted E)TA to prepare the necessary reports and permits.
The proposed project which is located on the Tuckasegee River (" RAI 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists of two parts %vith three aitenlativeti
each. Part One, the potential removal of the Dillsboro Dam includes: Alternative A - No :Action;
Alternative B -- Partial Dane Removal; and Alternative C - Complete Dam Removal. Part Two,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A - No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillshoro Powerhouse to a Museum for the Town of
Dillsboro.
Ili association with both the NEPA Environmental Assessment and the Biolouical Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact the North Carolina
Natural Herita-e Trust regarding the presence of any listed or proposed for listing rare,
threatened or endangered species or associated critical habitat, and high quality natural
communities, and Significant Natural heritage Areas that may be affected by the project. A list
of the species that have been documented in Jackson County has been provided in this letter (see
attached list). This list is based on the North Carolina Natural Heritage Program database far
Jackson County. Based on this information, past studies, and past agency consultation
concerning the project area there are five known state or federal rare, threatened or endangered
(RTE) species located or potentially located within the project area. These species include the
North Carolina Special Concerts Species wounded daricr (Etheostonra vulneratmt!) and olive
darter (Percina squansata) and the federal and state Endangered Species Appalachian elktoc
(rllasmldonta n7venrhana) and littlewrssg pearlyinussel (Pcgtas fibula). -In addition to the above
mentioned species the sicklefin redhorse (Afoxostoma sp. 2) also potentially occurs within the
project area-
DTA, in cooperation with Duke Power, has reviewed letters on the current and ongoing FERC
Relicensing Pro.icct i«r the D111shoro Dam (FERC Project 2602), and welcomes any additional
comments and infotzrsatiors the N(trth Carolina Natural I lerita-e Trust call provide concerning the
potential ren]M-al of tlsc powerhOUSe and dam.
If you have ally (Iuestimis or need additional information please contact me at [phone].
We appreciate .\our help on this matter.
Sincerely,
DEVINE TARI3ELL & ASSOCIA FS. INC.
Scott T. Fletcher, C%VB, ''S
Manager of Regulatorv and Scientific Services
STFljaw
EllclosUrOS
cc: File ')5500.0 ).0004.00.0O0OO

400 South Tryon Street
Charlotte, N.C. 28235
Fax: [phone]
Do.ine Tarbell fi Associates, Inc.
Auumst '28. 200
Project Number: 35500.03.0004.00.00000
.Mr. Mark Cantrell
USFWS-Asheville Field Office
160Lillicoa Strut
Asheville, NC. 28801
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear NIr. Cantrell:
Devine Tarbell & Associates (D-FA) is currently gathering the necessary inlbnnation in
association with the potential removal of the Dillsboro Dam and Powerhouse. Tile rsistill"
Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson County. ? cith
Carolina (see attached map). Duke Power is currently preparing an L"nvlronIIlental r1?s? :;n?cnt
and a Blolo-Tical Assessment for the potential removal of the dann and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
The proposed project which is located on the Tuckasegee River (TRM 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists ofttivo parts with three alternatives
each. Part One, the potential removal of the Dillsboro Darn includes: Alternative A - No Action-,
Altemative B - Partial Darn Removal; and Alternative C; - Complete Dam Removal. Pa t 't-wo,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A -- No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with both the NLPA Environmental Assessment and the Biological Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact the US Fish and W"Idlife
Service regarding the presence of any listed or proposed for listing rare, threatened or
endangered species or associated critical habitat that may be affected by the proiect. A list of the
species that. have been documented in Jackson County has been provided in this letter (sec
attached list). 'I his list is based oil the North Carolina Natural Heritage Program database for
Jackson County. Rased on this information, past studies, and past agency consultalion
concerning the project area there arc two known federal rare, threatened or endangered (RT1)
species located or potentially located within the project area. These species include the federal
Endangered Species Appalachian elk-toe (Alasmidonta iwveneliema) and littlewing pearlytnussel
(Pcg-gus fibula). In addition to (lie above mentioned species the sicklefin redliorse (1lloxostoma
sp. 2) also potentially occurs within the project area.
DTA, in cooperation with Duke Power, -has reviewed letters on the current and ongoing FERC
Relicensing Project for the Dillsboro Dam (FERC Project 112602), and welcomes any additional
comments and information the USFWS can provide concerning the potential removal of the
powerhousc- and dart.
If you have any questions or need additional information please contact me at (704) S05-2808.
%V apl)I-Mate your help on this matter.
Sincerer',
DEVINE TARBELL &- ASSOCIATES, INC.
Scott T. Fictchcr, CWB, PWS
Manager of Rcgulatory and Scientific Services
STF%jaw
Enclosures
cc: File ?500.Oz.Ot104.00.c)C)Ot)0
D -n4
.'.
Devine Tarhell & Associates, Iuc.
Allg,ust 28, 2003
`Ir_ David Brook
Administrator, State Historic Preservation Office
Deputy State Historic Preservation Officer
4617 Mail Service Center
Raleigh, NC 27699-4617
400 South Tryon Street
Charlotte, N.C. 28285
Fax: [phone]
Project Number: 35500.03.0004.00.00000
Subject: Information Request Concerning Potential Dillshoro Dain Removal
Dear Mr. Brook:
Devine Tarbell S-- Associates (DTA) is currently gathering the necessary information in
association with the potential removal of the Dillsboro Darn and Powerhouse. Tltc c\istill2
Dillsboro Dam and Powerhouse are located on the'I'uckasegee River in Jackson County, '1olth
Carolina (see attached map). Duke Power is currently preparing an Environmental Assessment
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
The proposed project which is located on the Tuckasegee River (TRIM 31.7) adjacent to the
Town of Dillsboro. Jackson County, North Carolina, consists of two parts with three alternatives
each. Part One, the potential removal of the Dillsboro [)am includes: Alternative A - No Action;
Alternative B -- Partial Dam Removal; and Alternative C - Complete Dam Removal. Part Two,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A -- No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a IMuseum for the To%vn of
Dillsboro.
In association with both the NEPA Environmental Assessment, DTA is required to contact the
State Historic Preservation Office regarding the presence of any archaeological or historic sites
within the project area. Based on a letter received from your office dated December 16, 1999
there are no known archaeological sites located within the floodpool or shoreline of the Dillsboro
Reservoir or likely to be found there. In 2001 the Project stnictures were assessed for their
eligibility for inclusion on the NRHP (Thomason and Associates 2001). Each stnicture was field
inspected to determine its components, to evaluate Its architectural or engineering* significance, and
to assess its degree of integrity. Extensive historical research was conducted oil these hydroelectric
facilities and the overall history of hydro-power in the state, at the archives of Duke Power in
Franklin, North Carolina, and at the State Archives in Raleigh.
The Project consists of a powerhouse and darn originally built in 1913. The Project lacks sufficient
integrity to meet NRIIP criteria. Although the original powerhouse and darn were built in 1913,
both were extensively modified in 1958. Due to extent of these alterations, neither the powerhouse
nor dam meet NRI IP requirements.
The NRI-iP assessment report stating that none of the Project structures is eligible for the NRIIP
was submitted to the NCSHPO on November 8, 2001. Duke has not received any comments on
the recommendation to date.
D"I'A, in cooperation with Duke PoNver, has reviewed letters on the current and on1-1 FLRC
Relicensing Project for the Dillsboro Dam (FERC Project .' 2602), and welcomes any additional
comments and information the State Historic Preservation Office can provide concerning the
potential removal of the powerhouse and dam.
If you have any questions or need additional inf'onnatior please contact nle at [phone].
We appreciate your help on this matter.
Sincerely,
DEFINE TAR ELL fi ASSOCIATES, INC.
Scott T. Fletcher, CWR, P%VS
NI.mager of Rcoulatorv and Scientific Scn ices
STFJaw
Enclosures
cc: File 35500.03.0004.00.00000

nninc Tarbell & Associates, Inc.
lr.. acn,5ucna,?., t 41;,4 ..n.;.n.:.i-
Au(,ust 28, 2003
Mr. Steve Reed
NCDENR-DWR
Archdale Building- I 1 `" Floor
512 North Salisbury Street
Raleigh, NC 27604
400 South Tryon Street
Suite 2401
Charlotte, N.C. 28285
Fax: [phone]
Project Number: 35500.03.0004.00.00000
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear Mr. Reed:
Devine Tarbell Associates (DTA) is currently gathering the necessary in ormation in
association with the potential removal of the Dillsboro Dam arid Powerhouse. The Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson Count, \orth
Carolina (see attached map). Duke Power is currently preparing an Environmental Assessment
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
The proposed project which is located on the Tuckasegee River ("TRIM 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists of two parts with three altcnmtives
each. Part One, the potential removal of Tile Dillsboro Dam includes: Alternative A - No Action;
Altenlative 13 - Partial Dam Removal; and Alternative C - Complete Dam Removal. Part Two,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A -- No
Action; Alternative B - Demolition arid Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the 'T'own of
Dillsboro.
In association with both the NEPA Environmental Assessment arid the Biological Assessnent
for the Federally listed Appalachian elktoe, DTA is required to contact the North Carolina
Department of Environment and Natural Resources - Division of Water Resources (NCDENR-
DWR) regarding any potential water resource issues.
DTA, in cooperation with Duke Power, has reviewed letters on the ctrr-rent and ongoing FERC
lZelicensing Project for the Dillsboro Dam (FERC Project 4 2602), and welcomes any additional
comments and information the NCDENR-DWR can provide concerning the potential removal of
the powerhouse and darn.
If you have any questions or need additional information please contact me at (704) 505-2SO8.
We appreciate your help on this matter.
Sincerely,
DEVINE TARBELL kC ASSOCLATES, INC.
Scott T. Fletcher, CWB, PPS
Manager of Regulatory and Scientific Services
s,mj aw
Enclosures
cc: File 35500.03.0004.00.00000
Devine Tarbett & Associates, Inc.
?:u.+•v:en?li.? av.,Scxmu.., /;, kc;Jn.n?S;,ca:..n
August 28, 2003
Project Manager (Jackson County)
Asheville Regulatory Field Office
US Army Corps of Engineers
151 Patton Avenue, Room 20S
Asheville, NC 28801-5006
400 South Ti-yon Street
Suite 2401
Charlotte, N.C. 28285
Fax: [phone]
Project Number: 35500.03.0004.00.00000
Subject: Information Request Concerning Potential llillsboro Dam Removal
Dear Project Manager:
Devine Tarbell & Associates (DTA) is currently gathering the necessary inforniation in
association with the potential removal of the Dillsboro Dam and Powerhouse. The cristing
Dillsboro Dam and Powerhouse are located on the 'fuckasegee Rivet' in Jackson County, North
Carolina (see attached map). Duke Power is currently preparing in Environmental Assessment
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted D,rA to prepare the necessary reports and permits.
The proposed project which is located oil the Tuckase-ee River (TRIM 31.7) adjacent to the
Town of llillsboro, Jackson County, North Carolina, consists of two parts with three altcrnativcs
each. Part One, the potential removal of the Dillsboro Dain includes: Alternative A - No Action;
Alternative B - Partial Dam Removal; and Alternative C - Complete Dam Removal. Part Two,
the potential removal or conversion of the llillsboro Powerhouse includes: Alternative A - No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with the NEPA Environmental Assessment, DTA is required to contact the US
Army Corps of Engineers (ACOE) regarding the presence of any wetlands or waters of the
United States that may be affected by the project. Based on previous studies conducted Within
the project area there are no known wetlands that would be potentially affected by the project.
However, the project is located within (project dam) and on the shoreline (project powerhouse)
of the Tuckasegee River. Actions within this area will potentially require a pennit firoin the
ACOE.
DTA, in cooperation with Duke Power, has reviewed letters on the current and onvping FERC
Relicensing Project for the Dillsboro Dam (FERC Project T 2602), and welcomes any additional
comments and information the ALOE can provide concerning the potential removal of the
powerltiouse ;tnd dani.
If you have any questions or need additional information please contact me at (704) 805-2SOS.
We appreciate your help on this matter.
Sincerely,
DEVIN-E TARBEL_L ?C ASSOCIATES, INC.
Scott T. Fletcher, CWH, PWS
Manager of Regulatory and Scientific Services
STFijaw
Enclosure,
cc: File 3500.03.0004.00.00000
Devine Tarhell & Associates, Inc.
August 28, 2003
Mr. Mike Bolt
Eastern Band of Cherokee Indians
Qualla Boundary Reservation
Council House
PO Box 455
Cherokee, NC 28719
400 South Tryon Street
Charlotte, N.C. 28285
Fax: [phone]
Pro.jcct Number: »i)(l.t);.0Ut?-:.00.00O1?0
Subject: Information Request Concerning Potential Dillsboro Dain Removal
Dear N1r. Bolt:
Devine Tarbell &, Associates (DTA) is currently gatherings the necessary information in
association with the potential removal of the Dillsboro Dam and Powerhouse. The c?Asting
Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson County. North
Carolina (see attached map). Duke Power is currently preparing an Environmental Asscssmcnt
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
'hhe proposed project which is located on the Tuckasegee River (TRIM 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists of ti vo parts with three alternatives
each. Part One, the potential removal of the Dillsboro Dam includes: Alternative A - No Action;
Alternative B - Partial Dam Removal; and Alternative C - Complete Dam Removal. Pert Two,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternativc A No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative.
C - Restoration and Conversion of the Dillsboro Powerhouse to a 'Museum for the Town of
Dillsboro.
In association with both the N`EPA Environmental Assessment and the Biological Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact the Eastern l3and of
Cherokee Indians regarding the presence of any species important to the Eastern Band of
Cherokee Indians or associated critical habitat that may be affected by the project. A list oi'the
RTE species that have been documented in Jackson County has been provided in this letter (see
attached list). This list is based on the North Carolina Natural Heritage Program database liar
Jackson County. Based on this inforniation, past studies, and past agency consultation
concerning the project area there are txvo known federal rare, threatened or endangered (RTE)
species located or potentially located within the project area. These species include the federal
Endangered Species Appalachian clktoe (Ala.smidonta ravencliana) and littlewing pearlyinusscl
(Pcgias fihrrla). In addition to the above mentioned species the sickleiin redhorso (Afoxostoma
sp. 2) also potentially occurs within the project area. We are also contacting the I BCI for any
information or comments regarding the potential for additional cultural resource affects dtic to
the potential dam removal and subsequent exposure.
DTA, in cooperation with Duke Power, has reviewed letters oil the current and ongoing FERC
Reliccnsing Project for the Dillsboro Dane (PERC Project ' 2602), and welconics any additional
comments and information the Eastern Bared of Cherokee Indians can provide concenilmi the
potential removal of the powerhouse and dam.
If you have any questions or need additional information please contact me at (704).805-2808.
We appreciate your help on this matter.
Sincerely,
DEVINE TARBELL Sr. ASSOCIATES, INC.
Scott T. Pletcher, CWB, IMIS
Manager of Rev',ulatory and Scientific Services
STF/jaw
Enclosures
cc: Pile 35500.03.0004.00,0000 0
^1w_
Uevinc Tarbcll & Associaucs, Inc.
Auoust 28, 2003
Ms. Jean Ilartbamer
Dillsboro Mayor
42 Front Street
Dillsboro, NC 2872_-
400 South "rryou Street
Suite 2401
Charlotte, N.C. 28285
Fax: [phone]
ProjL-ct Number: 35500.03.0004.00.00000
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear -Mayor Hartbareer:
Devine Tarbell & Associates (DTA) is currently gathering the necessary information in
association with the potential removal of the Dillsboro IDnr arid Powerhouse. The- exi:,tim,
Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson County. \Turth
Carolina (see attached map). Duke Power is currently preparing an Environmental Assc::_.n;cnt
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and penults.
The proposed project which is located on the Tuckase0ee l'\ivcr (TRIM 31.7) adjacent to the
Town of Dillsboro, Jackson County; North Carolina, consists of two parts with three 11tcr-mitivcs
each. Part One, the potential removal of the Dillsboro Dam includes: Alternative A - No Acti011;
Alternative B - Partial Dam Removal; and Alternative C - Complete Darn Removal. fart I wo,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A - No
Action; Alternative B -Demolition and Disposal of tiro Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with both the NEPA Environmental Assessment and the Blolo,-lcal Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact local officials including
the Dillsboro Mayor regarding any comments or additional i it'6miatlon concerning the potential
dam and powerhouse alternatives.
Based on a letter received from the State Historic Preservation Office dated December 16, 1999
there are no known archaeological sites located within the floodpool or shoreline of the Dillsboro
Reservoir or likely to be found there. (n 2001 the Project structures were assessed for their
eligibility for inclusion on the NRI IP (Thomason and Associates 2001). Each structure was field
inspected to determine its components, to evaluate its architectural or engineering significance, and
to assess its degree of integrity. Extensive historical research was conducted on these hydroelectric
facilities and the overall history of hydro-power in the state, at the archives of Duke Power in
Frank=lin, Nortlt Carolina, and at the State Archives in Raleigh.
The Project consists of a powerhouse and dam originally built in 1913. The Project lacks sufficient
integrity to meet NRIIP criteria. Althoug}n the original powerhouse and darn were built in 1913,
both were extensively modified in 1 X15 Due to extent of these alterations, neither the powerhouse
nor dam meet NRI IP requirements.
The NRIIP assessment report stating, that none of the Project structures is ell-gible for the NRHP
was submitted to the NCSI IPO on November 8. 2001. Duke has not received any comments on
the recommendation to date.
DTA, in cooperation with Duke Power, has reviewed letters on the current and ongolm, FERC
Relicensing Project for the Dillsboro Dam (FFRC Project T 2602), and welcomes any additional
comments and information the Office of the il4ayor can provide concerning the potential
powerhouse and dam altcruatives.
If you have any questions or need additional information please contact tine at [phone].
We appreciate your help on tills matter.
Sincerely,
DEVINE TARBEI.I_ & ASSOCIA` I-S, INC.
Scott T. Fletcher, CWB, PWS
Mana-cr of Reuulatory and Scientific Services
STF/jaw
Enclosures
cc: File 35500.03.0004.00.0000C?
? ...:b.
Devine Tarhell S Associates, inc.
AIIgLl9t 28, 2003,
Mr. Kenneth W'cstnioreland
Jackson County iktanai ' cr
401 Grindstaff Cove [\oad
5ylva, NC 28770
400 South Tryon Street
Suite 2401
Charlotte, N.C. 28285
. Fat: 704 805 2778
Project Number: 35500.03.0004.00.00000
Subject: Information Request Concerning Potential Dillsboro Dam Removal
Dear Mr. Westmoreland:
Devine Tarbell & Associates (DTA) is currently gathering the necessary Lnfonllation in
association with the potential removal of the Dillsboro Darn and Powerhouse. The cxlslim)
Dillsboro Dam and Powerhouse are located on the 'I'tlckasegee River in Jackson Comity, Nt?rili
Carolina (sec attached map). Duke Power is currently preparing an Environmental Assessnent
and a Biological Assessment for the potential removal of the dam and powerhouse and has
contracted DTA to prepare the necessary reports and permits.
The proposed project which is located on the "fuckasegce River JRM 31.7) adiacent to the
Town of Dillsboro, Jackson County, North Carolina, consists of two parts with three alternatives
each. Part One, the potential removal ofthe Dillsboro Dam includes: Alternative A - No Action;
Alternative B -- Partial Dam Removal; and Alternative C -- Complete Dam Removal. Part 1-wo,
the potential removal or conversion of the Dillsboro Powerhouse includes: Alternative A --- No
Action; Altemattve B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with both the NF,PA Environmental Assessment and the Biological Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact local officials including
the Jackson County Manager regarding any comments or additional information concerning the
potential dam and powerhouse alternatives.
Based on a letter received from the State Historic Preservation Office dated December 16, 1999
there are no known archaeological sites located within the floodpool or shoreline of the Dillsboro
Reservoir or likely to he found there. In 2001 the Project structures were assessed for their
eligibility for inclusion on the NRHP (Thomason and Associates 2001). Each structure was field
inspected to determine its components, to evaluate its architectural or engineering significance, and
to assess its degree of integrity. Extensive historical research was conducted on these hydroelectric
facilities and the overall history of hydro-power in the state, at the archives of Duke Power in
Franklin, North Carolina, and at the State Archives in Raleigh.
The Project consists of a powerhouse and dam originally built in 1913. The Project lacks sufficient
integrity to meet NRIT criteria. Although the original powerhouse and clam were built in 1913.
both were extensively modified in 1958. Due to extent of these alterations, neither the powerhouse
nor dam meet NRIFP regmi-cnnents.
The MUM assessment report stating that none of the Project structures is eligible for the NR-HP
was submitted to the NCSIIP(i oil November 3, 2001. Duke has not received any comments on
the recolm endatzoil to date.
DT.,V in cooperation with Duke Power, has reviewed letters on the current and ongoing.; FERC
Relicerrsing Project for the Dillsboro Dam (FERC Project 9 2602), and welcomes any additional
comments and information Jackson County can provide concerning the potential powerhouse
and damn alternatives.
If you have any questions or need additional information please contact nnc at [phone].
N e appreciate your help on this matter.
Sincerelv,
DEVINE TARf3E1-1, & ASSOCIATES. INC.
Scott T. Fletcher, CWB, PWS
Manager of Regulmory and Scientific Services
STF/jaw
Enclosures
cc: File 35500.03.0004.00.00000
111\\\{{{1???a .y?•i.`??_
Do-ine Tarbell & Associate-, Inc•
Alli;llst 2?5, 2003
,Ms. Brenda Oliver
Town of Sylva
I 1 Allen sti-cet
Sylva, NC 28779
400 South Tryon Street
Suite 2401
Charlotte, N.C. 28285
Fax: [phone]
Project Number: 3»00.03.0004.00.00000
Subject: Information Request Concerning; Potential Dillsboro llam Removal
Dear (\1s. Oliver:
Devine Tarbell &- Associates (DTA) is currently gathering the necessary information in
association with the potential removal of the Dillsboro Dam and Powerhouse. The ;istin J
Dillsboro Dam and Powerhouse are located on the Tuckasegee River in Jackson Count,,-, :,11orill
Carolina (see attached neap). Duke Power is currently preparing an Environmental Ass: .?smcnt
and a Biological Assessment ('or the potential removal of the dam and powerhouse and has
contracted DT.k to prepare the necessary reports and pennlits.
The proposed project which is located on the Tuckasegee River (TRM 31.7) adjacent to the
Town of Dillsboro, Jackson County, North Carolina, consists oftwo parts with three alternatives
each. Part One, the potential removal of the Dillsboro Dam includes: Alternative A - No Action.,
Alternative B -- Partial Dam Removal; and Alternative C - Complete Dann Removal. Part Two,
the potential removal or conversion of tine Dillsboro Powerhouse includes: Alternative A - No
Action; Alternative B - Demolition and Disposal of the Dillsboro Powerhouse; and Alternative
C - Restoration and Conversion of the Dillsboro Powerhouse to a Museum for the Town of
Dillsboro.
In association with hotln the NEPA Environmental Assessment and the Biological Assessment
for the Federally listed Appalachian elktoe, DTA is required to contact local officials including
representatives of' the Town of Sylva regarding any comments or additional information
concerning the potential dam and powerhouse alternatives.
Based oil a letter received from the State Historic Preservation Office dated December Iii. 1999
there are no known archaeological sites located within tine iloodpool or shoreline of the Dillsboro
Reservoir or likely to be found there. In 2001 the Project strictures were assessed for their
eligibility for inclusion oil the NRI-IP (Thomason and Associates 2001). Each structure was field
inspected to detemime its components, to evaluate its architectural or engineering significance, and
to assess its degree of integrity. Extensive historical research was conducted on these hydroelectric
facilities and the overall history of hydro-power in the state, at the archives of Duke Power in
Franklin, North Carolina, and at the State Archives in Raleigh.
The Project consists of a powerhouse and danl originally built in 1913. The Project lacks sufficient
integrity to meet N]Z.1-I1' criteria. Although the original powerhouse and dam were built in 1913,
both were extensively modified in 1958. Due to extent of these alterations, neither the powerhouse.
nor dam meet NRHI' requirements.
Tile NRHP assessment report statin;, that none of the Project structures is eligible for tile NRHP
%vas submitted to the NCSHPO on November S, 2001. Duke has not received any comments on
the reconllnendation to date.
DTA, in cooperation with Duke Power, has reviewed letters oil the current and ongoing FERC
Relicensing Project for the Dillsboro Dam (FERC Project rt 2602), and welcomes any additional
comments and information the Town of Sylva can provide concerning the potential powerhouse
and darn alternatives.
If you have any questions or need additional inforinatlon please contact me at [phone].
We appreciate your help on this matter.
Sincerely,
DEVINE TAIWI LL & ASSOCIATES, INC.
Scott T. Fletcher, CWB, PWS
Manager of Regulatory and Scientific Sei- ices
SITJaw
Enclosures
cc: rile 35500.03.0004.00.00000
x
li
rlhc.gfonorabfe I,eoft D. Jones, l'ri upabCfnef
qheHorwradfeCarroll? Crowe, Vice-61ief
fib Blurikeriship
Chairman
i cllo.vilill "ro.cnship All ust 1 S. 200"
Lar7'U 131yi1re'
i lee Cf1r:iY7t71'` Devine Tarbell & Associates, Inc
lti'ollto•srl Trncnsiuc
400 South Tryon Street, Suite 2401
Charlotte NC 28285
r1L:11 CoC1RC1I MUT11',ets
-t?sa I3rcut(i y AIc(.-by Subject: Information Request Concerning Potential Dillsboro Dam Removal
Sig C!ne Township
Richard (loather Dear Mr. Fletcher:
lit; Cove TowTiship
Jinn vtole 'This letter concerns the Dillslxuo Dam and Powerhouse area of potential effect
'1l.rcltrnvn'}bu•ns}tip (APE). After our discussion with Mike Bolt as the Tribal Stakeholder
Representative he concurs with our office that an on site meeting is warranted.
Albert Crowe
irdlf-wn Trnrnship The EBCI= I'I-IPO would appreciate you contacting our office by letter, telephone
or email for this meeting. You may contact me at 828497-1588 or email
lcuic? L Jwttiltt_51;ct loratavlCr?nc-cherokee.com the THPO Assistant for the best time to meet at the
'o inttowa 'rug. n?`lip
Dillsboro Dam site.
1 ommye Saanook(? Sincerely,
?'ainttc» ?z1 Townshil} _
61unda Sanders
strowhird tt Lora K. o- Taylor
lerokee. Co, Tolt715hi}i
•,)renda L. Norville
SnUtSI)ir'l3 ii
_ letu}:ee i:o. "1"ox-tisllip
Divaylle Jackson
Wolfero\vn 'iouwnshrp
Akin 13. E'nslcy
Yellotvilill "T?)u'nsl-lip
Cc: Mike Bolt
88 Council House Loop • P.O. Box 455 • Cherokee. I.C. 28719
Telephone: [phone] or 497-7000
Telefax: [phone]
111'; ,ll,dU11!LU .11 1J:zIIL .ti U9. ??L R6.?ls .R.PaLvUIii L=J
Eastern Band of Cherokee Indians
Tribal Historic Preservation Office
P.O. BX 455
Cherokee NC 28719
September 9, 2003
het: Duke Power Facility Millsboro Dam
Dear Jolut NVishon:
This Icttcr will concern the visit to the Duke Powcr plant in Dillsboro, on
September 8, 2003; in Not111 Carolina. It is our understanding the Millsboro Dam.
will be renloved slowly from top to bottom allowing for silt to be moderately
disbursed instead of all at one time. Please correct me if i have miss understood this
phase of the silt removal. As the TI IPO of the EBCI our main concerns are that of heavy
equipment on the property and damage that this may cause to possible sites.
The EBCI '111110 has concerns of silt washing down the river and would appreciate Duke
Power taking what ever pleasures to minimize this adverse effect. Moreover, we are
concerned with of heavy equipment that may be on site and will cause ground
disturbance while moving about an area for any time allotted to the project. We would
like to reconnmcnd finding an area that your equipment that will not cause excessive
weight damage with in this area of potential effect (APE). In addition, an
archaeological survey of the API, needs to be completed by a Department of Interior
(DOI) qualified Archaeologist. We ,vould like to know ]low much disturbance to the
APE will occur during construction.
Mr. Wishon, the EBCI '1'11110 highly recommends that an archacologist be placed
on site to monitor ground disturbance activities at all times during constriction. In
addition to an archaeologist on site we are recommending that security be placed to watch
for looters whom will find this to be a perfect opportunity for mischief activity. "I11c
utmost confidentially from Duke Power concerning these requests will be most
appreciative because of the potential sensitivity of the area. Once the darn removal has
been accomplished this is when we would request a completion pedestrian archaeological
survey initiated earlier to occur within the river APE. Securing embankillents as
discussed is an addition concern; we would like to see that hydro seeding is
accomplished as we spoke of during our visit. As you mention river cane would be a
possibility and recommended. As for stabilization efforts the river cane, which was
natural cane to this area and important to be Cherokee people to collect and gather, the
1c13CI THPO feels that this would be a good solution to planting oil banks.
Sincerely,
Lora Taylor- EBCI TI IPO
RECEIVED
S E P 15 2003
North Carolina Department of Cultural Resources
State Historic Presen-ation Office
David L. S. 13rcwk, Administrator
Michael F. Easley. Cnwernor Division of Historical Rescurces
Lisbeth C. Evans. Secretar:
Jeffrey J. Crow. Deputy Secretary
OfEce of Archives at:d Historv
September 10, 2003
Scott T. Fletcher
Devine Tarbell & :Associates, Inc.
400 S. Trion Street, Suite 2401
Charlotte, NC. 28285
Re: Potential Dillsboro Dam Removal, Jackson County, I?R03-2109
Dear Mr. Fletcher:
Thank N-ou for your letter of !August 28, 2003, concerning the potential removal of the
Dillsboro Dam and Powerhouse by Duke Power. We recently completed a conference call
«7th Jentufer Huff of Duke Energy and Phil Thomason, Duke's historic resources consultant.
In that conversation we stated that we believed the IDillsboro Dam and Powerhouse are
eligible for listing in die National Register of Historic Places under Criterion A. We also noted
that, even though the property appears to be eligible as a collection of structures related to the
early lustory of hydroelectric generation in western North Carolina, we are not opposed to the
removal of either structure.
Removal of either or both of the structures would constitute an adverse effect upon a
National Register-eligible historic property and require consultation under Section 106 of die
National Historic Preservation Act. Discussions with I\fs. Huff and J. T, Griffin with FERC
indicated that there were at least two procedural options for handling; the removal of the
stnicrures. We look fomard to exploring these options in further detail with Duke power and
to receipt of the final eligibility report for the Dillsboro Dam and Powerhouse.
The :above comments are nlade pursuant to Sccdon 106 of the National Historic Preservation
Act and the Advisory Council on Historic Presentation's Regulations for Compliance with
Section 106 codified at 36 CFR Part 800.
wNsw,hno.dcr.state.nc.us
Location ltailing address relcphoncii, a%
ADMINISTRATION :0' N Blount St.. Rakich NC 4617 ;Llail Sentce Center. Raleigh NC 27n994617 [phone] • 733- 653
RESfOR.1170N 515 N. Blount St, Raleigh NC 4617 Mail Service Center. Raleigh NC 27699-4617 [phone] . 715-4801
SURVEY S PLANNING 515 N. Blount St.. Raleigh NC 4617 Mail Serrt.e Ccntcr, Raleigh NC 276994617 [phone] • 715-4801
Page 2
Thank you for your cooperation and consideration. If you have questions concerning the
above comment, contact Renee GIedla-h--:arley, environmental reviexv coordinator, at
919/733-4763. In all future conunum cation concertung this project, please cite the above
referenced tracking number.
`uucercly,
:avid Brook
cc: Jennifer I tuff, Ihtkc Power
J. T. Griffin, FrRC:
Pill hhotllasotl, I11ntI]:1soil & :Associates
Ala .??
CDENR
North Carolina Department of Environment and Natural Resources
Michael F. Easley, Governor William G. Ross Jr., Secretary
12 Ausiust 200;
INIT. Scott T. Fletcher
Devine Tarbell & Associates, hic.
400 South Tryon Street, Suite '2401
Charlotte. NC ?S%$
Subject: hif'orrnation request for Dillsboro 1-)am IZentOv<rl Project; Jackson County
Dear NIr. Fletcher:
The Natural I leritage Program has a priority natural area directly within the project site. ;1
sig,nificrnlt natural heritage area is an area of land or water identified by the NC Natural Heritage
Program (NTHI') as being important for protection of the State's biodiversity. Significant uat?iral
heritage areas contain one or mare Natural Heritage elements -- high-quality or rare natural
cotlliiiiinittes. rare species, and special aninial habitats. The nationally significant Tuck.,;5cswe
River Aquatic I labitat will be impacted by this project.
In addition, our Program has records of five rare animals in the river near the dam remrn,,ai site.
The federal and state endangered Appalachian elktoc (Alasmidonta 1"1-11'elleli(7714). the, federal and
state species of special concern Olive darter (Perches squarnata) and Hellberider
(Cri7)tohranchus alle-c7niensi.s), the state special concern Navy-rayed lampmussel (Lanj)sd7.?
firs4iola) and \Voutided dailer (E-theostoma tiulneralum), are found in Ilse river both ul)5trc:arl anti
downstream of the site. Because of the presence of these species, it is imperative that strict
precautions be taken, and all threats to the species be addressed prior to removal.
Please let the know it 'l can provide more information. The North Carolina Natural Herita e
Program looks forward to a collaborative effort to help protect the State's natural diver:5ity. if
cart be of assistance, please do not hesitate to call me at 919-715-1751.
riccrcIV,
", , ? F- -
Sarah E. McRae. Freshwater Ecologist
Natural HeritaLe Program
SENT sem
1601 Mail Service Center, Raleigh, North Carolina 27699-1601
Phone: [phone] FAX: [phone] Internet- wwrw.enr.state. nc.uslENR
An Equal t]pportundy 1 Atf;rma:i.e Amn Employer - 50;o Recycled,, 10`'/ Pest Consumer Paper
O( YVn lF9 ` whacl F. Easley. GOVerr.Ar
r Q
William G. Ros; 1r_ seerenry
6L)S - 2-7 79 Nortb C aol;ni Deparnner t of En%ironaen! and t a!Ud Re;ourees
Alan A'. UM- Y. E. Dire:tar
Di%i:ion of water Quahty
Ccleen H Sull:n;. Decry D1rer1,;r
Divisiua of Na:cr Qaabzy
5 Al12usi, 200
Mr. Jeffrey G. Lineberger
Manager, Hydro Licensing
Duke Power Company
526 South Church Street
Charlotte, North Carolina 28201-1006
Dear 1\'Lr. Lineberger,
Thank you for your lcttr~r concerning the 401 CciIification of this project and removal of the Dillsbcro
dam on the Tuckasegee River (DWQ # 03 0179). As you may }.now the Division of Water Quality (DWCI)? i., ;,l
active member of a multiapency task force which is studyinb the mitigation protocols for dam removal. Policy
regarding this activity has been recently written and is been reviewed by members of the task force.
Implementation of any guidelines concerning the removal of the Dillsboro darn may become part of DWQ's
comments regarding this 401 certification. We respectfully request that DWQ personnel be included on the
following Technical Leadership Teams; Botanical Survey, Fish Survey, Fish Instream Flow Sur vev. Dish
Passage Feasibility Study, Riparian Habitat Protection, Alacroinvertebrate Survey, and Sediment lvlanagement
Plan (Kevin Barnett With the Asheville Regional Office of DWQ is currently on the Temperature and Dissolvcd
Oxygen Survey and Point Source Inventot}• Teams). Time commitments of D«'Q personnel may be limited to
email conferences and/or report review. Please contact Dave Penrose of my staff for snore information
regarding these reviews (dave.penrose C?ncmaiLnet or 919/715-3481).
It should also be noted that monitonnp
., requirements for die assessment of successful removal of dams in
North Carolina are included as part of the current mitigation policy. These protocols are still being reviev-led by
the task force; however, a four or five year monitoring plan is being suggested at this point. A typical
monitoring plan would include a pre-removal investigation to determine baseline conditions and at least three
years of post-removal monitoring. In your July 3 letter you note that a two-year post-removal stream
remediation and monitoring is suggested as part of this project. This monitoring requirement will need to be
revisited as part of the monitonne phut for this project.
CC
Kevin Barnett, Asheville Regional Office
Dave Penrose, Central Office
Jimmie Over-ion,Envir? imental Sciences Brar .h A{rQt
izb N?R
N C. Division cf water Quality, 401 1vcaands Ccmficauon Unit.
1650 Afar) Smicc Center. Ral:ugh. NC 27699•I6110(M2tltag Address)
2321 Cnbcrec ffi d.. Raleigh. !.C 276V,-2:60 tLxauon;
[phone] (,boric), 919.733-6&93 (fu).

FLETCHER Scott T
From: Chris Goudreau [[e-mail])
Sent: Friday, August 29, 2003 5:34 PM
To: Cantrell, Mlark; Johnson, Steve; Fletcher, Scott; Barnett, Kevin; [e-mail]
Subject: Dillsboro draft sediment report
I know you guys wanted this two weeks ago, but here's some feedback on tic Dillsboro scdilitent report.
-----Original Message-----
From: David L. Yow [mailto:yowdl(a carthlink.net)
Sent: Thursday, August 07, 2003 10:46 AM
To. ' IMS Goudreau'
Cc: N'lartin, Mallon ,, Anderson, Owen F.; Besler, Doug; Fraley, Steve ; hittel, Call. l.ofiis, Scot(; 'Wheeler.
Powell'
Subject: I2E-: draft sediment report
Chris,
I'm not much of a sediment expert either. Ili general, I third; the impacts of sediment release from f)i1f hr. r ,"rill
be short-term compared to the permanent improvement in habitat connectivity tar aquatic launa.:' I)y I:tt, nt
hydrocarbons or heavy metals will just work their way down into Fontana: I 1-IuCss 1 share Al-10 (41thi i?:'S Vicw
that one big pile of garbage is better than two little ones (or in this case. one big one and one little one,).
If anything, we might have asked for some small level of toxicological monitoring in the lower Tuck in thr first
couple of years following dam removal, possibly using tissues froni SN413 and a bottom feeder (redhoi ;c r
channel cat) as an indicator of any problems. All of this is probably moot if the levels of toxins ;rents
don't exceed accepted thresholds. I've never heard of a consumption advisors, for nickel, which sucmt , tltc
only material that raised a flag in any of their tests. Basically, it looks like the dint is not much more of a l?tng-
terni toxin sink than any other large pool in the river.
-David
JEAN HARTBARGER
MAYOR
Jim Cochran.
Vice Mayor
Board Members.
M,ary Bumgarner
Lela Jean PhiMPs
Bud Smith
Emma Werlen Bcrg?r
August 12, 2003
"Heart of Great Smokies Vacationland"
Mr. Scott T. Fletcher, CW13, PWS
Devine Tarbell & Associates
400 S. Tryon St., Suite 2401
Charlotte, NC 28285
Dear Mr. Fletcher:
HERBERT LAN
TOWN CLERK
At this point and time the Town of Dillsboro has conceded to the
complete removal of the Dillsboro Dam if so determined by Duke
Power, though this was not our first choice. In addition, if the removal
of the dam is made we would desire the demolition of the
Powerhouse along with the complete dam structure.
The Town is very interested in the plans for the removal and
restoration of the banks of the Tuckasegee River, both above and
below the dam and what impact the sedimentation currently built up
above the dam, will have on the river below upon the dam's removal.
We will expect to be kept informed of plans before action is taken and
the effects revealed after removal.
The town does appreciate this opportunity for input on this matter.
Sincerely,
Jean Hartbarger,
Mayor
P.O. Box 1088 Dillsboro, North Carolina 28725 Phone: [phone] Fax: [phone]
Duke Power
FINAL Dillsboro Environmental / Biological Assessment
ATTACHMENT C
SITE PHOTOGRAPHS
C-1
Duke Power DRAFT Dillsboro Environmental / Biological Assessment
Duke Power DRAFT Dillsboro Environmental / Biological Assessment
Duke Power DRAFT Dillsboro Environmental / Biological Assessment
Duke Power DRAFT Dillsboro Environmental / Biological Assessment
Duke Power
FINAL Dillsboro Environmental / Biological Assessment
ATTACHMENT D
ENVIRONMENTAL ASSESSMENT SIGNIFICANCE CHECKLIST
D-1
Duke Po%%er
FINAL Dillsboro Environmental / Biological Assessment
ENVIRONMENTAL ASSESSMENT SIGNIFICANCE CHECKLIST
This checklist is intended to help determine whether a given alternative would affect
environmental features of special legal or policy significance that should be discussed in an
analysis document.
WOULD IMPLEMENTATION OF'TIIE ALTERNATIVE BE EXPECTED TO AFFECT:
1. Federally listed threatened or endangered species or their critical habitats? Yes-
Appalachian Elktoe
2. Properties either listed in or eligible for listing in the National Register of Historic
Places? Yes-Dillsboro Powerhouse. However, NCSIIPO not opposed to removal
with appropriate documentation of historical context
3. Result in either surface or subsurface disturbance? Yes, both upland and stream
channel disturbance due to dam removal activities
4. Loss or alteration of natural wetlands that would adversely affect biological productivity,
habitat diversity, flood storage capacity, or aquifer recharge capacity? No wetlands in
the project area
5. Areas within the 100-year floodplain, in terms of increasing the flood hazard potential?
Activities are within the 100-year floodplain but no increases in flood hazard
potential are expected
6. Natural resources within officially designated boundary of the State coastal zone? No
7. Discharges of dredged or fill materials in waters of the U.S. or adjacent wetlands? Yes.
Waters of the U.S (Tuckasegee River) discharge associated with demolition of the
dam and possibly the powerhouse
8. Structures or facilities within, under or above a navigable waterway? No
9. River segments designated for inclusion within the National Wild and Scenic Rivers
System? No, although the Tuckasegee River is listed under study
10. Any area included within the National Wilderness Preservation System? No
11. Use toxic or environmentally hazardous substances, such as pesticides, herbicides,
rodcnticides ? No
12. Significant degradation of water quality? Short-term impacts due to accumulated
bedload sediment and TSS release during demolition and draNvdown of the reservoir
13. Significant degradation of air quality? No
14. Society as a whole? No
D-2
Duke Power FINAL Dillsboro Environmental / Biological Assessment
15. National interests? No
16. State or regional interests? Yes, enhancement and restoration of this segment of the
Tuckasegee River
17. Long term irreversible or irretrievable commitments of resources? No
is. Public health or safety hazards? No
19. Widespread controversy? No
20. Highly uncertain effects with unique or unknown risks? No
21. Establishment of a precedent for future actions with significant effects, or a decision in
principle about a future consideration? No
22. Other actions with individually insignificant but cumulatively significant impacts? No
23. Potential violation of Federal, State, or local law or requirements imposed for the
protection of the environment? No
D-3
Duke Po%%cr
FINAL Dillsboro Environmental / Biological Assessment
ATTACHIIENT E
SEDIMENT STUDY RELATING TO THE RE170VAL
OF THE DILLSBORO DAM
F-1
SEDIIIEN'r s,rUDY
Relatin- to the Removal of the Dillsboro Dam, •ruckase"ee River
Jackson C'ountr, North Carolina
FERC Project 2602
MINA 92477-01-1
March 31. 2004
Prepared for:
I)cN Hic l arbell & Associates
400 South Tryon Street, Suite 2401
Charlotte, NC 25235
Prepared by:
1%111onc & MacBroom, Inc.
307 13 Falls Street
Grecnville. SC' 29001
S64-271-959S
f' o
Introducil'011
The Dillsboro Dam was constructed in the early 1920s on the Tuckasegee River in Jackson
County, North Carolina. It includes two turbine-generating units and operates as a run-of-river
facility currently owned by Duke Power, a division of Duke Energy Colhuration. Ntilone and
NlacBroom. Inc. (NI N11.) was retained by Devine Tarbell & Associates (DTA) to study the
cortsequenccs of the removal of the Dillsboro Dam as they relate to potential downstream
sedimentation. Previous studies conducted by others have found no level of contamination of
concern in the accumulated sediments in the impoundment. However, the concern over the
extent of seduncnt mobilization has been raised. As part of this report, preliminary evaluations
were conducted to ascertain the order of magnitude of downstream transport and deposition.
Dillshoro Dam. Tuckaseuee River
The Tirckasegec River drains an area of 290 square miles at the dani. Flows are heavily
regulated by hydropower facilities upstream oil the east and west fork of the Tuckasegce [liver.
The dam impounds a linear lake 13.9 acres in sire, and 4,000 feet in length. The width of the
impoundment is typically 150 feet, roughly the same as the river up and downstream and it
closely follows and fills the pre-dam channel.
The concrete masonry dam is 12 feet high with a total length of approximately 310 feet. The
powerhouse station is located on the right abutment, while the majority of overflows pass the
dam along its mid-crest. A detailed discussion of the existing site, facilities, and management
alternatives are contained in the draft Environmental Assessment by DTA (2004).
The powerhouse: has a generating capacity of 225 kilowatts with a capacity of 234 CFS. Excess
flows go over the spillway. The spillway crest elevation is 1,922 feet above sea level.
The pool upstream of'Dillsboro Dam was inspected on March 2 and March 3, 2004, to assess
sediment deposits, identify sediment gradation, and SUrvey key cross sections. An evaluation
SF.t)IME\T STL DY ItELATING TO THE REMOVAL - PAGE: I
OF THE i111.ISBORO DAM. TLCKASEGEE RIVER
1IARC11 31. 2004
Was also conducted on representative do%vnstream sections of the rig cr from the project site Just
above Bryson City. Portions of the Impoundmcm hay. ?: low flat alluvial floodplains on one or
both sides, with surface lc,els about three feet above nonnal pool %%ater elevations. It is unclear
.vhether these floodplains are post-dam sediment deposits that na1TOv-'cd the original pool.
13at}tymetric surveys conducted in 1999 and 2001 by others show little apparent change in
sediment in the impoundment. It is likely that a state of equilibrium has been reached and little
future sedimentation should be anticipated in the impoundment. The orientation of the base
channel within the impoundment and spatial character of the accumulated sediments indicate that
the current induced by the turbine operation induces velocities adequate to scour the bed
sediment for a substantial distance upstream. The hathvntetric. data and our probes show this on
the right side of the impoundment.
I-Tvdrolo(-)'v
Sediment stability and transport are very depcndrnt Upon hoth stream flow rates (hydrologv)
flow regimes of depth and velocity (hydraulics). Hydrology data for this project has been
obtained from U.S. Geological Survey gauges 03512000, 03513000, and 03510500 and the
Dillsboro draft environmental i biological assessment prepared by DTA for Duke Power. The
xvatershed area at the Dillsboro Dann (290 square miles) is 83.6 percent of that at the gauge site
SO flow rates were adjusted by that ratio. The Dillsboro gauge has peak annual flow data 101- 55
years from 1925 to 1981, as summarized below and in the Appendix.
Key Hydrology Data
Parameter Dillsboro Dam Reach 3 Reach 4
Watershed Area, SN4 290 381 604
Mean Annual f=low, CFS 667 877 1,466
2-Yr Flood, CFS 5,827 8,210 15,582
10-Yr. Flood, CFS 10,868 16,485 31,164
sF.mNiF.N'r S"rl DY ItEL,4'I INN TO TIIF REMOVAL PAGE :
OF TIIE; D11_LSBOR0 DANI, Tt CKASEGEF. RIVER
NIARCII 31.:004
The upstream hydroelectric sites have a significant impaCt On flow rates at Dillsboro Dam and a
declining affect in the downstream direction.
Down Stream Channel
The riverbed has a hi-modal material consisting of static bedrock and cobble with an active
0ranular bed material. Three sediment samples were obtained and sieved tested to determine
their gain site distribution. Visual observation, si?:yc tests, and DTA data all confirm the active
bed material is fine to coarse sand and the D?0 size is 0.5 nun.
Significant portions of the channel have rigid bedrock boundaries overlain by a shallow veneer
of loose sand and oravel. Interspaced with the rigid boundary sections are channel segments
with threshold boundaries armored with small houldcrs and cobbles on moderate gradients, and
lower gradient alluvial segments with floodplains in the mountain valleys.
A review of the FEMA Flood Insurance Studies for Swan County (downstream) and Jackson
County (upstream of site) indicate the river has a steep overall profile with moderate to hiLl)
flood (low velocities. No detailed FEM:?L flood studies have been done in Dillsboro at the dam
site.
Reservoir Trap Efficiency
The estimated sediment trap efficiency of the Dillsboro Dam impoundment has been determined
using two separate standard engineering methods based on available reservoir data.
pool area = 13.9 acres
pool volume - » acre feet
mean flow = 667 cubic feet per second
watershed area = 290 square miles
The pool's retention time for through flow (its volume divided by its mean inflow) has been
computed and is equal to 1.0 hours. The suspended sediment trap efficiency of the pool is
SED[NIENT STUDY RELATING TO TILE REMOVAL . P,NGE 3
OF THE I)ILLSBoRo 1) OL TI 'C KASF.GEE RIVER
NIM4VII 31. 2004
related to the ratio between its volume capacity and its mean annual inflow. Based upon Mine's
curve (ASCE Manual 154), the estimated trap efficiency is near zero implying that little
sediment would be retained. This is cfue to the small capacity of the pool compared to the
volume of runoff. The percentage of suspended sediments likely to pass through the reservoir
(inverse of trap efficiency) was estimated uS111" the Churchill method (ASCE :Manual The
result forecasts that virtually all silt will pass downstream with no retention. This is consistent
with field observations and sieve tests of the sediment.
Consequently, one would not expect the Dillsboro Dam to have a significant impact on altering
the watershed's sediment yield or delivery ratio.
Sediment Denosit Types
l-leld tnspcitlons Indicate there are two t\hes of sediment deposits at the site. The first consists
of post-dam deposits of loose unconsolidated, unvegetated material (fine to coarse sand) that lies
beneath the present water body, with all estimated volume of 100,000 cubic yards. Field probes
with steel rods Cound the material is generally two to four feet thick and is underlain by firm
gravel and cobbles, probably of the pre-dam channel.
The second type of sediment deposit consists of pre\'iotns pond deposits that have accreted to an
elevation above the present pond level, forming, a low vegetated floodplain along portions of' tile
present pond's perimeter. Limited probes of this deposit su"gcst it was initially a mixture of
point bars on the inside of bends plus near bank deposits in slack water. The post-dart vegetated
hank deposits have nan-owed the impoundment to a width in equilibrium with post-dam flows
and sediment loads. Consequently, the impoundment acts more as a low gradient alluvial
channel than as a lake. The extent and volume of vegetated sediments has not been estimated.
Public remarks state that the impoundment was periodically dredged to obtain commercial
quality sand.
SEU1MENT STUD RELATING 1.0 THE REMOVAL PAGE 4
OF*mE DIL.LSRORO DA>1,TCCKASEGEE RIVER
MARCH 31.'_(}04

VisrrLd ohsCrvat?ons and review of DTA data indicate; that the Tuskasgee River has a bi-modal
bed Illaterial consisting; of static boulders and cobble plus an active bed component of 11-Ilt tall
"1';rlllll ;t' Sailel ',\ lth traces of ,ravel.
Four c(ImI)OSite sediment samples were obtained from the active bed and bank material and sieve
tests peribrmed. Samples are from the pool upstream of the dam, channel 150 feet downstream
of the dam, and channel downstream of the Route 441 bridge and pond bank.
IEVE TEST RESULTS
Downstream of Lett Bank
Gradation Upstream Pool Downstream of Dam Route 441 (North)
D I ()ti 5 ? 15 20
D84 I .ti Is 1.4 0.6
DO 0.61 8.3 0.7 0.21
1)50 0.5 3.5 0.6 0.17
U3o 0.31 0.6 0.39 0.092
D16 0.2 0.2 0.3 ---
D l 0 0.18 0.16 0.24 ---
,, I inL;
Sample ;' 1, just dowlist ream of the danl, was tine to coarse sand with fine to coarse gravel,
reflecting gravel sources in the exposed bedrock. Samples ill and #3 were virtually identical fine
to coarse sand reflecting active bed materials. Sediment sample P4 was obtained from the left
bans: and consists of firm cohesive silty loam.
SCdIiTlenl Field
The average annual sediment yield at Dilisboro Dam has been estimated in order to help
understand the si`('nificance of the volume of material deposited in the impoundment upstream of
the darn. 1-liere is limited longs-terns sediment data directly available for the Tuskasegce River,
so yield estimates have to be based on both local and regional watersheds.
SEIIINiE..\TS'U DY RE:LATINGTOTHE HEMOYAL PAGE.5
OF TnE DILLSHORO DAM. TE CKASEGEE RIVER
MARCH 11. 2004
T'll ;;!tc has a contributing watershed area reported to be 290 square miles of land in the
Appalachunl Mountain region of t\ estern North Carolina. The basin is west of the Blue Ridge
Mountain; and is tributary to the Tennessee River. It has been estimated that the impoundment
contains 100,000 cubic yards of material dominated by medium to coarse light brown sand. This
is a cowl cr\ ati\ c estimate and the actual volume is likely to be less. Sieve tests results of a
coinposit(• s.ul;plc procured during our inN,esti ,ation %vere similar to the sample results obtained
as part of'the Trash Removal Study Report prepared by DTA. Based upon an assumed density of
90 pounds per cubic loot, the impounded sediments are equal to 121,500 tons. Probes through
the sediment in selected areas found it was underlain by a mixed pre-dam river bed ofcobbles
and firm ,ray el, probably resembling similar material observed upstream and downstream of the
IIII poulldmciit.
The. U'. S. Gi:olooical Survey completed a recent study of sediment yields in three tributaries of
the Little Fenncssec River Basin itnniediately west of the Tuskasegce Basin (\VRIR03-4194,
2o03). The report contains information Oil one year of monitoring plus refers to previous
regional studies. The results of the 2000 - 2001 data are much lower than the 1970 - 1979 data
and is attributed largely to drought conditions. Figure 12 in (USGS, 2003) clearly indicates that
the ne\N data has similar to slightly lower suspended sediment yields when plotted as a function
of d schar c. Bedload sediments were found to be 25 to 44 percent of the total load. D111
hii.h llil\+ >amples in January and September 2002, 38 and 60 percent of the sediments were finer
than 0.3nim. L;sing this data, the Tuskasegec River sediment load at Dillsboro Dam is estimated
to be it minimurn of -5,419 tons per year and a maximum of 121,110 tons per year. This is based
upon the historic regional suspended sediment load range of 68 to 1 10 metric tons per square
kilomeicr plus a bedload factor. The unit sediment load was then multiplied unics the, watershed
area. Conservently, the estimated volume of stored sediment in the Impoundment IS egllal to 1.0
to 2.2 years of mean annual watershed yield.
A second source of sediment load and yield data is U.S. Geological Suivey Water Supply Paper
2364, entitled "Sediment Characteristics of North Carolina Streams, 1970-1979." This detailed
report presents a discussion of North Carolina topography, precipitation, and land use, followed
SEDINI %T S] t nl' ItFLATINGTO HIE RENIOVAI. PAGE D
OF THE DILLSBORO UA%I, I LCKASF.GFE RIVER
LIAR( 1131, 2004
by cmensIve sediment Ioad and yield field data for 152 sampling sites. Site 414S is the
Tucl:asc,_ee River at Route 23' in Dillsboro, with a drainage area of 347 square miles and a mean
daily dischar_c of 909 cfs. The estimated mean sediment yield is 100,000 tons per year, based
on 25 samples, equal to 290 tons per square mile per year. This mean annual sediment yield has
been propollionall_y applied to the Dillsboro Dam (290 square miles) leading to an estimatcd site
mcld o' S4,100 tons per year. This is equivalent to an average daily sediment load of 230 tons
per dad. The reservoirs sediment volume would be equal to 1.2 years of mean annual sediment
yield usiri?? this method. Suspended sediment concentrations increase rapidly as discharges rise
and much of the annual load is conveyed during just a few days with peak flows.
The sediment yield data in the USGS (2003) report on the Little 'T'ennessee River Basin and
earlier but longer tern USGS (1979) data for the Tuskasegee River are consistent, and from this
we forecast that the Dillsboro Darn impounds only one to two years of equivalent mean annual
sediment \ field from the watershed. Conversely, it means that the unconsolidated sediment
volume in the pool is only about two percent of the watershed's yield since the dam was made in
the 19-10's. The impounded sediment volume thus does not have long term significance oil
downstream areas because it is such a small fraction of the watershed total yield during the S04-
vcars of the clam.
Inmoundcd Sediment Resnollse
Field probes of the pool's sediment deposit indicate a bed of bedrock and/or rocky cobble along
the right bank for 1.000 t feet upstream of the dam. In the event of darn removal, no vertical
channel IIICISenlerit or headcuts are possible in this area. I lowever, the river's submerged
thal?? c: L' %? ill V, icier as this is the primary fluvial process.
The middle segment of the impoundment has a nan-ow linear fonn with two to four feet of
nlcdiuni to coarse sand over the original firm river bed, with a weak poorly defined tlialweg.
The upper end of the pool has shallow, sandy sediment with solve <gavel, blending into the
SEDI\IEV[ S'i I Dl RFLATING TO THE REMOVAL PAGE 7
OF THE D I I I.SI1ORO D:1Nr,1-I'CKASEGEE RIVER
NI:\RCI131, 2004
upstream bedrock and cobble bottom channel. Some scour of surficial sediment is expected, but
bedrock prohibits deep or upstream degradation.
The citarlnl evolution within the impounded sediment can be estimated by several different
methods depending on its fluvial characteristics and boundary conditions. Unfortunately, there
are no universal analytical techniques so one has to select the best available methodology for
each Siniatiorl. Channels are classified as having either ri-id non credible boundaries, threshold
1-MUndal-ie5 that erode only at high velocities, or mobile boundaries in alluvial channels that
readily adjust their width, depth, and slope in proportion to flow ratios and sediment loads.
Methods of stability analysis range from simple empirical hydraulic geometry equations to
threshold of movcment evaluations to advanced sediment transport studies.
The initial channel development in the Dillsboro impoundment xvd] be as an alluvial channel
with mobile bed and banks due to the recent historic depositional environment and the erodible
material. Our initial evaluation indicates flow velocities will frequently exceed stability
thresholds and general bed movement could occur. This scenario has been further evaluated for
model boundary conditions using the Copeland method (2001). The Copeland method was
developed by the Army Corps of Engineers for theoretical stability analysis of alluvial channels,
leading to a series of possible channel width. depth, and slope solutions with mobile boundaries,
and the most probable configuration. It assumed a sedinlom inflow concentration ranee of 20 to
2100 111111 and gradation based on the sieve tests. The initial results indicate that the dynamic
stability occurs (at minimum stream power) at a width of 140 to 150 feet which is similar to
cxistinu conditions but with a mild slope of only 0.4 feet per mile. 'ncc existing channel bed in
the impoundment is much steeper' than this indicating that the bed will degrade until either
equilibrium, bedrock, or the old armored bed is reached and sedinictit would be transported out
of the segment.
A second analysis was performed with the empirical Blench regime method with similar
conclusions. The channel regime equations for equilibrium alluvial channels were developed in
British Commonwealth countries based on many empirical observations and data. Consequently,
SEUIUENT STt m, RELATING TOT] I E REMOVAL PAGE. R
OF THE I111.LSIIORO nAYI, TUCK:kSEGE r RIVER
NIARCII 31.2004
we believe that impounded sediments are likely to erode with active bed transport rather than
abrupt headcuts and that underlying bedrock and cobbles will limit degradation. However, the
volume ofimpounded sediment is quite low compared to the watershed yield over the project's
life and so the downstrcam impact will ho limited.
With dam removal, we anticipate both limited vertical degradation of surGcial material and
lateral erosion of the impounded sediment up to 150 feet in width. The loose sand has no
cohesion and no coarse bed armor. Therefore, the presence of abrupt headcuts is unlikely. Sonic
slow erosion and retreat of the cohesive banks may occur, particularly on the outside of bends.
After pool levels are drawn down, there may be some batik caving or subsidence. Existing
perimeter improvements should be monitored along adjacent roads and utilities such as the
sanitary sewer in the right bank.
Downstream Channel Evaluation
The broad, shallow channel immediately downstream of the dam has exposed bedrock, small
boulders and cobbles, with tine to coarse sand in voids and sheltered areas. Farther downstream
f -0111 the Route 441 bridge to the confluence of Scott Creek is a large flowing pool merging into
a long uniform, flo%v run. A cross section inspection and sieve tests indicate a coarse sand
substrate with occasional cobble, about 75 percent covered with algae and rooted plants. Flow
VelocitieS dttrin" inspection were estimated at one to two feet per second. The steep high hanks
are stable with partial riprap coverage. This is a rigid boundary channel so it was evaluated for
sediment transport rather than for scour or enlargement.
Detailed field cross sections were surveyed spanning an approximate _500-foot reach from the
Dillsboro Dam to the confluence of Scotts Creck. The field sections were input into the U.S.
Aniiy Corps of Engineers HEC-RAS Standard Step Backwater Computer Pro-rani and several
flow events were modeled, including the mean annual flow (667 cfs); the two-year frequency
event (5,827cfs) and the 10-year frequency event (10,868 cfs) as determined from the USGS
Dillsboro ,auge. The profiles start at normal depth and use duplicate sections to aid in
SEDIMENT STUDY RELATING TO THE: REMOVAL PAGE 9
OFTiIE DiLLSBORO DAM.TUCKASEGEE RIVER
NIAM It 31.3004
convergence to nonuniform flow. The water surface profile and velocity data were then utilized
to estimate sediment transport and deposition within this critical reach. The results of the
hydraulic analysis with HEC-RAS indicate velocities of 2.65 and 2.90 feet per second for the
mean annual flow of 667 cfs and maNlmum depths of 1.22 to 1.39 feet. These values are
consistent with field observations. Velocities during higher stream flow rates increase rapidly
for the t%vo-year frequency event, due to the confined channel and lack of a floodplain.
It is noted that the velocities corresponding to mean annual discharge rates are marginal for
conveyin<, sand, and we did observe sand on the bed and in sheltered areas. General threshold
velocities would not begin until discharges are in the 1500 cfs range.
1-IEC RAS Analvsis
Vel.
Location Station (cfs Width (FT) Depth (FT) tFPS)

Downstream 5-75 667 207 1.22 2.65
of Dam 5,827 223 4.5; 5.7/6
10,868 234 6.18 7.27
Downstream 1-00 667 105 1.39 2.90
of 13ridu,e 5.527 202 4.28 6.72
10,868 212 5.98 8.56
The sediment transport rates were evaluated using the Yang method which is appropriate for
sand dominated sediments. The sediment grain size distribution is based upon the sieve test of
the reservoir material which would be moving downstream.
Sediment Transport Capacity, Tons Per Day
Station
Profile Dischai-Le. CFS 5 - 75 1 -i 00
1 667 1,951 2,260
4 2,000 9,186 9,294
5 4,000 25,040 25,010
2 5,827 43,530 43,510
6 8,000 69.300 69.460
3 10,568 105,700 108,900
SEDIMENT STVDV ItF.LATINGTO TIIE REMOVAL PAGE 10
OF TIIE D11-LSBORO D.\\I, TI'CKASEGEE RIVER
NIARC11 31, 2004
Tlie previous table indicates that the channel immediately downstream of the darn has high
sediment transport capacity that increases with discharge. The mean daily flow of 66 7 CFS can
transport 1.951 tons of sediment, which is far greater than the watershed mean daily load leaning
excess capacity to convey releases from the reservoir. The two-year frequency flood flow could
convey the reservoir's entire volume of sediment in just two days.
It is anticipated that the sediments released from the reservoir over a period of a few years could
form temporary downstream bars during low floNv, but would continue to move: downstream and
hay e little lone-terns impact.
Extended Downstream Channel
As part of their field habitat assessments, DTA established numerous transects throughout the
dog nstreanl reach. Data on substrate, cross section and coyer were collected. NIMI personnel
observed these transect locations to determine the existing sediment characteristics and to
ascertain the potential to act as short- or long-temi sediment `sinks' subsequent to the breach or
removal of the Dillsboro Dam.
Cross sectional data was utilized with the composite river slope to obtain normal depth and
velocity for a series of flows. Utilizing USES calculated flow rates from the upstream inactive
Dillsboro gauge (Station 03510500) and the downstream active Bryson City gauge (Station
03513000) flow rates were estimated by drainage area ratio. The mean channel cross section
velocities %%cre computed for uniform flow based upon the available data. The computed
velocities were then compared with the permissible velocity above which initiation of motion
and transport would be expected. The latter data, summarized below, is from the U.S. Anny
Corps of Engineers. The permissible velocities and shear stresses are those values that are
considered safe and stable for the specified bank or bed materials. Higher velocities and shear
stress values would be prone to erosion.
SFDINJEN'r ST[ DY REI_A'r1\GTO THE REMOVAL PAGE 11
OF I HE DIt LSBORO DA\I, TUCAASEGEE RINT11
MARCH 3i, 2004
PERMISSIBLE SHEAR AND VELOCITY
FOR SFI_ECTM LINING MA'TERIAI.S'ii
Permissible Permissible
Boundai-y Shear Stress Velocity
Cate,-orv Boundarv Tvne (lh-S1 1 (tt'scc?
Soils line colloidal sand 0.02 -- 0.03 1.3
Sandy loam (noncolloidal) 0.03-0.04 1.75
Alluvial silt (noncolloidal) 0.045-0-05 2
Silty loam (noncolloidal) 0.045 -- 0.03 1.75 - 2.25
Firm loam 0.075 '.?
Fine gravels 0.073 2.5
Stiff clay 0.26 3 -4.5
Alluvial silt (colloidal) 0.26 3.75
Graded loam to cobbles 0.38 3.75
Graded silts to cobbles 0.43 4
Shales and hardpan 0.67 6
Gravel;Cobble 1 in. 0.33 2.5-- 5
2 in. 0.67 3 -6
bin. 2.0 4-7.5
13 in. 4.0 5.5-12
U.S. Army Corps ol'Engineers, EMRRP-SR-29. May 2001.
Reach 43
DTA Ruch 3 is located approximately seven miles downstream of the Dillsboro Dam. Four
representative Iransects with potential for sediment deposition (runs, pools) were modeled. Usi111-1
the normal depth data and apportioned flo«s for the mean annual flood, two-year and 10-year
frequency events, sediment transport was modeled.
The results of the uniform flow analysis at four cross sections indicate that mean cross sectional
flow velocities ran-e from 3.7 feet per second for mean annual flows to 9.0 feet per second
during, the two-year frequency flood. With these ti°elocities, one can expect all fine grain and
sand size sediments to be carried through the reach without deposition, except temporarily m
pools and sheltered bank areas. During the two-year frequency flood, even gravel and small
cobbles would be in motion.
SEDIMENT STUDY RELATING TO TIIE REMOVAL PAGE 12
OF THE UILLSBORO DAM, TUCICASEGEE RIFER
MARCH 31, 2003
Reach .4
DTA Reach 4 is located approximately 16 miles downstream of the Dillsboro Dam and is
downstream of the confluence of the 0coi7o1uflC River. Four representative transacts were
modeled For the selected flows to obtain hydraulic and sediment stability data. These transacts
contain a deep pool which would intuitively be more prone to sediment accrual.
The mean cross section velocities in Reach 4 were computed for uniform flow in order to assess
sediment stability. -File results indicate that velocities ranee from a ncan of 4? to %.1 feet per
second for the mean annual flow and for the two-year flood frequency flow. As in Reach 3,
these high velocities will prevent deposition and provide high transport capacities.
Sediment RudLct
The rate at \? hich sediment is scoured form the impoundment and then either deposited
immediately downstream or transported even further downstream is hi,hly variable and
indeterminate. However, one can approximate what may happen by empirical observations and
with numeric sediment budgets.
Observations of sediment behavior have been made at the similar size 1'nion City, Platts Mills,
and Anaconda Dams that were removed in 1999. The writer estimates that one-fourth of the
impounded sediment moved downstream during the first week after dam breaching, and that a
total of 75 percent of the sediment moved in the first three months. The scour of'the rcmainin`11
25 percent of the sediment has been spread over the next four years and some may remain in
places.
Sediment rating curves for the channel downstream of Dillsboro Dam have been prepared with
the Yang method and provide useful information on the rate of movement for a specified flow.
For example, during the mean daily flow of 667 cfs the sediment transport rate is 1951 tons per
dav. The nct or available transport is 1721 tons per day after subtracting the average daily yield
of'230 tons per day. Based on the assumed first week load of 25 percent (30,375 tons), it would
SEDIMENT STUD im_kr11G TO TI IE ItEMOVAL PACT. 13
OF -rHE UILLS110110 UA.I,TUC:KASEGEE RIVER
MARCH 31.2604
take three weeks to transport it downstream. The subsequent release load over three montlhs
would be an assumed 675 tons per day and is much less than the channel's mean nut transport
load of 1721 tons per day and should not accumulate.
Actual sediment releases and transport rates will vary %vith weather conditions, disch;ar-,c rates,
revc?,etation, and manau?ement mc-ISLINs.
Sediment Mana<-crrlent
The rate at N%hich sediment is released from the Impoundment can be re?'ulated by see oral
techniques such as pre breach water draw downs, gradual pamal breaches that limit sediment
release, sediment dredging, and stabilization in place.
A partial depth drawdown and spill\vav notch will Clllickly convert the pool into a linear
controlled channel and reveal the most scour prone areas. Critical banks on the outside of
benches or near homes, utilities, or roads should be stabilized with stone or bioenginecrill-1
measures. Limited sediment removal on the left bank immediatel`' upstream of the dam would be
helpful.
Case histories
With dam removal being a developing practice, documented case histories are limited. However,
based upon the experience of Milone and MacBroom, Inc. on many dam removal projects, some
typical inferences can he made which may apply to the Dillsboro project. Post removal
monitoring has shown that loose unconsolidated sands will tend to erode Nvhen shear stress and
velocities exceed critical threshold levels. However, the overall process can take several years to
reach a new equilibrium condition and downstream impacts have been very limited. This
presented itself at several sites including the Anaconda Dam (Natigatuck River), Edwards Dam
(Kennebec River); and Blacks Dann (Conodoguinet River) with a low sediment volume to yield
ratlo.
SEDIMENT STl'DY RELATING -rO T11F REMOVAL VACE 14
or 111E UILLSHORO DAM. TUCKASEGEE RIFER
MARCH 31, 2004
Summary and Conclusions
1. "file Dillsboro Dann has a watershed area Of-290 sgllalre miles and an estimated mean annual
sedinlerlt vield of 84,100 tons per year (USGS vauue data).
The imliounchnent at Dillsboro Dam is estimated to contain I (m),(WO cubic yards of sediment,
consistink, of fine to coarse sand.
3. The reservoir has a low sediment trap efficiency due to its small size and short one-hour
(mean flow) detention period.
4. The U.S. Fish and Wildlife Service Tier i evaluation of potential sediment colltalllinants
found no si?nlificant quality concerns.
i. Assessment of the channel stability xvithin and tllru the VIII) urufillcnt indicates tilreshold
velocities % ill exceed critical levels and sediment scour is likciv.
6. An analysis of the downstream channel indicates that it has a lli`ah sediment transport
capacity and sediments released from the dam site %vIII be convcycd rapidly downstream with
little loll`-terill depositioll.
7. Critical reservoir banks near honles, utilities, and roads should be monitored and stabilized
,xith stone riprap or bioengineering techniques as needed.

SEU1\1E\1 STLDY RELATING TO THE REMOVAL - PAGE 15
OF ME. 1)11.1 SBORO, DANI.TUCKASEGEE RIVER
M.UICI1 31.2004
REFERFNCFS
Devinc. "I-arbell and Associates, 2004. "Draft Dillsboro Fnvironn,entat Biological Assessment.,
U.S. Fish K Wildlife Service, Feb. 2004. Draft Report "Sediment Contamnlants at Dtllsboro
Reservoir: A Site Assessment and Recommendations."
l'nitcd Statc5 Geological Survey, "Sediment Characteristics of North Carolina Streams, 1970-
,9." %Vater Supply Paper 2164, prepared in cooperation x%ith North Carolina 1)ep:utment
of Environment, Health, and :'natural Resources. U.S. Dept. of the; Interior, \ ashin?ton,
D. C.
United States Geological Survey, Strcam Gauge information at 035 13000 Tuckasege.e River at
Brvson City, North Carolina. (Internet http::'?taterdata.usV?s.?aovine%nwisiuv"?
Site No -= u351 3000 b:. agency-USGS.)
Federal Enicrgency 1Management .Agency, "Flood lrlsllrance Study, Jackson County, North
Carolina," May 1990.
Federal Emergency Management Agency. "Flood hasurance Study. Swain County, North
C.:rolin:a, (date).
Federal Fnlcri-ency Nlarlmgement Agency, "Flood Insurance Study. Town of Dillshoro, Notth
Carolina," 1991.
Vanoni, Vito, Editor. "Sedimentation Fmguaeerm2," Manual and Rcport on Enginecrimg Practice
No. ?4, American Society of Civil Engineers, \V'ashington, DC. 197?
Copeland. Ronald R. et at. "hydraulic Design of Stream Restoration Projects," I .S. Atzny Corps
of Engineers, Washington, DC. 2001.
U.S. Army Corns of Engineers. "Stability "Thresholds for Stream Restoration Materials," ERDC
TN-E%IRIZP-SR-29, Vicksbur_(, %,Mississippi. 1vMay 2001.

smimEN'r SI t m, RELATING TO T11F. RENIOVAI! PAGE IG
OF THE. 1)ILLS110E40 1)A\l. TUCKASEGEE RIVER
MARCEI }1.:001
APPENDIX
k"Sinf."mL
Lan4Jract Anht!efture
an.! Enwr?nmrntsl S.'itn.-r
MILONE & MACBROOM-
d 716 Sau•h Main Suect
Cheshire, ConneCtlCut 06.410
[phone] fax [phone]
Si-LET No. OF_ -
CALCUii.TFD 8YDATE
CHE::KED GY __ __ CaIE .-
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[phone] iax [phone]
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SHEET NO. ----- Of--
CALCULATED BV DATE
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npstream Channel
.__ ir.._.... ^_ orentration -..-.) 20C
.._aKe Channel
11mian Channel .._.:tn if t) 130

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123 22EG CMC 3 5.059E 5.85 ...._ ..C3 9.6-
2vo 92._ .. OO . 01571 1015 2.64 DA5 2.49 ..-.._r
366 5C6 0.3:1C34 3 .,.OJ_' 13.52 ...., .. J.U 1 .19
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150.0 11.1 0.;DQ73 01333 1,73 3._.3 3.18 0._. :_w--
1 3.'0 10A C..,..,.... 0.532;, 1.27 302 0.13 0.18 _o.w !r
1 9.8 C.NME2 C.C3:4 305 3_..9 0._: .._. ..ewer
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spec_`_-„ Gravity of S°.Rrcnts 2.0
viscot.ty __.Z)
Di_,.....___ (cfs, 5827
UPSIroam Chanel
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Roughness Value 006
3a__._,... Energy
c7i to _ 10pe n ..: we -:aM us
12.0 377.9 DION47 00120 5.95
24.0 155.6 0.00014L O) 0,57
36.0 92 A COOM23 01547 1407
48.0 64 . ... i OM94 00521 17 Al.
60,0 49A ,..,.,0354 04 t, __.,
•u•0 39.i O. 0000.. ?..,_ 15.7S
34.0 33A 0ODO0'':1 .,.N25 1531
96A 206 MOW! G.N02 17AD
,QN3 22A ME D O 3,
.O 20.. ?•'OC 6S 0.0351 1500
144._ 18 DAOGU7 5AM 1403
156.0 1M O N0005 7 CAM 1434
158.0 O.000KS ...___? 13 A3
180.0 15A 3.000 63 0..313 12.90
WE 14A 0.0000-9 :'.0337 12.36
204._ 13A 0. 0:...;7 0..._02 11.c5
216... 12.7 0. 0030-0 0. 0:9-i 11 AS
223.3 12.1 0.0:.... _ 0.093 10.9
240.0 11.6 C400:72 VON 10.50
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149.3 180 0.. BOW 0•G 35 .x.59
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Velocity iv•,_m or Stress Regime
_.._., v.01 501 ._,.,w'er
1 .36 0.0Z 1A4 ,_., __
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3 . 0 4
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206 0.9 .,. ,5 LCr1cr
2,15 0.09 0.01 Lower
225 .3. 'Q? 0 ..
225 0._0 ,.M Low_r
204 0._0 0.36 LD-"er
2.13 D._ 36 ti__r
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Median Charms! .._, _:I W! 120

Lee Ri, -
SiCe Slope
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_2A 25.5 0. _..__2 D A523 1307
210 25A ('.CGN32 0A567 13.81
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600 ,.Z A , .OM A 0 N506 13 AO
720 ---•0 0.,..,,,_40 Oa490 1336
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204.0 _...I O..,CCi- _.,2 55 _.._..
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243.0 11 0 _ A0005? x340 :..
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2.59 U.O? 0.53 Loi mr
2.32 028 007 --ow--

2..2 0.03 0.24 ?,.,. _
2.07 O.G. 3 0.21 :., ..--
2&4 ON8 C.i3 _00`
2.C2 .'B 0.15 I-c f.' -'
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l A 0.49 329 L _
1.4v 0. _0 ;.28 ;..:..__

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134 Ono 007 Lower
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M 12A 2._SO 0.2 5 6 6 1104 3 .34 O._, 035 _..,.-r

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ire+.? _.. _., .. -._.. ..-. _._.-., ...may -
15.,.0 13A .,._,='yt_ CA474 8.95 231 006 021

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-_2._ 3 0.020475 0.0461 8.15 305 026 008 Lc . _.
204.0 :.. C.,...4_ 0._0, 457 700 223 r;. 17 0.27 _. .r
zi6.0 7A7 201 A 301
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Sala Factor 0.2
nopth (it) 7.43
width (it) 220.29
slope ._..; f_1 0..,C.,_54
(,`t;z) 3.4%
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Staticn zic at_on Data
Station Elevation MatiOn Value
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40 Sediment Characteristics of North Carniina Streams, 1970-79
NORMAL DEPTH ANALYSIS
Normal De th Analysis - Tuckaseoee River I
REACH 3 Q,=3,21 Of !Q,,,=16,485
Max. Bank
Location ; Q cfs I WSEL I d ft VEl_ fqs Fr 1 TWfft Elev.
_
Transect 1 877 i 87.36 2.26 3.56 0.48 i 145 90 J
8,210 92.20 7.10 8.49 0.59 ; 150 '
16,485 - -- ---- - -- r--- ----- - ;
95.54 10.44 j 11.24 ! 0.63 - ------ .._..
150 ' _.-__ ---- ___ -
Transect 2 i 877 81.11 1 3.31 I 3.36 ',
0.47 168 86 8
8,210 -
1 85.58 7.78 1 8.01 0.58 173 '
16,485 88.67 i 10.87 10.54 0.62 I 174 `
Transect 4 877 ! 92.26 4.66 _ 3.86 1 0.49 ; 118 # 101.0
! 8.210 101.60 I 10.00 ( 8.70 j 0.59 j 140 '
16,485 13.60 11.30 0.63
105.20 I 145 '
Transect 10 877 ,
1 87.58 - 5.58 3.97 0.49 108 96.2
-- 8,210 93.30 11.30 8.80 0.59 _ 136
1 16,485 I 96.97 14.97 I 11.41 0.63 141 ' I

REACH 4 I
Qm=1,466 1 Q2=15,582 Q,0=31,164
- 1- Max. Bank
Location Q cfs WSEL ' d(ft) VEL(fps) ! Fr TW ft Elev.
Transect 5 1,466 -
91.80 _ 4.40 4.60 0.51 128 i 100 0
15,582 99.25 11.85 10.46
0.62 - _ _--
169 ' ;__-- -_ - _
j 31,164 103.82 16.42 13.76 0.66 170 '
Transect 7? 11466 90.21 2.91 3.79 0.49 I 209 ?
15,582 95.99 1 8.69 9.43 0.61 1 222 '
31,164 1 99.90 ! 12.60 12.37 ' O.fiS 222 `
Transect 8 1,466 94.61 3.81 3.79 0.49 209 :3
15,582 100.40 9.60 (
9.45 0.61 221 '

Transect 9 31,164
1,466 _...._.__.
1 104.25 13.45 1 12.46 -i 0.65 (
j 88.80 3.60 I 4.64 0.51 I 221 '
125
94.8
15,582 i 96.16 10.96 10.33 0.62 176 '
i 31,164 100.58 15.38 13.63 - 0.67 176*
` Flow beyond cross section - extended
# Divided Flow
Water i;esources
Data Catcaor u: Geaaraahic Area:
Site Information North Carolina - 9?
USGS 03510 00 TUCKASEGEE RIOTER AT DILLSBORO, NC
Available data for this site Station home page ? C0
Station Description
LOCATION
Latitude 35°22'00", Longitude 83°15'37" NAD27,
Jackson County, North Carolina, Hydrologic Unit 06010203
DRAINAGE AREA
347.00 square miles
GAGE
Datum of C, - is 1,950.15 feet above sea level NGVD29.
STATION TI PE:
Surface Water
STATION DATA:

T) pe?
Data
i3e„in Date
End Date Count
Peal: streamllow 1928-U8-15 1981-12-31 55
I)ai1- stretimflo?r -? 1933-10-01 1981-1?-31 176?1
?l_ater Ouaiity San) 'esj 1956-11-O1 1982-UI-04 69
SITE OPEILk'fION:
Site is located in North Carolina; record is maintained by North Carolina
CONTACT INFORMATION
Email questions about this station to tg-w-nc NN ISWeh Data In0L1iries@`um,s.2o%,
Questions about data ;gs-w-nc NWISWeb Data Inquiries0vus?gs.gov
Feedback on this websitcQs-w-nc NWISWeb IMaintainernus2s_2ov_
** USGS 03510.00 TUCKASEGEE RIVER AT DILLSBORO, NC
littp:/Iwaterdata.usgs.-oN•/iic/nNi-isin8visntan?
Retrieved on 2004-03-30 10:39:00 EST
Department of the L.nt?ri?r, U S. Gehl ical SlIEL(•y
_V%SGS N tsr_llesstl>rS ct1 tisirtfi Carolina
'riac? Statement 11 Disclaimer 11 accessii?ility
0.67 0.67naduwol
Top
F,x )lanation of terms
http://n«is.waterdata.us`s.,,ov/nc/iiNvis/nevisman/?site_no=03510500ka?ency_cd=USGS 3/30/200-1
USGS 0510500 TUCKASEGEE RIVER AT DILLSSORO, NC
50000

L 40000
U
30000
U
^I 20000
3
O
c..
10000
U

0
1930 1940 1950 1960 1970 1980
DnTES: 08/1511920 to 12/3111981
http://I1VJ15.\i'ater(lata.USos.?,o\,lncln"-islpeak-?sitc_no=03510>00,-a?;encv_cd=USGSB:f or... -3 )/30/2004
JUl „ u,u
water R^_sources
Data Cateoor? : Geonranhic Area:
Ca?oliiia
SIT fc3c° Water NO
,
Peak Streamflow for North Carolina
USGS 03510500 TUCK,kSEGEE RIVER AT DILLSBORO, :NC
Available data for this site Station home page GO
Output formats
Jackson County, North Carolina ; Table-
Hydrologic Unit Code 06010203 Graph
Latitude 35°22'00", Longitude 83°15'37' NADZ 7
• 1 Teb-saparated_file
Drainai e w-ea 347.00 square mules
Gabe datum 1,950.15 feet above sea level NGVI)29 I VJATSTORE formatted file
lReselect output format
Gage Stream- Gay*e Stream-
Date I'ater
Height flow Date Hci?ht flow
Year (feet) (cfs) I e`er (i'ect) (cfs)
1928 Aug. 15, 1925 Ca 11.00(} 1955 1\1ay 231 1955 7.20 1 5606
1929 h1?u. 14, 1929 10,200 1956 Apr. 16, 1956 7.55 5,1 GOf'
1930 Nov. 03, 1929 3.360
1957 Apr. U5, 1957 11.51 13,2UOt' I
1931 Apr. 22, 1931 4,900
1932 1\1ay 01, 1932 L? 1,90O 1958 Nov. 19, 1957' 7.56 5,17U?'
1 F 1933 Oct. 17, 1932 8?00 1959 Jan. 21, 1909 7.63 5,2gOf'
1931 Feb. 26, 1934 Ca 6?7Q 1960 :?pr. 04, 1960 6.30 3,41 U6
1935 IJan. U9, 1935 5.03 5,410' 119(,1 Feb. 25, 1961 8.56 6.8006
1936 Apr. 06, 1936 10.27 9,800 ] 962 Dcc. 12, 1961 9.03 7,6706
1937 Jan. 03, 1937 9.02 7,1=10 1963 ?>r. 12, 19631 F 8.82 7,2706
1938 Jul. 23, 1938 S.48 6.300 til
1964 Apr. 07, 1964 9?3 8,0606
1.939 Feb. 15, 1939 9.04 7.380 i
1940 Aug. 30,-l 940 21.96 52,600 1965 Oct. U4, 1961 1.5.61 25,30U6i
1941 Jul. 07, 1941 7.13 4 4g0; 1966 Fe b• 13, 1966 1 ].58 13,3006
1912 May 20, 19742 8.40 6 570' 1967 Nun. 04, 1967 11.79 13,8006
1913 IDec. 29, 1942 10.13 9,850' 1968 Mar. 12, 1968 7.87 5,6506
1911 Feb. 27, 1914 6.90 1,200 11969 Feb. O2, 1969 7.12 1,5106
19-15 Apr. 17, 1945 7.32 1,780, 1970 Dec. 30, 1969 6.61 3,7906
UE Jul. 19, 1971 6.06 3,1006
http://nwis.waterdata.us?s.gov/nc/mvis/peak?site_no=U3510500&agency_cd=USGS&for... 3/30/2004
23 Peak- Strean flow Qualifica ion Codes.
i -- Discharne affected to Unknown degree by RgLlladon or Diversion
6 -- Discharge affected by Regulation or Diversion
Questions about data ns-%v-ne NWISWI-b Dit-m lnqu_irie,,0)uscs.Lov
Feedback on this websitecs-w-irc NNkl]SWeb Nhint oner(ujuses_Lov,
Surface Water for North Carolina: Peak Streamtlow
httpa/?F•aterdata.uc?s.bo?inc/nti? is/}?cals',
Retrieved on 2003-03-30 10:17:07 EST
T)cT_artment cif the Interior, U.S. Get lo2ical Surrey
klSS:S AV.ttt-r Resources ui' North ?'arnlit?a
F'ri?a:v Statement. 11 Disclaimer 11 Accessibility
0.7 0.66?adw%kill
j:(-)P
Ex }anation of terms
---- ---
http://mvis.waterdata.uses.co%'/nc/ntivis/peal:'.1site_no=03 10-500&- ncy_cd=t'SGSB for... 3/30l2001
r?oou-rrecluenC%' )UMSnCS - ? ucl:a eee:: KiV';.r At U111sr.oro
r- I L _?, r<
-?- `_:
sncnce t ara Changing iso: rd
Flood-Frequency Statistics
Site IM: Station 03510500 - Tuckasegee River At .Millsboro
TliCKASEGEE RIFER AT DILISBnRO
County Jackson
River Basin: Little Tennessee
Region: Blue Ridge-Piedmont
Historical Streamflow Data
Latitude: 35°22'00"
Longitude: 83° 15' 37"
Drainage Area: 3.17 mi'
Flood Frequency Statistics
Y:1"?: 1 _!1 1
Site ID: 03510500
Period of Analysis: 1928
Number or Peaks: 13
Statistics for Regulated Pc
Log Pearson III Estimates, in Os
Q2 Q? Q10 Q2? Q?0 Q1O0 Q300 Q?00
H Egf/g:o] EE F5200 Eg EE EE E9

Weighted Estimates, in cfs
Q? (75 Q10 Q2? Q,0 QIOU Q?UO Q?00
6970 10300 ]3000 16800 20100 =23600 2700 32900
Discharges oft specified .specified recurrence interval tire represented using the notation Qt, where Q represents
discharge and t represents the recurrence interval. For example, QS, Q25, QI00, and Q500 represent
5-, 25-, 100-, and 500-year discharges, respectively.
Flood frequency estimation methodology used to obtain th:°se estimates is described in Pope ancl_others
('__)Ql) and Robbins and N pe (1996).
? Return to the Flood Frequency home page
httr)://nc.ss,ater.us?!s.eos,Icei-bin/lloodstaLS/station.pl'?station_id=03510500 3/12/2004
m (IJSGS
science for achanging warld
Flood-Frequency Statistics
Site ID: Station 03513000 - Tuckasegee River at Bryson City, Regulated
T 'CK,NSEGEE RIVER AT BRYSON Crrv
CoUMV: S%1ai11 Latitude: 35°25'40" Site ID: 03 13000
River Basin: 1.1ttle re»nessee Longitude: 83°26'51" Period of'Analysis: 1941-1995
Region: Blue Rid?c-Piedmont Drainage :area: 655 m" `umber of Peaks: 35
Current Strcarlltlim Uata
I Ilstol-ICal Strcanlllov; Data
(Mood Frequency Statistics
Statistics tier U111-C uulated PcrioJ
IF-? Log Pearson III Estimates, in cfs
Q2 QS Q10 =Q2 ] Q?0 Q1UU Q2UU QS00
1660(l =2310(? E272(O =32200
-J 3>?00 39300 12700 4 ? 200
Dischcrt,gcs of el spcCil?ed recurrence intel-1-411 care repl-esented using the notation Of, where Q repre.scnts 41isChrn??,('
(11,411 rcPresOuts IhC )'ecrurc'l7Ce irttCl-WI1. 1'01- c?sample, 05, Q25, 0100, and 0500 represent j-, 'S-, 100-, 4n'i iOO-
v"'lF' (1r.5( h(tl cs, respcclil'ch
(=lood trC(jutnc}' estimation methodology used to obtain these estimates is described in Pope and oflicr.-? (2M)l ) and
Robbins and Polk ( 1906).
Return to the Flood Frequency home page
Imp: nc.%%liter.use,s.?,ov;c-,i-bins'tloodstats-station.pl?station_id==O3?1:>000* tl3i]3'_00
vJdter Rcsour.'rs
Data Category: Geographic Area:
Surface Water . Nocth Carolina 90
Calendar Year Streamflo`Y Statistics for Forth Carolina
USGS 03513000 TUCKASEGEE RIVER A'r BRYSOV crrY, ETC
Available data for this site Surface-water. Annual streamflow statistics -] GO
Swain County, North Carolina I' Output formats
Ikdrologic Unit Code 06010203 HTML table of all data
Latitude 35°25'40", Longitude 83°26'51" NAD27 ?
Draina,c area 655.00 square miles Tab-separated data
Gage datum 1,714.54 feet above sea level NGVD29 Reselect output format
1899 2,1(11 ' 1924 1,3741 19-19 2,173 ' 197-1 2,129
190(1 1,845 1927 _872 1950 1, 718 1975 2.046
li 1901 2,306 192E 1,2- 1951 1.3931 1 1976 1,729
1.10 1,592 1927 1,425 ; 1952 1,313 119771 1,744
190 -- 1,746 1928 1,813 1953 1,225 1978 1.472
1904 94? 1929 2.1=19 1951 1,147 1979 2,246
19(1 1,395 1930 1,132 1 i? 1955 1,328 1980 - 21
i 19(16 _ 2,196 1.931 1,115 ,? 19aG 1,339 1981 1,091
19(17, 1,425 1932 1,733 l 957 1,957 1 1984 1,792
1908 1.635 l 933 1,1(_x1 1958 1,42? 1985 1,056
1909 1,0961 193.1 -1.292 1959 1,53? ", 1986 925
1910 1,39S 1935 1,316 1960 1,126 1987 1,230
1911 1,415
r, 1912 1,7SU
?L91.3 C I,5S1
191411 1,17
191 4
; 1,653
1936 1,964
1937 1,722
1938 1,461
1939 1,392
1940 1,251
j 1961 1,666 1988 951
11962 1,7 33 1989 2,318
1963 1,31 S 1990 2,044
196=1 2.004 1991 I,S 35
1965 1,520 1992 1,736
?
1916 1,7=12 1941 S95 1966 1,453 1993 1,561
1917 1,865 1942 1,492 1967 1,913 II 1991 2.290
1918 1.620 1913 1.577 1968 1,346 1997 11970
(r1919 1,561 194-1 1,405 ' 1969 1,439 11998 1,805
L
1920 1,950 I 1945 1,437 1970 1,303 1999 1,380
IF I http:. inwis.Nvatcrdata.usgs.gov; ncinwis./annual!?site_no=03513000&agency_cd=USGS
annual mean Annual mean Annual mean 'I Annual mean
1 Year 'strcamflo??•, Year streamflo??•, n.,
ii 8 streamflow, !;Year strcamflo??•,
in ft?/s _ in ft?/s in ft3ls in ft31s
98?i J ?.OSS I 1923 1,7 151 1 948 i? 11- G11973 ( - 2,036
P111
03!15,'00
0
1922 1,S70 1,3S2 j 1972 1 8-?2 2001 1,003
Questions about data dos-w ric_N\k'1S11'eb_Data_lnquiries' USLIIs.-Iov fu}?
Feedback on this «ebsitegs-wnc N%\'1S\%'eb Maintainer iusgs.Lov Explanation of terms
Surface Water data for North Carohl Calendar Year smeamnuw Statistics
thttp:iia aterdata.uses.gov!nc/n" is/annuaUcalendar_} ear°
Rorie.cd on 2004-0345 08:54:24 EST
Delmrtment of the Interior. U.5. Gcological Sur.cy
l ?(:S ?\;iIcr Itc.ource. of North Carolina
Privacy Statement ! Disclaimer ; Accessibility
http:!in«-is.%,?,aterdata.usgs.,(,,ovJnc/n«•is/annuaU?sitc_no=03513000&agcncy cd_-liSGS 0115%200.
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P R O P EP.. T Y S C I E u C E S
March 11, 2004
Mr. Paul Mills
Milone & MacBroom, Inc.
307-B Falls Street
Greenville, South Carolina 29601

Re: Laboratory Test Results
Dillsboro Dam
Milone & MacBroom Job No. 2477.01
QORE Job No. 6285, Report No. 94464
Gentlemen:
QORE, Inc. has completed laboratory testing on the four bulk soil samples received from the
referenced project. Testing was performed as requested by Mr. Paul Mills per the transmittal 1r, tter
dated March 4, 2004.
Four sieve analyses were performed in general accordance with ASTM D 422. Graphical report
forms are attached for each sample.
QORE is pleased to be of service to you on this project. If you have any questions concerning the
test results, or if we can be of further assistance, please call.
Respectfully submitted,
QORE, Inc.
Benjamin J. Kovaleski
Laboratory Supervisor
C)A
Gant M. Taylor, P.E.
Registered Engineer
BJK/Ij
Attachments: Grain Size Distribution Reports (4)
QORE Properry Sciences 281 Fair?orestWay Greenviae.South Carchra 29607 [phone] Fax [phone]

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Duke Pw%er
FINAL Dillsboro Environmental / Biolobical Assessment
ATTACHMENT
FINAL DILLSBORO SEDIMENT CONTAMINATION REPORT
G-1
Sediment Contaminants at Dillsboro Reservoir:
Report on Site Assessment and Sediment Analyses
U. S.
FISH & WILDLIFE
SERVICE
OF
U.S. Fish and Wildlife Service
Asheville, NC
Raleigh, NC
Januan• 2004 Final
Sediment Contaminants at Dillsboro Reservoir: Report on Site Assessment and Sediment
Analyses
Abstract:
Potential removal of Dillsboro Dam, located on the Tuckasegee River near Sylva (Jackson
County). North Carolina, has caused some concern for the potential mobilization of sediment-
associated contaminants accumulated behind the dam in Dillsboro Reservoir. We used the
framework of the U.S. Environmental Protection Agency / U.S. Army Corps of Engineers
technical guidance manual on disposal of dredged material in inland waters to evaluate this issue.
A tier 1 re\-iexy of existing- information indicated no major pollutant sources or contaminant
concerns upstream of the dam. The review also indicated that sediments within the reservoir
might have low potential to accumulate contaminants from a physical standpoint. being
comprised primarily of sand and gravel. Finally, it appears that watershed land uses upstream
and downstream of the reservoir are similar and that anv mobilized sediments from behind the
darn may merely subject downstream areas to the same sources of contaminants to which they
have been historically exposed. While no major concerns were noted in the review of existing
information. new data were collected to support management decisions (tier 2).
Six sediment samples from within the reservoir and four samples downstream were collected in
June 200; and analyzed for elemental contaminants. None of the sediment samples from within
the reservoir or downstream exceeded probable effects concentration screening values, indicating
no obvious concern. Over 80 percent of the sediment sample results were also less than
threshold effects screenino values. indicating they are unlikely of toxicological sionificance.
Slightly less than 20 percent of the sample results fell between the screening values and they
were further evaluated by comparing their magnitude to the geometric mean of the screening
values. Only two values (both for nickel) exceeded the geometric mean of the screening values.
The highest nickel concentration (41.5 ug/g dry weight) was from a downstream sediment
sample near Dillsboro gage, and the average of the four downstream samples (27.4 ug/g dry
weight) exceeded the average concentration of the six samples collected within the reservoir
(21.8 ug/g dry weight). Accordingly, the nickel concentrations behind the dam should not be a
concern relative to movement downstream where concentrations are slightly higher.
Our review of existing data and an on-site assessment (tier 1) and results of sediment chemistry
(lien ?) indicated no significant sediment contamination. This assessment is limited to the
toxicological properties of the sediments evaluated. It does not address the potential physical
impacts of sediment mobilization.
Preface
To assess the sediments at Dillsboro Reservoir. the U.S. Fish and Wildlife Service assisted
Duke Energy in a review of existing information oil potential pollutant sources to reservoir
sediments. The review of historic information (U.S. Fish and Wildlife Service. Sediment
Contaminunts (it Dillsboro Reseri oir: A Site Assessment and Recommend(itions) was
released in draft in June 2003. That draft formed the foundation for sediment samplitl,
analvses, and interpretation to evaluate the issue with additional site-specific data.
Followim-, collection of new data in late June 2003, a draft report on Dillsboro Reservoir
sediment chemistry was circulated for review and comment in July 2003 (U.S. Fish and
Wildlife Service, Pi-eliminarv Evaluation of Sediment Chemistry Dutu fa- Dillsboro
Resemi oir). Tile current document is the final report of the U.S. Fish and Wildlife Service
oil the sediment evaluation project; it is a compilation of material front the previous two
draft reports as well as new material gleaned from reviews of those drafts.
A Sediment Evaluation report summary was included in the Draft Dillsboro Environmental
Assessment ! Biological Assessment. Reviewers of the Draft Environmental Assessment
included the U.S. Fish and Wildlife Service, U.S. Forest Service, North Carolina Wildlife
Resources Commission, North Carolina Division of Water Resources, North Carolina
Division of Water Quality, Eastern Band of the Cherokee Indians, Jackson County Soil
and 'l'ater District, Western North Carolina Alliance, Town of Dillsboro, and Duke Power.
Steve Johnson (Duke Power) provided valuable project coordination, and Jon Knight
(Devine Tarbell R Associates. Inc.) assisted with study design and sample collection. Scott
Fletcher (Devine Tarbell & Associates, Inc.), .foil Knight, Steve Johnson. Jeff Lineberger
(Duke Power). John Wishon (Duke Power) and Sara Ward (U.S. Fish and Wildlife Scr'ice)
reviewed earlier versions of this document. Jim Dwyer (U.S. Fish and Wildlife Service)
assisted with interpretation of sediment chemistry results. Their contributions are
appreciated.
Questions, comments. and suggestions related to this report are encouraged. Inquires can
be directed to the U.S. Fish and Wildlife Service at either of the following addresses:
Tom Augspurger
U.S. Fish and Wildlife Service
P.O. Boa 33726
Raleigh, North Carolina 27636-3726
Mark Cantrell
U.S. Fish and Wildlife Service
160Lillicoa Street
Asheville, North Carolina 28801
For other information on the Dillsboro Project, please contact:
John Wishon
Nantahala Relicensing Project Manager
P.O. Boa 1006
Charlotte, North Carolina 28201-1006
iii
Contents
PAGE
ABSTRACT ii
PREFACE
LIST OF TABLES and FIGURES v
INTRODUCTION I
?-t E'II IO DS 1
RESULTS
DISCUSSION 8
REFERENCES 10
APPINDICIS
Appendix A. Chain 01'Custody for June 2003 Sediment Samples
Appendix 13. Analytical Data Report for June 2003 Sediment Samples
iv
Tables and Figures
PAGE
Fable 1. National Pollutant Discharge Elimination System (NPI)ES)
facilities upstream of the Dillsboro Dam. 1 I
Table 2. June 2003 sediment collection sites within Dillsboro Reservoir
and downstream areas. 12
Fiz:ure 1. Dillsboro Reservoir and vicinity.
Figure 2. Dillsboro Reservoir bathymctry.
13
14
Figure 3. 1967 aerial photooraph of mixing zone of Scotts Creel:
Downstream of Dillsboro Dam. 15
Figure 4. June 2003 Dillsboro Reservoir sediment sampling sites 16
Figure 5 (a-h). Elemental contaminant concentrations of sediments collected
within the Dillsboro Reservoir (D1, D2. D3, D4. D5 and D6)
and downstream of the reservoir (DG 1, DG2, I3C I and BC2). 17-20
v
Sediment Contaminants at Dillsboro Reservoir: Final Report on Site
Assessment and Sediment Analyses
Introduction
Potential removal of Dillsboro Dam, located on the Tuckasegee River near Sylva (Jackson
County), North Carolina, has caused at least some concern for the potential mobilization of
sediments accumulated behind the dam in Dillsboro Reservoir (Figure 1 and 2). Sediments can
accumulate contaminants. and at high concentrations those contaminants can be an in-place
concern as well as a concern upon sediment mobilization. To assess the sediments at Dillsboro
Reservoir, the U.S. Fish and Wildlife Service (Service) assisted Duke Energy (tile dam owner
and operator) in a review of existing information on pollutant sources potentially affecting
reservoir sediment quality at Dillsboro (tier 1). The Service also recommended additional
sediment sampling, analyses, and interpretation to evaluate the issue with current, site-specific
data (tier 2). This document is the final report of the Service on the sediment evaluation project;
it is a compilation of material from previous drafts as well as new material gleaned from reviews
of those drafts.
Methods
There are no regulations or standards that dictate the approach to be used in evaluating potential
sediment contamination at a dam removal site. However, determining the need for any
contaminant sampling, and the design of any needed sampling effort. can certainly benefit from
well-established procedures aimed at guidim, an evaluation of the potential for contaminant-
related impacts from sediments proposed for dredging. The joint U.S. Environmental Protection
Agency and U.S. Army Corps of Engineers technical guidance manual on evaluation of dredged
sediment (USEPA/USAC E 1998) was used to determine an appropriate level of effort to address
this issue.
The USEPA/USACE Inland Testing Manual employs a tiered approach to evaluation of the
potential for contaminated sediment impacts. Evaluations start with a tier 1 assessment (using
readily available existing information to assess the potential for a contaminated sediment
concern) and proceeding in a step-wise fashion through tiers 2 (surface water and sediment
chemistry), tier 3 (toxicity testing) and tier d (bioaccumulation testing) only to the extent
necessary to address the issue (i.e., all assessments start with tier 1, they may end there or
proceed to higher tiers if additional data are necessary to guide the management decision). The
Service conducted tier 1 and tier 2 assessments for the Dillsboro Reservoir project.
Tier 1 Afelhudc: Col 1filcuion ql Exisling InJurmulion
The potential for contaminants to have been introduced to the sediments behind tile Dillsboro
Dam was initially addressed by examining existing information. This information included
relevant sources of contamination, pathways of contaminant transport. the physical nature of the
sediments behind the dam. and the chemical and physical nature of the sediments downstream
that may be impacted by any mobilization of sediments from behind the dam. Potential sources
of contamination 111CIude urban and agricultural runoff, industrial and municipal wastewater
discharges, riparian fill, spills of oil or chemicals, releases from landtills or hazardous haste
sites, and mineral extraction / refinement practices. In general. absence of pollutant sources
would indicate little need for aggressive work to characterize any potential contaminants.
Likewise. any, proposed sampling should be guided by identification of a specific issue from this
review.
To complete the tier 1 assessment, we examined tiles and databases maintained by State and
federal natural resource management agencies. N'e'e also contacted individuals familiar with the
reservoir, its operations, local land-use, and water quality.
Ticrr 2 Melhocls: Sediment collection, analt-ses mrd inlerpretution
SarIzplc locations:
Management factors considered in determining the number and placement of samples included
the historical review indicating limited known contaminant concerns and the intent of the
sampling (which is to provide current analytical data to support the inference of low contaminant
burdens based on historical data). Physical factors considered include the area of potentially
affected sediments behind the dam. bathymetry, distribution of sediments, and extent of sediment
shoaling, scour, and mixing.
Samples stations were targeted to tw,o types: 1) quiescent areas, such as inside channel bends and
nearshore depositional areas adjacent to the dam where fine-grained sediments (which have the
greatest potential to accumulate contaminants) are most likely to settle; and, 2) sediment beds
typical of the impounded reach that area likely to move once the dam is removed (and which
therefore have the greatest potential to affect areas downstream).
Sample colleclion:
Sediment samples were collected June 23 and 24, 2003, by the Service and an independent
contractor for Duke Energy. Collections were made with a stainless-steel petite Ponar grab. At
each site, two to six grabs of the top 5 to 10 cm of sediment were collected and composited to
torm one sample per site. The composite of the grab samples was homogenized by stirring with
a stainless-steel spoon in a stainless-steel bucket. Debris (e.g., sticks, leaves, rocks bigger than
-1 cm') were removed during homogenization. Collection equipment was thoroughly cleaned
(ambient water rinse, detergent and water scrub, distilled / demineralized water rinse, 10'% nitric
acid rinse, and a final rinse with distilled / demineralized water) before sampling at the first site
and between sites. Three (one for metals, one For organic carbon and grain size, and one for
archival) 500-mI., aliquots of sediment were placed into series 320 I-Chem glass jars with
Teflon-lined lids. Samples were stored in a cooler on ice; (-4 degrees C) in the field and stored
frozen (< 0 degrees C) upon reaching the Service lab in Raleigh on .Lune 24`'. All samples were
collected, transported and stored under chain of custody (Appendix A).

Chemical z1nah•ses:
The 10 sediment samples were delivered to Research Triangle Institute (RTI). Research Triangle
Park, NC on June 30. 2003. Samples were wet-homogenized, freeze-dried, dry-homogenized
and digested/extracted in concentrated nitric acid using microwave lieatirt??. Elemental
contaminants ,vere analyzed by inductively coupled plasma mass spectrometry (ICP-MS).
inductively coupled plasma atomic emission spectrometry (ICP-AES) and cold vapor atomic
absorption (CVAA). 'File instrumentation consisted ofa ThernoElemental X7 ICI'-NIS, a
Perkin-Elmer 4300 Optima ICP-AES and a Leeman Labs PS200 automated mercury analyzer
(CVAA). Sediment particle sizes were determined by sieve series, and percent organic carbon
was determined by loss on ignition.
Analyses were accompanied by batch-specific quality control / quality assurance samples. An
additional aliquot of two sediments were taken to prepare duplicate and matrix spikes and
digested/extracted alongside real samples. In addition, an aliquot of National Institute of
Standards and Technology (NIST) Standard Reference Material (SRM) 2709 (River Sediment)
and a reagent blank were prepared for analysis.
RESULTS
Tier I Results: Comlfilatimi r?f Existing 11tfr»•matioat
We examined the following databases or lists of'contaminant concerns (with the source of the
data listed in parentheses):
National Priorities List (Superfund Sites)
Inactive Hazardous Waste Sites
Old Landfills
Active Solid Waste Permits
CERCLIS Sites
NPDES (surface water discharge) Permits
Sewage Sludge Land Application Sites
Registered Confined Animal Deeding Operations
(USEPA)
(NC Division of Waste Management
(NC Division of Waste Management
(NC Division of Waste Management
(USEPA)
(NC Division of Water Quality)
(USEPA)
(USEPA)
Active and abandoned solid or hazardous waste facilities are a potential source of contamination
iftlley are located in the watershed and have had a release to the environment. To address this
potential, a records search was conducted in October and November 2002. A search of State
databases and files revealed no National Priorities List (Superfund) or Inactive Iazardous Waste
Sites listed in Jackson County. Two sites were identified on the Old Landfills list, but neither of
these (the Cashiers Refuse Disposal Site and the Sylva Dump on Montieth Branch, a tributary of
Scott Creek) are in the watershed of Dillsboro Reservoir. The only active solid waste site in the
County is the Scott Creek C&D Transfer Station (1172 Mineral Springs Road in Sylva): there is
no discharge associated with this solid waste transfer facility. One CERCLIS Site was listed for
the County, the Nantahala Abandoned PCB Transformer Site (River Road, Dillsboro). An
examination of the file for this facility (11/14/02, NC Division of Waste Management, Central
Files, Raleigh) indicates the site was a pole and transformer storage yard where one PCB-

containing transformer was discovered by an employee, removed, tested, and properly- disposed-
of with State and federal agency oversight in 1999. On-site examination revealed no evidence of
leakage or other PCB-containing transformers. The Nantahala Abandoned PCB Transformer
Site received a "No Further Remedial Action Planned" status from U.S. EPA in 1999. Based on
this review, there were no chemicals of concern identified from active or inactive solid waste or
hazardous waste sites.
Surface water discharges of wastes are also a potential source of containinants. As of October
2002, there were six facilities with permitted discharges to the surface waters upstream of
Dillsboro Reservoir (Table 1). Three additional facilities are located in the vicinity of Dillsboro
Reservoir (Tuckase(_,,ce Water and Sewer Authority-Sylva Plant, Jackson Countv Board of
Education-Scott Creek School, and Ensley Adult Care). These facilities are all small (0.0063 to
0.6 million gallons per day) and, more importantly for this assessment, discharge to Blanton
Branch or Scott Creek that are hydrologically down gradient of the Dillsboro Reservoir (i.e.. any
contaminant concerns from these facilities would not impact the reservoir). Note also that Scotts
Creek School has recently been taken off line (Kevin Barnett, NCD\'VQ, pers. comm. 2003). The
Tuckasegee Water and Sewer Authority facility discharging to the Tuckasegee River upstream of,
Dillsboro Reservoir was the only major facility identified. State files indicate this facility has
been well-operated with a compliance rate of >90°!o in their aquatic toxicity nwnitoring (NC
Division of Water Quality 2000).
Other water quality information was available froin the North Carolina Division of Water
Quality's basinwide assessment report (NC Division of Water Quality 2000). Pages 30 and 31 of
that document indicate that water quality ratings (as determined by the diversity, richness and
tolerances of aquatic organisms collected in standardized sampling) for the Tuckasegee River at
Dillsboro (off SR 1378) have been good to excellent since sampling began in the mid-1980's.
Page 14 of that document indicates the Division conducted no fish tissue contaminant monitoring
in the basin between 1994 and 1999 because there were no known contaminant issues to be
addressed. Page 57 of the basinwide assessment report presents results of water quality
sampling conducted at the only Tuckasegce River station (468600000, well downstream of the
Dillsboro Reservoir): water quality was generally stood with the only exceedences of State
standards being associated with turbidity (4 of 50 samples exceeding the State standard of 25
NTUs with a maximum of 110 NTU), fecal coliforin (4 of 50 sample exceeding the standard of
200 MPN/l00m1 with a maximum of 690 MI-IN/100m1), iron (9 of 54 samples exceeding the
standard of 1000 ug/l with a maximum concentration of 7400 ug/0, and copper (1 1 of 54
samples exceeding the action level of 7 ug/l with a maximum concentration of 17 ug/1). None of
the 5-year average concentrations or 75`' percentile concentrations for these parameters exceeded
the State standards or action levels. Based on this review, there were no significant concerns
identified from surface water sources, with the possible exception of slightly elevated and
infrequent exceedence of action levels for iron and copper.
In addition to file and record reviews, telephone calls to staff familiar with water and land quality
issues in the vicinity were also made in order to identify any other potential contaminant
concerns that should be considered. The surface water quality staff of the North Carolina
Division of Water Quality's Asheville Regional Office indicated that high pl-I wastes (caustics)
historically discharged from the Jackson Paper facility should be addressed (Kevin Barnett, pers.
comm. 2002). The facility discharged paper processing wastewater to the Tuckasegee River
until the late 1980's when they implemented a water recycling protocol. Examination of aerial
photographs froin the time the mill was operational indicate the discharge was actually to Scot{s
4
Creek which enters the Tuckasegee River just downstream of the Dillsboro Dam (figure 3).
Accordingly, this facility should not have had an impact on sediment quality within the reservoir,
but it may ?\,ell have impacted downstream sediments.
Mining activities in Jackson County were characterized for their potential to impact sediments.
Staff in the Department of Gcoscicnces at Western Carolina University (Steve Yurkovich, pers.
comm. 2003) and previously collected reference material (Williams 1987) indicate mining
activities may have contributed sediments to the Tuckasegee River historically and the
formations, which attracted mining efforts, may yet produce sediments and leachates.
• Kaolin - dined in the county from 1888 to the mid-1920x, it appears that the lamest
deposits and processing plant ,vere located at Flogrock Mountain on Little Savannah
Creek with mention of processing also at Dillsboro. Those pits were filled in after the
clay was removed. Other smaller deposits were found upstream of Dillsboro Dam.
• Mica - Mined in the county until 1962, nearly 90 mines and prospects are found within
the county and the largest of these operated through W\VI and %VWII. Some 10-15 of the
largest operations lasted to the end. Both scrap and sheet mica was extracted. N-lost of
these were hillside operations that removed the soil layer to expose the ore. A few were
underground mines.
• Copper - Prospects were worked on Green's Creek, Cullowhee 1\fountain (above the
`fuckasegee Nursery at Moody Bridge), Wayehutta Creek, and Wolf Creek. The largest
and most promising was at Cullowhee Mountain. Accounts suggest that a 30 ton copper
smelter and a 10 ton lixiviation plant .vere constructed in about 1908 and it 40 ton copper
furnace installed by 1910. Large cuts. shafts and tunnels were cut. The mine was
abandoned after 1912, reopened in 1917, then closed. From 1929 to 1932 copper ore was
mined here and shipped to Ducktown for processing. Mining ended shortly after 19')--'.
Generally the ore is pyrite or cllalcopyrite (Fe and FeCu sulfides). The mines, trenches
and tunnels are still there. Thev are often filled with water that is green-bloc in color
from the copper.
• Dunite - This igneous rock, though rare, is common in Jackson County. It is composed
of the minerals olivine, pyroxene, and chromite (in small amounts). The olivine has a
density 50% greater than feldspar and quartz so is likely to settle to the stream bottom
quickly. Because of the presence of the mineral chromite, chromium concentrations
should be expected to be higher downstream from these deposits. Also, the dunites
contain some nickel that might also be in water or sediments. As dunites become
metamorphosed, minerals such as talc, serpentine, and anthophyllite are produced.
Anthophyllite in these deposits may be converted into asbestos.
• Large deposits of dunite cross the Tuckasegee just above Webster Bridge (much of
Webster is underlain by this rock), cross again near where .\site Settlement Road
intersects NC; 107, continues up Cane Creek Road and a large quarry is located at the
head of Cane Creek at Chestnut Gap. Remains of old mines can still be observed in
Cowan Valley Estates. Other locations of dunite on the upper Tuckasegce are on Caney
Fork (Judaculla Rock) and supposedly up Speedwell Road. Dr. Jerry Miller, WCU, has
5
analyzed the geochemistry of the sediments at the reservoir below the powerhouse on the
West Fork. The sediment there had an anomalously high chromium concentration.
Site-specific sediment chemistry data are very limited but inlorinative. Sampling by Duke
Power was completed on October 4, 2001. Samples were collected about 125 feet upstream of
the darn in midstream at a depth ol'a to 6 feet by repeatedly inserting a hand held corer into the
sediment. Due to corer refusal, only 5 to 6 inches of sediment was obtained during each attempt..
this material was mixed to form a single composite sample which was analyzed for metals,
volatiles, sernivolatiles, organochlorine pesticides. polychlorinated dibenzodioxins (dioxins), and
polychlorinated dibenzofurans (furans). Volatile organics. serilivolatile organics (with the
exception of a low concentration of benzoic acid). organochlonric pesticides. and dioxins / furans
were all less than the laboratory reporting limits. Sediment metal concentrations were below the
detection limits for silver, arsenic, lead and selenium. Low levels ofchrorniunl, copper and
mercury were detected. Cadmium was detected at 4.6 ug/`? dry weight, a concentration at which
effects to sensitive benthos may occur (MacDonald et al. 2000).
Beyond potential pollutant sources, review of existing data also addressed pathways between
contaminant sources and sediments of interest. and the areas potentially affected if contaminated
sediments were mobilized. These factors include things like impoundment batliynictry, flows.
watershed hydrology and land uses, sediment and soil types. and sediment deposition rates.
Many contaminants preferentially bind to organic matter and fine-grained (silt or clay)
sediments. While a darn is expected to allow fine material to settle and potentially accumulate in
shoaling areas, much of the substrate in the area of the Dillsboro dam is sandy, with little
potential for contaminant accumulation. In the State's sampling of the benthic community in
1999, the substrate at the Tuckasegee River at Dillsboro (off SR 1378) was 40 to 50 % sand and
gravel.
Important reservoir pliysical parameters were recently assessed as part of hydropower facility re-
licensing studies. Recent bathyrnetry data are available and mapped in Figure 2. The draft
"sediment issues for the Dillsboro project' summary (Duke Energy 2003) provides the follcwving
details on sediment composition, transport, and accumulation:
• The Dillsboro Project only generates electricity when there is sufficient flow in the river
and flows in excess of 284 cubic feet per second are spilled. There is negligible useable
storage for electric generation and, consequently, there is no need for dredging sediments
from the reservoir.
• Bathymetric surveys were conducted in June 2001. Sediment samples were collected
front transects established at points 1 /5th, 2/5th, 3/5th and 4/5th along the midline of the
impoundment from the danl to the headwater area. At each transect, grab samples were
taken at 4 equidistant points across the impoundment. Particle size was determined.
• The badlyinetry and particle size data show that the reservoir is similar to a river with a
sandy-silt bed. Sediment translocation within and transport through the reservoir are
dependent on the river flows. During periods of lower flows (roughly less than half
bankfull) there is sediment deposition, and during high flows (roughly bankfull or
greater) there is sediment mobilization and transport through and out of the reservoir.
6
Sediment carried b} the Tuckasegee River is highly mobile and composed of suspended
sands and silts which are deposited on the falling Hull) of the hydrograph in backwater
areas, but are easily re-suspended and moved during hi`,h flow events. Based on the
bathyrletric [slaps, the general forth of the channel bed upstream of the darn remained
unchanged. Material deposited behind tine darn is very tine grained (generally less than 1
nun) and is of such a composition that it is easily re-suspended during high flows. There
is no decrease in particle size from upstream to downstream rear the dam, which would
have indicated coarse particles aggrading due to backwater effects of the darn. Particle
sizes alone the length of the reservoir indicate that deeper areas have i nun particles, and
shallower areas have essential]}' very fine, suspcndable particles less than 0.1 nun.
During high flows, observations upstream and dcnvnstream of the darn indicated the
presence of large amounts of suspended materials: as flows dropped. this material was
not stored in the main channel except in backwaters and deep pools.
The river channel width is confined which limits lateral migration: thus, only the channel
bed can change in response to flow changes. Scouring occurs at set points in the
reservoir, such as in bends and in constricted areas. The extent of scouring changes in
relation to flow and the incoming sediment loads. Since the flow is unregulated and,
considering the present sediment accwnulation within the reservoir, there will be little net
increase of sediment storage.
Sediment in the system consists of suspended silts and sands that deposit only when
stopped by downstream controls. Sediment accumulation is not occurring at the dam face
due to the shear stress at the unit intakes. Tile elevation of the bottom of the intake
opening determines the depth of sediment accumulation at the dam, and acts as the "base
level". Tile funneling effect of water where flow enters the intake opening causes an
increase in the water velocity in the forebay area. The increased flow velocity and shear
stress causes erosion of any deposited sediment and the sediments arc transported
downstream. Headward (upstream) migration of the deposited sediments continues,
creating a channel within the sediments.
"phis channel is evident from the bathynletric data, and the depth of the channel
approximately equals the depth of tine intake. There is no delta formation (i.e., indicating
excessive sediment availability) downstream of'Dillsboro danl. There appears to be a
balance between sediment delivered to this area and the ability ofthe river to move this
material.
• Sediment particle size data indicate potential shoalin(i areas that can be targeted for
sediment analyses, particularly in the shallow areas along the shoreline.
A summation of the tier 1 review of existing information indicates that no major contaminant
concerns were identified. The cadmium concentration of the one composite sediment sample
collected in 2001 may merit additional attention. Tile periodic exceedences of the State action
level for copper in surface water may merit additional attention. The review also indicated that
the material behind the dam might have low potential to accumulate contaminants from a
physical standpoint, being comprised primarily of sand and gravel. Finally, it appears that
watershed land uses upstream and downstream of the reservoir are similar and that any mobilized
7
sediments from behind the dam may illerely subject downstream areas to the same sources of
contaminants to kvhich they have been historically exposed. %Vhile no major concerns xyere
noted in the review of existing information, it was recommended that new data be collected to
support management decisions. Those data will focus on inorganic contaminants to address the
copper and cadmium issues identified above and the mining history of the area.
Tier ? Resulls: SC(filllelll CO11CC1iO17. QualVsCs 4110 i171CI-I)rctution
'fable 2 lists sediment collection locations which arc also depicted in Figure 4. The complete
report from RTI is reprinted in Appendix li and summarized here. Laboratory blank. duplicate,
SRM and spike data were reviewed. and they demonstrate very good lab performance on this
batch of samples relative to analytical precision and accuracy.
Figure -5 (with sub-figures a-h for each clement) is a comparison of the elemental contaminant
results to freshwater sediment duality guidelines (MacDonald et al. 2000). These consensus-
based threshold effects guidelines were established to provide loNver bound concentrations below
which adverse effects to sensitive aquatic organisms should not occur (Threshold Effects
Concentrations. or TFCs) and an upper ranee of concentrations above which adverse effects to
sediment dwelling organisms may be expected (Probable Effects Concentrations, or PECs).
Eighty-one percent of all values evaluated were less than the TECs (i.e.. presumed to be
toxicologically insignificant). This category included all the data for arsenic, lead and nlcrcm-y.
Further. no samples exceeded the PECs for any elemental contaminant (i.e. no samples of
obvious concern).
To evaluate the <20 percent ofsample results that fell between the TI---Cs and PECs for cadmium
(n=1), chromium (n=3), copper (n=3), nickel (n=5) and zinc (n=3), we computed a geometric
mean of the TECs and PECs for each element and defined it as a "median effects concentration".
or NIF"C''. From Figure 5. it is apparent that only two sediment sample results for nickel
exceeded these MEC's. The two samples exceeding the NJECs Nvere collected at station D4 from
within the reservoir. and DG 1 from the Dillsboro gage area downstream of the dam (which had
the highest overall nickel concentration). None of the few samples that exceeded the TECs for
cadmium, chromium. copper and zinc exceeded the 1%tECs, and most of the results «*ere still
relatively close to the TECs for these elements.
Because none of the samples indicate a toxicolgical concern, a statistical comparison of
sediments within Dillsboro Reservoir to downstream sediments was not conducted.
Discussion
There are no federal or North Carolina sediment quality criteria or standards, but the recent
freshwater sediment quality guidelines of NacDonald ct al. (2000) arc very useful. 'File State of
Florida recently recommended these for use as ?(Yuidance in many of their programs.. including
evaluation of dredged material and risk assessment of contaminated sites (MacDonald et al.
2003). In a review by experts on sediment assessment. sediment quality guidelines like those
used here were found to offer good utility in site assessment (Wenning and Ingersoll 2002).
8
From F igure 5. it is apparent that none of the sediment samples from w ithin the reservoir or
downstream exceeded the PICs, indicating no sediment contaminant concentrations of obvious
concern. Ovcr 80 percent of the sediment sample results were also less than the TECs, indicating
they are unlikely of toxicological significance.
Slightly less than 20 percent of the sample results fell between the T C and PEC, and they were
further evaluated by comparing their magnitude to the geometric mean of the TEC and PEC for
that element. If the TEC is thought of as a threshold below which no adverse effects are
expected to occur. and the PEC is the likely effects concentration. the geometric mean of these
two is an estimate of the concentration where adverse effects may begin to be observed. This
"median effects concentration" or ` IMEC". while not a construct of the original guidelines,
appears useful as an initial screen of data in the middle category. We note also that this approach
is consistent with how the U.S. Environmental Protection Agency summarizes chronic toxicity
data in their water quality criteria program (Stephan et al. 1985). In that guidance, the geometric
mean of a No Observed Effect Concentration and Lowest Observed Effect Concentration for a
compound of interest can be used as a :Maximum Allowable Toxicant Concentration, again with
the idea that the lowest concentration of interest is somewhere between the no effect and likely
effect concentrations.
In our application of the %MECs. only two values (both for nickel) exceeded these levels. The
highest nickel concentration (41.5 ug/g dry weight) was from a downstream river sample near
Dillsboro gage. and the average of the four downstream samples (27.4 ug/g dry weight) exceeded
the average concentration of the six samples collected upstream of the dam (21.8 ug/g dry
weight). Accordingly, the nickel concentrations behind the dam should not be a concern relative
to movement downstream where concentrations are slightly higher. Although nickel was found
to be somewhat elevated relative to the screening level, nickel is a metal with little affinity for
aquatic bloaccUmulatlon, biomagnifrcation, and mobilization in sediments (Connell and Miller
1984). Nickel also has only slight to moderate aquatic toxicity (USEPA 1986), and the
concentrations observed in surface water quality monitoring of the Tuckasegce River, typically
less than a 10 u`1/1 detection limit (NCD%VQ 2000), are lower than values toxic even to very
sensitive aquatic organisms (USEPA 1986, Keller and "Lam 1991).
Concentrations of cadmium were generally low. None of our six samples upstream of the dam
approached the concentration of the moderately elevated cadmium detected in the single 2001
composite sediment sample.
This assessment included all the priority pollutant metals / metalloids. Note that this does not
address some of the elements reported by the lab, like barium, beryllium and vanadium, for
which there are few relevant comparison values. This is likely not a significant limitation
because there was no known source to the stream indicating; enrichment of these relatively rare
elements in our tier 1 assessment.
A value of one-half the method detection limit was used for the graphs in Figure 5 in the few
instances of values reported as lower than detection. This should not influence the data
interpretation because the detection limits were sensitive relative to the screening guidelines.
This assessment is limited to the toxicological properties of the sediments evaluated. It does not
address the potential physical impacts of sediment mobilization.
9
References:
Connell, D.\V.. and G. J. Miller. 1984. Clren isti-- earl Ecotoxicologi, ol'Pollution. John Wilcy and
Sons. New York. NY.
Duke Energy. 2003 (draft). Sediment Issues for the Dillsboro Project.
Keller, A.E. and S.G. Zam. 1 9 9 1 . The ac tile toxicity of selected metals to the freshwater mussel,
:Iiwdoutcr innhecillis. Euyirou To.vicol Cheer 10: 539-546.
i\,IacDonald. D. D., C.G. Ingersoll and T.A. Berger. 2000. Development and evaluation of'
consensus-based sediment quality guidelines for freshwater ecosystems..-Irch Envii•on Contemn
Toxicol 39: 20-31.
MacDonald, D.D.. C.G. Ingersoll, U.E. Smorong, R.A. Lindskoog. G. Sloane and T. Biernacki.
2003. Development and EN aluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection. Tallahassee, FL.
NC Division of Water Quality. 2000. Basinwidc Assessment Report: Little Tennessee River. Water
Quality Section, Environmental Sciences Branch. Raleiglt, NC. 83 pp.
Stephan, C.F., D.I. Mount. D.J. Hansen, J.I I. Gentile, G.A. Chapman and W.A. Brungs. 1985.
Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic
Organisms and their Uses. U.S. Environmental Protection Agency, Office of Research and
Development Washington. DC.
TVA. 2002. Results and summary of toxicity testing of sediments in Tuckasegee River and Scotts
Creek in vicinity of Dillsboro. NC.
USEPA. 1986. Ambient water quality criteria for nickel. ETA 440/5-86-004. Office of Water
Regulations and Standards, Criteria and Standards Division, Washington, DC.
USEPA/USACE. 1998. Evaluation of dredged material proposed for discharge in waters of the U.S.
-Testing Manual. EPA-823-13-98-00=1, Washington, DC.
Wennin-. R.J. and C.G. Ingersoll. 2002. Summary of SETAC Pellston Workshop on Use of
Sediment Quality Guidelines and Related Tools for the Assessment of Contaminated Sediments; 17-
22 August 2002: Fairmont, Montana, USA. Society of Environmental "I_oxicology and Chemistry
(SE"NAC). Pensacola, FL.
Williams, M.E. 1987. Histol), ol'Juckson County. The Jackson County Historical Association.
67dpp.
10
Table 1. National Pollutant Discharge Elimination System (NPDES) facilities upstream of the
Dillsboro Dam.
Facilih, Name

I i Volume
I Receiving stream
Major facilities
Tuckasegee Water and Sewer Authority i 1.5 NIGD Tuckasegee River
i Minor Facilities
i Western Carolina University %VTP i 0.0005 hIGD Tuckasegee RiVcr
Singing Water Camping Resort* 1 0.0075 NIGD Trout Creck
Trillium Links and Village' 0.02 1`1GD UT to Thorpe Lake
Jackson Co. 1301: (Blue Ridge School)* 0.01 MGD Ilurricane Creek
Nkliiteside Estates* " 0.1 NIGD Grassy Camp Creck
* note - all of these facilities are in fuckasegee lover headwaters and located upstream of either the Tuckasegee
Lake Dam and ; or Glenville Lake Dams t and 2
11 this facility was not constructed and has never been operated
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f ^~ .? cap' - C t 7 `?.?j / `/ '•? _
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16
Fleure 5 (a-h). Elemental contaminant concentrations of sediments collected within the
Dillsboro Reservoir (1) 1. D2, D3, D4, D5 and D6) and downstream of the reservoir
(DG 1. DG-1, BC I and 13C2). For each clement, results are compared to threshold effects
concentration (TEC) guidelines of MacDonald et al. (2000) -- values below which
adverse effects to sensitive aquatic organisms should not occur. and probable effects
concentrations (PECs) -- values above which adverse effects to sedinlent dwellint
oruanisms may be expected (Ni 'lacDonald et al. 2000). Some figures also have a "niedian
effects concentration" (N-IEC). the geometric mean of the TEC and PEC, for reference.
a) Arsenic Concentrations
35.0
30.0
25.0
a?
Z
3 20.0
L
15.0
t?
10.0
5.0
0.0
b) Cadmium Concentrations
ti n
I'IC ? 1.98
4.0
3 3.0 _i
i
6 2.0
TIT = 0.99 n
1n
0.0 ?. __ -- - -- - ,-- ?..-- - - ._..
D1 D2 D3 D4 D5
Reservoir samples
D6 DG1 DG2 BC1 BC2
Downstream samples
17
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
Figure 5 (cent.)
120
110
100
90
P 80
70
60
50
j 40
30
20
10
0
c) Chromium Concentrations
d) Copper Concentrations
150
140
130
120
110
T 100
3 90
i 80
a 70
ai 60
a? 50
40
30
20
10
0
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
13
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
Figure (cont.)
130
120
110
100
a' 90
3 80
70
a 60
a; 50
40
30
20
10
' 0
e) Lead Concentrations
f) Mercury Concentrations
0.25
0.20
3 0.15
i ?
0.10
an
0.05
0.00
i D1 D2 D3 D4
Reservoir samples
D5 D6
19
DG1 DG2 BC1 BC2
Downstream samples
D1 D2 D3 D4 D5 D6
Reservoir samples
Figure 5 (concluded)
55
50
45
40
35
3 30
-a 25
a' 20
a?
15
10
5
0
500
450
400
= 350
•3 300
250
200
150
100
50
0
g) Nickel Concentrations
h) Zinc Concentrations
20
D1 D2 D3 D4 D5 D6 DG1 DG2 BC1 BC2
Reservoir samples Downstream samples
Appendix A. Chain of Custody for June 2003 Sediment Samples
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21
Appendix B. Analytical Data Report for June 2003 Sediment Samples
Juh i 2003
Mr. Tom Au?,spur?,cr
U.S. Fish and Wildlitc Scrwice
Box 33 726
Raleiuh. NC 27601
Dear Mr. Augspurger
Please find the analytical report for the analysis of 10 Duke Power sediment
samples for trace elemental content. Samples were digested/extracted in concentrated in
nitric using microwave heating and analyzed using a combination of inductively coupled
plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass
spectrometry (ICP-NIS) for all metals but mercury and cold vapor atomic absorption
(CVAA) for mercury. Please call me at 919-541-6897 if you have any questions.
Sincerely
Peter M. Grouse
Program Manager - Trace Metals Analysis
RTI International
3010 Cornwallis Rd. - Building; 6
Research Triangle Park, NC 27709

TECHNICAL REPORT
Client: Duke Power
RTI Project No.: 08224.001.003
Date: 7-15-03
By
Peter N/l. Grohse.
Research Triangle Institute
Post Office Box 12194
3040 Cornwallis Road
Research Triangle Park, NC 27709
[phone]
pmt c ;rt1.or0
Submitted to:
Tom AuLSpur-yer
Box 33726
U.S. Fish and Wildlife Service
Raleigh, NC 27601
Phone [phone]
2 ;
INTRODUCTION
Ten (10) sediment samples 'Were received for analysis on June 30. 2003. All analysis for
aluminum (Al), arsenic (As), boron (B), barium (Ba). beryllium (Be), cadmium (Cd).
chromium (Cr). copper (Cu), iron (Fe). magnesium (M-), manganese (` li). molybdenulnl
Gklo), nickel (Ni), lead (Pb), selenium (Se), strontium (Sr), vanadium (V) and zinc (%n)
was performed by inductively coupled plasina mass spectrometry (ICP-y1S) and
inductively coupled plasina atomic emission spectrornetrv (ICP-AES) and inercury by
cold vapor atomic absorption (CVAA).
PREPARATION
Samples were wet-hoinogenized, treeze-dried, dry-homogenized and digested in
digested/extracted in concentrated in nitric using microwave heating.
QUALITY CONTROL
An additional aliquot of two sediments were taken to prepare duplicate and matrix spikes
and digested/extracted alongside real samples. In addition, an aliquot of NIST SRM
2709 (River Sediment) and a reagent blank were prepared for analysis.
MEASUREMEN'r
Sample and QC extracts/digests were analyzed as noted in the introduction. The
instrumentation consisted of a ThermoElemental X7 ICP-NIS, a Perkin-Elmer 4300
Optima ICP-AL S and a Leeman Labs PS200 automated mercury analyzer.
RESULTS
Moisture content is provided in Table 1. "Trace metal results are presented in Table 2 and
are expressed in pg/g on a dry weiglrt basis. Laboratory blank, duplicate, SRM and
spike data are presented in Table 3 and are also expressed in pg/g dry '.veight. Note that
the digestion actually provides a strong leach, which will only fully recover elements
such as As, Cd, possibly CtI. I Ig, possibly Ni. Ph, Se and 1n.
SAMPLE CUSTODY
Remaining samples will be stored for one year after submission of the report.
24
Table 1 - Sample Information
Sample ID Sample Matrix Recd Wt % Moisture
D1 Soil/Sediment 49.2 48.5
D2 Soil/Sediment 48.2 52.5
D3 Soil/Sediment 44.0 60.6
D4 Soil/Sediment 41.4 74.4
D5 Soil/Sediment 61.8 75.1
D6 Soil/Sediment 48.9 64.9
Barkers Creek 1 Soil/Sediment 53.8 56.6
Barkers Creek 2 Soil/Sediment 71.5 34.8
Dillsboro Ga e1 Soil/Sediment 71.2 34.1
Dillsboro Ga e2 Soil/Sediment 64.9 29.9
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D4 0.266 50 0.5 10 Al 34,537 43,303
D4 0.266 50 0.5 10 As
D4 0.266 50 0.5 10 B 82.1 453.8
D4 0.266 50 0.5 10 Ba 318 720
D4 0.266 50 0.5 10 Be <0.1 387
D4 0.266 50 0.5 10 Cd 2.7 402
D4 0.266 50 0.5 10 Cr 54.0 442
D4 0.266 50 0.5 10 Cu 54.6 461
D4 0.266 50 0.5 10 Fe 49,051 53,495
D4 0.266 50 0.5 10 Mg 9,460 13,273
D4 0.266 50 0.5 10 Mn 581 1000
D4 0.266 50 0.5 10 Mo 1.4 315
D4 0.266 50 0.5 10 Ni 35.5 1246
D4 0.266 50 0.5 10 Pb 23.5 1210
D4 0.266 50 0.5 10 Se
D4 0.266 50 0.5 10 Sr 14.7 409
D4 0.266 50 0.5 10 V 102 484
D4 0.266 50 0.5 10 Zn 173 564
D4 SPIKE 0.266 50 0.5 10 Al 43,303 8,766 4000
D4 SPIKE 0.266 50 0.5 10 As
D4 SPIKE 0.266 50 0.5 10 B 453.8 372 400
D4 SPIKE 0.266 50 0.5 10 Ba 720 402 400
D4 SPIKE 0.266 50 0.5 10 Cd 402 399 400
D4 SPIKE 0.266 50 0.5 10 Cr 442 388 4.00
D4 SPIKE 0.266 50 0.5 10 Cu 461 406 400
D3
DUPLICATE 0.269 50 0.5 10 Hg
NIST 2709 0.268 50 0.5 10 Hg
12,000-
NIST 2709 0.268 50 0.5 10 Mg 11,691 15:000
NIST 2709 0.268 50 0.5 10 Mn 518 360-538
NIST 2709 0.268 50 0.5 10 Mo 0.9
NIST 2709 0.268 50 0.5 10 Ni 74.8 65+
NIST 2709 0.268 50 0.5 10 Pb 11.7 12-18
NIST 2709 0.268 50 0.5 10 Se 1.6
NIST 2709 0.268 50 0.5 10 Sr 98.9 100-112
NIST 2709 0.268 50 0.5 10 V 43.2 35+
NIST 2709 0.268 50 0.5 10 Zn 95.8 100+
28
ATTACHMENT C
PRELIMINARY DILLSBORO DAM REMOVAL
MONITORING PLAN
13
DILLSBORO DAM REMOVAL
ENVIRONMENTAL MONITORING PROGRAM
An environmental monitoring plan (i.e., pre-removal, removal, and post-removal) will be
prepared in consultation with the resource agencies such as the NCWRC, USFWS, USES,
NCDWQ, NCDWR, NCSHPO, and ECBI before execution of the frill removal. It is anticipated
that Duke will meet with the pertinent agencies and other interested parties via a technical
conference to identify any resource and safety issues prior to the removal. This meeting would
ensure the full disclosure and discussion of relevant removal issues. Several of these agencies
(e.g., USFWS, NCDWQ, NCWRC, and EBCI) and other parties (e.g., local universities) have
expressed interest in participating and/or providing guidance in the monitoring phase of the
project.
Pre-Removal Monitoring
In association with the preparation of the subsequent license application for the Dillsboro Project,
a considerable amount of information was obtained on the environmental resources within the
project area. This information will be used in assessing the physical and biological changes
associated with the dam removal and will provide the pre-removal baseline conditions for which
the success of the project will be compared. This information can be found in the Final Dillsboro
License Application submitted to the FERC and project stakeholders on July 22, 2003. 'File
license application information pertinent to the dam removal project will be provided in a stand-
alone monitoring report submitted to the FERC, natural resource agencies, and interested
stakeholders prior to removal of the dam and powerhouse. Information from the subsequent
license application that will be used as baseline data for the removal monitoring includes the
following:
Water Quantity and Quality
¦ Description of current surface and groundwater quantity
¦ Applicable state water quality standards
¦ Historic and existing water quality including dissolved oxygen, temperature, point and
non-point sources, sediment quality and quantity, and other standard parameter measures;
¦ Historic and existing minimum and maximum stream flow release data
• Stream characteristics (e.g., dimensions, depths)
Aquatic Resources
¦ Historic and existing fishery resource data within the Project area and
upstream/downstream vicinity
¦ Historic and existing macro invertebrate resource data (including mussels) within the
Project area and upstream/downstream vicinity, except that a pre-removal mussel survey
below Dillsboro Dam will be conducted prior to beginning dam removal to verify the
known population of Appalachian clktoes
• IFIM study data
• Rare, threatened, and endangered aquatic species within and adjacent the Project area
Botanical and Wildlife Resources
¦ Existing botanical species and communities within the Project area
¦ Existing wildlife communities within the Project area
¦ Rare, threatened, and endangered terrestrial species within and adjacent the Project area
14
Cultural Resources
• Known archaeological and historical resources within the Project area
Recreational Resources
¦ Existing and projected recreational use, needs. and opportunities within, upstream, and
downstream of the Project
Land Use and Aesthetic Resources
¦ Existing land use and aesthetic resources within and adjacent the Project
Dam Removal Monitoring
During the actual dam removal and demolition period, a specific program associated with the
compliance with existing regulatory standards, as well as safety procedures will be implemented.
This monitoring program will include the following anticipated items (Note: additional details
and sampling regimes to be added upon consultation with the agencies and stakeholders):
¦ Photographic documentation, as well as GPS locations, of removal conditions at several
monitoring stations throughout the Project vicinity including but not limited to upstream
of the project reservoir, immediately upstream of the dam, immediately downstream of
the dam, downstream of the dam at the Scott Creek confluence access area, downstream
of the dam approximately one mile and two miles, downstream at Ferguson Fields (Near
the Town of Ela) which is used by the EBCI as a ceremonial site.
• Water quality sampling including turbidity and settleable solids, dissolved oxygen,
temperature, and pH will be taken at stations upstream and downstream of the dam.
Stream flows will also be documented during this period through use of flow meters. It is
anticipated that two sampling periods a day will be required for the water quality
parameters to address compliance with state standards. Thresholds, based on these
standards or other agency recommendations, will be used to guide continuation of the
removal process. For instance, if the established turbidity threshold is exceeded during
the actual removal (samples taken every half hour), demolition of the darn will cease until
normal ambient levels are attained.
¦ Sediment deposition within the established downstream stations or other areas of
importance will also be monitored and documented during this period.
• Bank erosion both immediately upstream and downstream of the dam will be monitored
during this period through visual and photographic techniques. If erosion appears to be
an issue, bank stabilization measures will be installed.
¦ Upon initiation of the dam removal and subsequent drawdown of the Project reservoir, a
representative of the EBCi tribal historic preservation office (THPO), along with other
qualified archaeologists, will monitor and document the exposure of any resources of
cultural significance and monitor heavy equipment ground disturbance. If any artifacts
are observed, the demolition of the dam will cease until the artifacts can be properly
documented and catalogued.
¦ Appalachian elktoe mussel monitoring will also be conducted during this period and the
post-removal monitoring period. Prior to removal of the dam, the population of this
federally endangered species (and any other mussel species) will be re-surveyed and
removed with the necessary agency permits and approvals from the site immediately
downstream of the dam and relocated to an upstream area of similar habitat and known
population. The monitoring plan will include documentation of the removal techniques, a
description of the future habitat (i.e., location, substrate, flows), cataloging and
documentation of individual mussel placement, and individual survivability.
¦ Approximately 500 little brown bats currently inhabit the Dillsboro Powerhouse. Prior to
powerhouse demolition, bat boxes (with designs and placement approved by the NCWRC
15
and USFNVS) will be installed in the vicinity of the powerhouse. The bat boxes will be
monitored for use through the removal and post removal periods.
A report documenting the removal monitoring results will be submitted to the pertinent
agencies upon completion of the activities.
Post Dam Removal Monitoring
During the post dam removal period (timeframe to be determined), a program to determine the
specific physical, chemical and biological changes in the project area will be conducted. It is
anticipated that the frequency of monitoring will be quarterly the first year after removal and
twice a year through the remaining monitoring program. Duke has stated in the NCST Settlement
Agreement that it will fund the post removal monitoring for the first two years of an anticipated
4-5 year program. This monitoring program will include the following anticipated items (Note:
additional details and sampling regimes to be added upon consultation with the agencies and
stakeholders):
This monitoring plan will include the following elements:
• Photographic documentation, as well as GPS locations, of post removal conditions at
several stations throughout the Project vicinity including upstream, but not limited to, the
project reservoir, immediately upstream of the dam, immediately downstream of the dam,
downstream of the dam at the Scott Creek confluence access area, downstream of the
dam approximately one mile and two miles, downstream at Ferguson Fields near the
Town of Ela.
¦ Documentation of physical stream changes through the use of channel cross-sectional
transects installed within the reach of the prior reservoir. Downstream sediment
deposition/redistribution monitoring, substrate type analysis, alterations in channel
morphology, and changes in flow velocity will also be measured along established
stations and transects.
¦ Documentation of bank and sediment stabilization and revegetation. Photographic
stations will be installed to document any erosion and/or stream headcutting in the
Project area. In areas of stabilized sediment, vegetation colonization will be documented
through the establishment of sampling plots.
• Documentation of the upstream and downstream changes in aquatic life such as fisheries
and macroinvertebrates through use of the U.S. EPA's rapid bioassessment protocols for
streams and riverine areas (Barbour et. al., 1999). An Index of Biotic Integrity (1131)
which will be compared to the baseline information already gathered for the subsequent
license application will be applied to the sampling program. Metrics associated with the
IBI include species richness (number of individual types) and composition, trophic
composition (e.g., proportion of predators), abundance (number of individuals) and
condition. EPT taxa richness (Ephemeroptera-mayflies, Plecoptera-stoneflies, and
triclioptera-caddisflies) will also be documented and can be used in association with the
NCDWQ's Benthic Macro invertebrate stream rating system or similar metrics. The
monitoring will be conducted through the use of standard sampling techniques such as
seining and electroshocking. Anticipated stations include upstream of the prior reservoir
(control), within the Project area, and several downstream of the Project area.
¦ Documentation of changes in water quality parameters such as dissolved oxygen, pH,
and temperature will be conducted through the use of standard sampling methods and
analysis (e.g., YSi DM multiprobe meter).
¦ Documentation of changes in riparian areas through use of photographic stations and
vegetation plots located throughout the prior reservoir.
¦ Documentation of any exotic plant, aquatic life, or wildlife introductions due to the dam
removal.
16
Monitoring of the relocated mussel population.
A yearly report documenting the post-removal monitoring results and improvements will
be submitted to the pertinent agencies upon completion of the activities. Quarterly or
semi-annual summary reports will be submitted to the agencies, as required. Action or
contingency plans (e.g., remediation) can then be developed, approved by the pertinent
agencies, and implemented if any problems are found during the monitoring period.
17
RELOCATION AND MONITORING PLAN
ASSOCIATED WITH THE
APPALACHIAN ELKTOE POPULATION
IN THE AREA OF DILLSBORO DAM,
TUCKASEGEE RIVER
INTRODUCTION
In association with project scoping concerning the Duke Power, Nantahala Area (DPNA)
Dillsboro Hydro Projcct and subsequent field surveys on the Tuckasegee River (Fraley 2002), the
Appalachian elktoe (.41as,niclonta raveneliana) and the wavyrayed lampmussel (Lampsilis
fasciola) were the only state or federally listed species of mussels located within the Project area
during relicensing studies. These mussels were located both above and below the Project dam
and impoundment. Details concerning the DPNA relicensing mussel surveys such as survey
locations, methodologies, and findings, as well as information on several other past surveys, can
be found in the survey report prepared by Mr. Stephen Fraley for Duke Power (Fraley 2002).
This information was presented in both the License Application for the Dillsboro Project and the
subsequent License Surrender Application for the Project.
Prior to submittal of the Dillsboro License Surrender Application, Settlement Agreements
(Agreements), which were signed in October 2003 by the majority of members' organizations of
the Tuckasegee Cooperative Stakeholder Team (TCST) and the Nantahala Cooperative
Stakeholder Team (NCST), included a Multi-Project Resource Enhancement measure of' the
potential removal of Dillsboro Dam and Powerhouse. As stated in the Agreements "...the Parties
acknowledge that Duke Power worked with the U.S. Fish and Wildlife Service (USFWS), North
Carolina Division of Water Resources (NCDWR), North Carolina Division of Water Quality
(NCDWQ), North Carolina Wildlife Resources Commission (NCWRC), the North Carolina State
Historic Preservation Office (NCSHPO) and the Eastern Band of Cherokee Indians (EBCI) and
complete(d) the necessary environmental, cultural resource, and engineering assessments
regarding the removal of Dillsboro Dam and potentially the Dillsboro Powerhouse. These
assessments evaluate(d) the potential effects of dam removal on aquatic species, determined the
extent of any cultural resources impacts, and considered the options of removing the
powerhouse."
In association with the License Surrender Application, a companion Environmental Assessment
(EA) and Biological Assessment (BA) to determine what extent the above mentioned actions may
have on the federally listed Appalachian elktoe mussel was prepared and submitted to the Federal
Energy Regulatory Commission (FERC), agencies, and interested stakeholders. This biological
assessment was prepared in accordance with legal requirements set forth under Section 7 of the
Endangered Species Act (ESA) (16 U.S.C 136 (c)), and follows the procedures established
through the USFWS's National Environmental Policy Act (NEPA) guidance and ESA guidance.
As an amendment to this EA/BA, the following relocation and monitoring plan for the Dillsboro
Appalachian elktoe mussels has been prepared as requested by the FERC in an August 31, 2004
Additional Information Request (AIR). It should be noted that the overall pre-dam removal, dam
removal, and post-dam removal monitoring program will also include items such as photographic
documentation at various stations, water quality sampling, flow measurements, sediment
deposition monitoring, bank erosion observations, a cultural resource discovery plan, bat
removal, revegetation surveys, and documentation of upstream/downstream aquatic changes as
described in the EA/BA and License Surrender Application.
18
ESA Section 7 Consultation and Permitting
The USMS and the other interested natural resource agencies decided that the most feasible
mitigative protection measure, due to the probable temporary adverse modification of the mussel
critical habitat that would occur if the dam is removed, is to relocate the local Appalachian elktoe
population located downstream of Dillsboro Dam.
The removal of the Dillsboro Dam will constitute a direct take of the Appalachian elktoe and thus
an Endangered Species Act (ESA) Biological Opinion and subsequent Incidental Takings Permit
will be required for the Project. This action will be initiated, prepared, and executed by the
USFWS-Asheville (NC) office and will be associated with the project-related impacts, handling,
removal, and relocation of the local mussel population to a currently known and suitable location
immediately upstream of the Dillsboro impoundment. This takings permit will be authorized
before any pre-removal surveys and any mussel relocation efforts are undertaken (see Figure I for
a project timeline). Specific details of the permit will be provided in the future through
discussions between the USFWS, NCWRC, NCDENR, and Duke Power.
Pre- Removal Mussel Survev and Relocation Effort
Pre-Removal Siu•vey
Based on the Fraley survey (Fraley 2002), two mussel species were found immediately
downstream from Dillsboro Dam (TuRM 31.7), including the Appalachian elktoe, which was the
most abundant species. The other species documented was the wavy-rayed lampmussel. A total
of 44 individual mussels (41 Appalachian elktoes) were collected and the overall catch per unit
effort (CPUE) was 4.9 mussels per person-hour of search time (Appalachian elktoe CPUE - 4.4).
Greatest relative abundance was at and to the left (descending) side of mid-channel, between 100
and 300 feet (30.5 and 91 meters) downstream from the Dillsboro Dam. One Appalachian elktoe
was found within 100 feet of the darn (70 feet [21 meters] from the dam face, center left quarter
of channel). This 100-foot segment immediately downstream from the darn contained relatively
poor mussel habitat, with much of the area dominated by a deep pool and bedrock substrate. The
remaining area surveyed contained relatively good mussel habitat, consisting primarily of shallow
runs with a mix of gravel, cobble, and sand substrate.
The same two species were found immediately upstream from the Dillsboro impoundment
(TuRM 32.6) approximately one mile downstream of Savannah Creek. A total of 15 mussels (14
Appalachian elktoes) were collected at the upstream site and overall CPUE was 3.75 mussels per
person-hour of search time (Appalachian elktoe CPUE= 3.5). A good distribution of size/age
classes (range= 25-76 mm total length) was represented by the Appalachian elktoe specimens
collected from both the upstream and downstream sites, indicating recent reproduction and
recruitment at both sites.
In association with the pre-removal survey, it is proposed that the known population immediately
below the darn be surveyed through depletion sampling (i.e., removal of all individuals) by laying
out grids running either 300 or 600 feet (91 or 183 meters) downstream and subdivided into 100
foot (30.5 meter) increments. The width of the river will be measured and divided into four equal
segments and delineated with anchored buoys at each 100 foot linear segment. Each 100-foot -
by-V4 river-width segment will be surveyed through snorkeling for all mussels with a total number
of mussels encountered and CPUE being recorded by all personnel searching the site(s).
19
In addition to the Dillsboro Dam population, there is a possibility that additional Appalachian
elktoe populations exist farther downsti.eam of the dam (Alderman personal communication;
Fraley personal communication; Fraley 2002; Federal Register 2002). Most of this reach was not
surveved during the 2002 relicensing survey effort and may be affected by the sediment releases
during dam removal. These lower reach areas will be surveyed through timed, random searches
with depletion sampling in potential habitat reaches, with effort concentrated in areas with the
apparent best mussel habitat. The total number of mussels encountered and catch per unit effort
(CPUE = number of mussels/hours of effort) will be recorded at each site. The specifics of these
additional survey areas will be determined in the future through discussions with the USFWS and
NCWRC.
A total of three separate depletion surveys will be conducted at each site where mussels are to be
removed during good visibility water conditions in an effort to capture and remove all the
mussels. At each site, these three surveys will be conducted several days apart due to the fact that
individual mussels may not be visible at certain times. The surveys will be conducted by
approved mussel experts who are experienced in mussel search techniques in varying substrates
and flow conditions and have acquired appropriate search images for the target taxa. Using
inexperienced personnel can lead to incomplete collections from the impact area, poor handling
of the mussels, and improper placement of the mussel in the relocation substrates (Dunn 1993;
Dunn et. al. 1999; Alderman personal communication; Fraley personal communication).
The depletion surveys will be conducted during a period when there is the least stress to the
mussels (i.e. moderate air and water temperatures from September through early November) and
will take place just a few months before the proposed initiation of the January through late March
dam removal period (Figure 1). Temperature stress induced handling has been implicated in low
relocation success (Cope and Waller 1995; Dunn et. al 1999). This autumn period also coincides
with the period when the Appalachian elktoes are becoming gravid which may be beneficial for
downstream reintroductions and recolonization.
Ifussel Relocation Effort
Concurrent with the three depletion sampling events, a mussel relocation effort will also be
conducted in association with the darn removal. The success of mussel relocation is dependent on
reducing stress during collection, adequate handling and transport, and selecting suitable habitat
(Dunn et. al. 2000; Cope et. al. 2003). According to Dunn et. al. 2000, the most important factor
for ensuring long-term survival of relocated mussels is the selection of a suitable relocation site.
The relocation site selected for this effort is the first shoal area immediately upstream of the
current Dillsboro impoundment (TuRM 32.6). This is the preferred relocation site for all the
collected mussels, according to the NCWRC and USFWS, due to the similar substrate conditions,
an existing and healthy elktoe population, recent evidence of recruitment, is at a location near the
affected collection areas, and provides a concentration of mussels immediately upstream of the
restored habitat which will act as a recolonization and natural recruitment center for the
downstream areas (Fraley personal communication; Cantrell personal coin inunication).
The site is approximately one mile downstream of the Savannah Creek and Tuckasegee River
confluence and is at Latitude 35 21.93 N and Longitude 83 14.962 W in Jackson County.
According to Fraley 2002, a total of 15 mussels (14 Appalachian elktoes) were collected at this
upstream site and overall CPUE was 3.75 mussels per person-hour of search time (Appalachian
elktoe CPUE= 3.5). A good distribution of size/age classes (range= 25-76 min total length) were
represented by the Appalachian elktoe specimens collected from this site, indicating recent
20
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reproduction and recruitment. This site consists of good elktoe habitat characterized by a mix of
gravel, cobble, and sand substrate. This site is also within the designated Critical Habitat for the
Appalachian elktoe (Federal Register 2002).
A one-pass survey of this population and the associated habitat will be conducted prior to the
relocation effort to establish baseline conditions and available relocation habitat. Resident
mussels found during this survey will be appropriately tagged. The relocation site boundaries
will be delineated and recorded through use of a global positioning system (GPS) and permanent
landmarks.
The mussels will be removed from the downstream affected sites (e.g., Dillsboro Dam) and
transported to the above mentioned area. Stress to the transported mussels will be minimized by
using experienced personnel, avoiding extreme temperatures, and various protection and
transportation techniques. The mussels will be moved directly to the relocation site wrapped in
moist burlap bags and placed within a large plastic cooler. The mussels will be kept as close as
possible to the ambient stream temperatures. If warm ambient temperatures are present during
the transport period, plastic ice packs will be placed in a portion of the cooler but will be well
insulated from direct contact with the mussels. Upon arrival at the relocation site, the mussels
will be measured (total length to nearest nun), weighed (total weight to nearest gram), and
uniquely marked by attaching a plastic tag (super glued) to the periostracum of each valve (Dunn
et. al. 2000; Alderman personal communication). The individual mussels will then be
immediately inserted into the substrate. It is estimated that the aerial exposure of the transported
and measured mussels will be no more than 40 minutes which according to the existing literature
is a period that did not increase mortality and/or hinder growth (Waller et. al. 1995; Dunn et. al.
2000).
The individual mussels will be placed into experimental design grids (or some modification based
on the USFWS's final biological opinion) within the relocation site and these grids will be
divided into i meter-' quadrats to facilitate the monitoring effort (Brower and Zar 1979; Du1111 et.
al. 2000; Anderson 2000; Young et. al. 2000; Cope et. al. 2003; Cantrell personal
conununication). Locations of the grid and quadrats, as well as both the initial locations of' the
relocated mussels and the resident mussels, will be recorded via use of the GPS and written field
documentation (i.e., field forms). The mussels will be distributed within the relocation site in a
manner to avoid crowding of both the resident and relocated populations.
Post Dam Removal Monitoring
A quantitative assessment of mussel survival and other conditions such as substrate and flow
characteristics will be made annually following the relocations. As a follow-up, a biologist will
investigate the grid area one month following relocation to check on the status of the mussels.
DPNA has stated in the associated Settlement Agreements that they will fund the entire post dam
removal monitoring (including the mussel effort) for the first two years of the anticipated 4-5 year
monitoring program. Thereafter, DPNA will enter into a monitoring partnership with the
agencies and other interested parties.
At each annual monitoring effort, the unmarked resident mussels and marked relocated mussels
will be observed, measured, and placed back in the quadrat from which they were removed.
Mortality of marked mussels Nvill be calculated as (marked shells recovered/(marked live mussels
+ marked shells recovered)) x 100 (Dunn et. al. 2000). Mortality of the unmarked resident
mussels will be estimated as (dead shells/(dead shells and live mussels) x 100 (Dunn et. al. 2000).
Version 1.0
January, 1999
The same process will be followed to determine mortality of marked resident mussels. Growth
will be calculated as the mean increase in length. Percentage of mussel recovery will be
calculated from the number of marked mussels (dead and alive) found in each grid cell as
compared to the number placed in the grid cell. Movement of the marked and unmarked mussels
can also be documented through use of the grid/quadrat design.
Success of the relocation will be based on the recruitment of juveniles into the local population,
annual mussel survival based on the recapture rates, establishment of improved lotic habitat
within the area once occupied by the Dillsboro impoundment, and the expansion of the upriver
local mussel population into the newly established lotic habitat. Additional success criteria may
be provided by the USFWS in association with the Biological Opinion and Incidental Takings
Permit.
Cost of Survey, Relocation, and Nfonitorimt
Due to the fact that the extent of the downstream mussel surveys cannot be determined at this
time and thus the subsequent total number of mussels to be relocated is unknown, an accurate
cost estimate for the effort (e.g., number of required man-hours) cannot be determined. An
accurate cost estimate will be provided upon the receipt of the necessary information.
Version 1.0
January, 1999
VENDOR NUMBER DATE DUKE ENERGY CORPORATION CHECK NUMBER
00000009024183 03/03/05 823775
P.O.BOX 1015, CHARLOTTE, N.C. 28201
----------------------------------------------------------------------------------------------------------------------------------------------------------•
INV NO/ VOUCHER CHANGE GROSS
REF NO REF NO DATE PO NUMBER LINE# QTY UNIT PRICE CHG CD AMT AMT DISCOUNT AMT NET AMT
------------------------------------------------------------------------------------------------------------------------------------------------------------
030205DPG-LM3 05000458 03/02/05 0 0 .00 .00 475.00 .00 475.00
DILLSBORO SURRENDER 401 APPLICATION FEE