20230177 Ver 1_ePCN Application_20230130

DWR
Division of Water Resources
Initial Review
Pre -Construction Notification (PCN) Form
For Nationwide Permits and Regional General Permits
(along with corresponding Water Quality Certifications)
April 13, 2022 Ver 4.3
Has this project met the requirements for acceptance in to the review process?*
Yes
No
Is this project a public transportation project?*
Yes No
Change only if needed.
Pre -Filing Meeting Date Request was submitted on:
6/1/2022
BIMS # Assigned* Version#*
20230177 1
Is a payment required for this project?*
No payment required
Fee received
Fee needed - send electronic notification
What amout is owed?*
$240.00
$570.00
Reviewing Office* Select Project Reviewer*
Fayetteville Regional Office - [phone] Chad Turlington:eads\ccturlington
Information for Initial Review
la. Name of project:
High Falls Dam Removal Project (NFWF Project #59195)
la. Who is the Primary Contact?*
Sean Clark
1 b. Primary Contact Email:* lc. Primary Contact Phone:*
[e-mail] [phone]
Date Submitted
1/30/2023
Nearest Body of Water
Deep River
Basin
Cape Fear
Water Classification
C;HQW
Site Coordinates
Latitude: Longitude:
35.478 -79.524
A. Processing Information
County (or Counties) where the project is located:
Moore
Is this a NCDMS Project
Yes No
Is this project a public transportation project? *
Yes No

la. Type(s) of approval sought from the Corps:
Section 404 Permit (wetlands, streams and waters, Clean Water Act)
Section 10 Permit (navigable waters, tidal waters, Rivers and Harbors Act)
Has this PCN previously been submitted?*
Yes
No
1 b. What type(s) of permit(s) do you wish to seek authorization?
Nationwide Permit (NWP)
Regional General Permit (RGP)
Standard (IP)
lc. Has the NWP or GP number been verified by the Corps?
Yes No
Nationwide Permit (NWP) Number: 53 - Removal of Low -Head Dams
NWP Numbers (for multiple NWPS):
ld. Type(s) of approval sought from the DWR:
401 Water Quality Certification - Regular
Non-404 Jurisdictional General Permit
Individual 401 Water Quality Certification
le. Is this notification solely for the record because written approval is not required?
For the record only for DWR 401 Certification:
For the record only for Corps Permit:
1f. Is this an after -the -fact permit application?*
Yes No
lg. Is payment into a mitigation bank or in -lieu fee program proposed for mitigation of impacts?
Yes No
lg. Is payment into a mitigation bank or in -lieu fee program proposed for mitigation of impacts?
Yes No
1 h. Is the project located in any of NC's twenty coastal counties?
Yes No
1j. Is the project located in a designated trout watershed?
Yes No
B. Applicant Information
ld. Who is applying for the permit?
Owner Applicant (other than owner)
le. Is there an Agent/Consultant for this project?*
Yes No
2. Owner Information
2a. Name(s) on recorded deed:
UP Property 2, LLC
2b. Deed book and page no.:
DB4943/PG40-44
2c. Contact Person:
Jeffery A Fisher
2d. Address
Street Address
PO Box 52351
Address Line 2
City
Durham
Postal /Zip Code
27717
401 Water Quality Certification - Express
Riparian Buffer Authorization
State / Province / Region
NC
Country
USA
Yes No
Yes No

2e. Telephone Number: 2f. Fax Number:
[phone]
2g. Email Address: *
[e-mail]
4. Agent/Consultant (if applicable)
4a. Name:
Nicole Thomson
4b. Business Name:
Sage Ecological Services, Inc.
4c. Address
Street Address
3707 Swift Drive
Address Line 2
City
Raleigh
Postal / Zip Code
27606
4d. Telephone Number:
[phone]
4f. Email Address: *
[e-mail]
C. Project Information and Prior Project History
State / Province / Region
NC
Country
USA
4e. Fax Number:
1. Project Information
1b. Subdivision name:
(if appropriate)
lc. Nearest municipality / town:
Robbins
2. Project Identification
2a. Property Identification Number:
00005589, 00001592, 20180164
2c. Project Address
Street Address
1460 NC Highway 22
Address Line 2
City
High Falls
Postal / Zip Code
27259
3. Surface Waters
3a. Name of the nearest body of water to proposed project: *
Deep River
3b. Water Resources Classification of nearest receiving water: *
C;HQW
3c. What river basin(s) is your project located in?*
Cape Fear
3d. Please provide the 12-digit HUC in which the project is located.
030300030407
4. Project Description and History
2b. Property size:
19.898
State / Province / Region
NC
Country
USA

4a. Describe the existing conditions on the site and the general land use in the vicinity of the project at the time of this application: *
The High Falls project site (Site) includes three parcels totaling approximately 19.9 acres located west of Highway 22 on the north side of the Deep River in High Falls, Moore County,
North Carolina. The street address is 1460 NC Highway 22, High Falls, NC 27259. The Site contains a hydroelectric power station, wooded land, and grassy areas. The surrounding
properties are residential and industrial. To the north there is wooded land and a vacant textile mill, to the east there is wooded land, to the south and west is wooded land and the Deep
River. Within the watershed of the Site, there is 47% forest cover, 24% crop cover, and 5% impervious surface cover. Elevations at the Site range between approximately 280-320 feet
above mean sea level.
The Site is within the Piedmont Physiographic region and the Carolina Slate Belt containing Metamorphic Rock, typical of northern Moore County, North Carolina. The Site is within
Hydrologic Basin (HUC) 0303003 of the Deep River Basin, which is part of the Cape Fear River drainage basin. Baseline river flows are lower in the summer (June — October) and higher
in the winter (January — April). The Deep River, with a drainage basin of approximately 1,442 square miles, originates from its headwaters near High Point in Guilford County and runs
southeast through Randolph and Moore Counties before it joins with the Haw River in Chatham County to eventually form the Cape Fear River. The Cape Fear River flows southeast until
it reaches the Atlantic Ocean in New Hanover County.
The High Falls Dam is a low head, run of river dam constructed of river rock and mortar and has a varying height between 8-15 feet. The total dam width is approximately 800 feet, with the
main overflow section being 300 feet. A reservoir of approximately 20 acres is impounded by the dam. The dam and reservoir are responsible for the loss of 19,669 linear feet of stream
ecosystem- 16,502 linear ft of Deep River and 3,167 linear feet of perennial tributaries. Removal of the High Falls Dam will reconnect approximately 19 miles of the Deep River to the next
dam upstream in Coleridge, NC.
In 1904, Thomas Woody established the High Falls Manufacturing Company, which included a spinning mill, cotton mill, and gristmill. Based on aerial imagery, a hydroelectric facility
existed on the property between 1950 and no later than 1966. In 1981, the facility as it exists now was built and includes the three turbine and generator system in the powerhouse. The
facility was owned and operated by Hydrodyne Industries, LLC. In 2018, Unique Places, LLC purchased the property and dam and continued to run the facility until September of that year
when Hurricane Florence flooded the Site and filled the turbines and power generator with mud and debris, rendering the facility unusable.
4b. Have Corps permits or DWR certifications been obtained for this project (including all prior phases) in the past?*
Yes • No Unknown
4f. List the total estimated acreage of all existing wetlands on the property:
0.27
4g. List the total estimated linear feet of all existing streams on the property:
979
4h. Explain the purpose of the proposed project: *
The purpose of the project is to remove High Falls Dam. High Falls Dam and the impounded reservoir behind the dam inhibit natural river flow and prevent natural river conditions of
shallow water and rocky outcrops from being available for aquatic species. Currently, the dam is a barrier to aquatic organisms that limits access to habitat and isolates populations. The
reservoir behind the dam is a man-made lentic system that does not provide the natural habitat associated with the Deep River.
When High Falls Dam is removed, the system will transition from a lentic ecosystem to a lotic ecosystem at and upstream of the Site. This transition will have a permanent positive impact
on the Site by increasing the area of shallow water with rock outcrops, natural riffle features, pools, runs, and woody debris. These habitats are vital for aquatic species, particularly the
federally endangered Cape Fear Shiner. The shallower water will also make temperature and dissolved oxygen more consistent with conditions preferred by Cape Fear Shiner. Once the
dam is removed, an estimated 19,669 linear feet of stream ecosystem will be regained. Restoration of riparian buffers and streambanks will also provide additional habitat for refuge,
critical for the survival of young aquatic species. The combination of these benefits will be a direct gain for threatened and endangered aquatic species of the Deep River.
The Site currently provides excellent mussel habitat, particularly from the downstream base of the dam to 150 m downstream of the NC 22 Bridge. State -listed mussels and species of
greatest conservation need have been observed at the Site within the last five years and are currently benefiting from added system stability, increased food supply, and concentrated host
fish and mussels of the same species that create a positive reproductive feedback loop. It is likely that these species will have access to additional habitat once the impoundment is
drained and resembles the typical river channel with rock outcrops and natural riffle -run -pool features. However, dam removal will disrupt habitat and negatively impact some species
downstream.

4i. Describe the overall project in detail, including indirect impacts and the type of equipment to be used: *
The recommended dam removal approach is a single-phase dam removal meaning that once a stable working pad/surface is established, the dam will be demolished all the way down to
the natural grade from one streambank to the other. A single-phase removal accounts for Site -specific conditions including the high sediment transport capacity of the Deep River at the
Site. Removing the dam down to the natural grade in 5-foot widths is expected to result in the most efficient movement of the sediment through the Site that is currently behind the dam.
The dam removal will be timed to occur in fall or early winter. Timing the dam removal for fall or early winter will mean that river flows will be lower during dam deconstruction, then
increase after removal which will help move sediment through the Site quickly and minimize potential sedimentation of aquatic organisms (e.g., mussels). A fall or early winter removal will
also avoid spawning seasons for most aquatic species.
At the discretion of the Engineer, Landowner, and Contractor, flow may be diverted through the powerhouse gates. Diverting flow through the powerhouse gates would be done so that the
top of the dam could be demolished down to the impounded water level and removed such that the rubble would create a stable working pad for the demolition equipment. Depending on
river stage at the time of removal, diverting flow through the powerhouse gates would also support a more controlled lowering of the water level to an approximate elevation of 283 feet in
the impounded reservoir, if desired.
Targeted streambank planting and additional riparian planting is included in the removal plans. This revegetation effort is focused on areas that will be exposed and will also stabilize
trapped sediment that is not in the main spillway.
Sediment and river flow characteristics are an important consideration at the Site due to the high concentration of state -listed mussel species downstream of the dam and the potential for
sedimentation of mussel habitat. A Sediment Capacity and Fate Modeling Study performed for the Site established the following assumptions:
-The amount of sediment trapped behind the dam is small compared to the flow and sediment transport capacity of the Deep River.
-Approximately 37,000 tons of material is trapped behind High Falls Dam throughout the 20-acre reservoir, which is a relatively small amount given the dam is over 100 years old.
-Approximately 8,000 tons of material is located away from the main spillway and may be stabilized with vegetation following the sediment and erosion control permit plans.
-Sediment depth averages less than 1 foot over the 20-acre reservoir. There is a relatively small "sediment wedge" behind the dam; the top of the sediment is approximately 10 feet below
the top of the dam (height of dam is 8-15 feet).
-The predicted sediment transport capacity of the Deep River is approximately 70,000 tons/year. Sediment trapped behind the dam is expected to move quickly (within about three months)
and be flushed downstream.
-River bed changes downstream will be minor.
-Channel margins where vegetation currently exists are likely to trap sediments temporarily.
-Side channels on river left are expected to become potential depositional areas.
-Sediment sampling determined that the sediment is predominantly gravel and sand sized particles overlying bedrock. Very little fine grained (silt and clay) sized particles were observed.
Prior to the work described in this permit, the Applicant will coordinate with the North Carolina Wildlife Resources Commission to reduce impacts to mussels at and downstream of the Site.
The river channel and margins downstream of the dam to 150 m downstream of the NC 22 Bridge will be surveyed for state -listed and species of greatest conservation need mussel
species. Based on guidance from the North Carolina Wildlife Resources Commission, it is expected that some of these individuals will be collected, tagged, and transported to a facility to
propagate or translocated to another site with suitable habitat.
5. Jurisdictional Determinations
5a. Have the wetlands or streams been delineated on the property or proposed impact areas?*
Yes
Comments:
No Unknown
The USACE (Ross Sullivan) met with Sean Clark (Sage Ecological) on the subject Site in August
2018 to review the surface waters as depicted in the Wetland Sketch Maps. No PJD was issued,
however, the USAGE verbally confirmed the locations of surface waters as depicted.
5b. If the Corps made a jurisdictional determination, what type of determination was made?*
Preliminary Approved Not Verified Unknown N/A
Corps AID Number:
5c. If 5a is yes, who delineated the jurisdictional areas?
Name (if known):
Agency/Consultant Company:
Other:
6. Future Project Plans
6a. Is this a phased project?*
Sean Clark, PWS
Sage Ecological Services, Inc.
Yes No
Are any other NWP(s), regional general permit(s), or individual permits(s) used, or intended to be used, to authorize any part of the proposed project or related activity?
D. Proposed Impacts Inventory
1. Impacts Summary
la. Where are the impacts associated with your project? (check all that apply):
Wetlands Streams -tributaries
Open Waters Pond Construction
Buffers
3. Stream Impacts

3a. Reason for impact (?)
3b.Impact type*
3c. Type of impact*
3d. S. name*
3e. Stream Type*
(?)
3f. Type of
Jurisdiction*
3g. S. width
3h. Impact
length*
SI
Dam Removal
Temporary
Dewatering
Deep River
Perennial
Both
270
Average (feet)
43
(linear feet)
S2
Temporary Construction
Access
Temporary
Excavation
Deep River
Perennial
Both
400
Average (feet)
20
(linear feet)
3i. Total jurisdictional ditch impact in square feet:
0
3i. Total permanent stream impacts:
0
3i. Total stream and ditch impacts:
63
3i. Total temporary stream impacts:
63
3j. Comments:
The proposed impacts are temporary in nature to remove the low head dam and will be for the minimum amount of time required.
4. Open Water Impacts
4a. Site #
4a1. Impact Reason
4b. Impact type
4c. Name of waterbody
4d. Activity type
4e. Waterbodytype
4f. Impact area
Cl (Mill Race
Canal)
Temporary Construction
Crossing
T
Mill Race Canal
Dewatering
Other
0.01
4g. Total temporary open water Impacts:
0.01
4g. Total open water impacts:
0.01
4h. Comments:
4g. Total permanent open water impacts:
0.00
There are existing bridges over the Mill Race Canal, however, they may not be feasible for use with construction equipment; therefore, a temporary
crossing is proposed but will be installed ONLY if required because the existing bridges are deemed unsafe for use.
E. Impact Justification and Mitigation
1. Avoidance and Minimization
la. Specifically describe measures taken to avoid or minimize the proposed impacts in designing the project:
The purpose of the proposed project is to remove existing impacts to the Deep River by recreating natural lotic/river conditions at the Site as well as
restoring riparian habitat. The proposed impacts are temporary in nature and will only be for the minimum amount of time required to remove the dam
and restabilize the banks. A riparian planting plan is also included in the permit drawings.
lb. Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques:
An NCDEQ approved sediment and erosion control plan will be implemented throughout the duration of the dam removal project. After equilibrium is
reached, seed and straw with seed mixes will be applied to bare areas, and areas within the floodplain will have livestakes and bare root trees installed
according to the restoration plan included in the engineering plans attached. The removal of the dam will be scheduled to avoid spawning of the Notropis
mekistocholas (Cape Fear Shiner) (May -July).
2. Compensatory Mitigation for Impacts to Waters of the U.S. or Waters of the State
2a. Does the project require Compensatory Mitigation for impacts to Waters of the U.S. or Waters of the State?
Yes No
2b. If this project DOES NOT require Compensatory Mitigation, explain why:
The impacts are temporary in nature and are designed to improve downstream water quality, restore the natural flow regime to the Deep River and restore Cape Fear Shiner habitat &
reconnect populations.
F. Stormwater Management and Diffuse Flow Plan (required by DWR)
1. Diffuse Flow Plan
la. Does the project include or is it adjacent to protected riparian buffers identified within one of the NC Riparian Buffer Protection Rules?
Yes No
If no, explain why:
There are no state regulated riparian buffers on the Deep River.
2. Stormwater Management Plan
2a. Is this a NCDOT project subject to compliance with NCDOT's Individual NPDES permit NCS000250? *
Yes No

2b. Does this project meet the requirements for low density projects as defined in 15A NCAC 02H .1003(2)?
Yes No
Comments:
The proposed project is to remove a low head dam and is not introducing any new impervious surface or concentrated areas of development within the project limits. Therefore,
stormwater management is not required.
G. Supplementary Information
1. Environmental Documentation
la. Does the project involve an expenditure of public (federal/state/local) funds or the use of public (federal/state) land? *
Yes No
2. Violations (DWR Requirement)
2a. Is the site in violation of DWR Water Quality Certification Rules (15A NCAC 2H .0500), Isolated Wetland Rules (15A NCAC 2H .1300), or DWR Surface Water or Wetland Standards or
Riparian Buffer Rules (15A NCAC 2B .0200)7 *
Yes No
3. Cumulative Impacts (DWR Requirement)
3a. Will this project result in additional development, which could impact nearby downstream water quality?*
Yes No
3b. If you answered "no," provide a short narrative description.
This project is not a development project and instead is designed to improve downstream water quality by removing the dam and returning the flow
regime to Deep River. Even though the river is classified as a High Quality Water, there are no permanent fills or new impervious surfaces proposed.
4. Sewage Disposal (DWR Requirement)
4a. Is sewage disposal required by DWR for this project?*
Yes No N/A
5. Endangered Species and Designated Critical Habitat (Corps Requirement)
5a. Will this project occur in or near an area with federally protected species or habitat?*
Yes No
5b. Have you checked with the USFWS concerning Endangered Species Act impacts?*
Yes No
5c. If yes, indicate the USFWS Field Office you have contacted.
Asheville
5d. Is another Federal agency involved?*
Yes
What Federal Agency is involved?
USFWS
5e. Is this a DOT project located within Division's 1-8?
Yes No
No Unknown
5f. Will you cut any trees in order to conduct the work in waters of the U.S.?
Yes No
5g. Does this project involve bridge maintenance or removal?
Yes No
5h. Does this project involve the construction/installation of a wind turbine(s)?*
Yes No
51. Does this project involve (1) blasting, and/or (2) other percussive activities that will be conducted by machines, such as jackhammers, mechanized pile drivers, etc.?
Yes No
5j. What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical Habitat?
There are known populations of the CFS immediately below the dam. The applicant has been in coordination with USFWS and WRC for this project.
Attached is the Draft Biological Assessment.
6. Essential Fish Habitat (Corps Requirement)
6a. Will this project occur in or near an area designated as an Essential Fish Habitat?*
Yes No

6b. What data sources did you use to determine whether your site would impact an Essential Fish Habitat? *
The project is in Moore County which is not near any coastal or tidal habitat which would support EFH (i.e. salt marshes, oyster reefs, etc.).
7. Historic or Prehistoric Cultural Resources (Corps Requirement)
7a. Will this project occur in or near an area that the state, federal or tribal governments have designated as having historic or cultural preservation status?*
Yes No
7b. What data sources did you use to determine whether your site would impact historic or archeological resources?*
See attached SHPO letter, dated September 6, 2018, which confirms that the site is not listed as a historic property or within a historic district.
8. Flood Zone Designation (Corps Requirement)
8a. Will this project occur in a FEMA-designated 100-year floodplain?*
Yes No
8b. If yes, explain how project meets FEMA requirements:
A flood study was performed by KBE.
8c. What source(s) did you use to make the floodplain determination?*
FEMA online database: panel 3710864200J, effective on 10/17/2006
Miscellaneous
Please use the space below to attach all required documentation or any additional information you feel is helpful for application review. Documents should be combined into one file when
possible, with a Cover Letter, Table of Contents, and a Cover Sheet for each Section preferred.
Click the upload button or drag and drop files here to attach document
High Falls Dam Removal Supplemental Application Documents.pdf 19.55MB
File must be PDF or KMZ
Comments
Pre -construction Notification (PCN) Application Form
Agent Authorization Form
Figure 1-USGS Site Vicinity Map
Figure 2-Soil Survey Site Vicinity Map
Figure 3 - Wetland Sketch Maps
NCSHPO Project Review Letter
Impact Maps
High Falls Dam Sediment Study (Final)
High Falls Dam Biological Assessment (Draft)
Notice of Intent to File a Permit Application
Signature
By checking the box and signing below, I certify that:
• The project proponent hereby certifies that all information contained herein is true, accurate, and complete to the best of my knowledge and belief'; and
• The project proponent hereby requests that the certifying authority review and take action on this CWA 401 certification request within the applicable reasonable period of time.
• I have given true, accurate, and complete information on this form;
I agree that submission of this PCN form is a "transaction" subject to Chapter 66, Article 40 of the NC General Statutes (the "Uniform Electronic Transactions Act");
I agree to conduct this transaction by electronic means pursuant to Chapter 66, Article 40 of the NC General Statutes (the "Uniform Electronic Transactions Act");
I understand that an electronic signature has the same legal effect and can be enforced in the same way as a written signature; AND
I intend to electronically sign and submit the PCN form.
Full Name:
Nicole J. Thomson
Signature
1666' YI4k4At
Date
1/30/2023

SAGE
ECOLOGICAL
SERVICES
E5
.21116
January 30, 2023
US Army Corps of Engineers
Raleigh Regulatory Office
3331 Heritage Trade Dr., Ste. 105
Wake Forest, NC 27587
Re: High Falls Dam Removal
Request for NWP 53, GC 4273
Sage Project #2018.031
NC Division of Water Resources
401 & Buffer Permitting Unit
512 N. Salisbury St., Archdale Bldg. 91h Flr
Raleigh, NC 27604
On behalf of Pobeda Holdings, LLC (applicant), please find attached a complete application and supplemental
information requesting written concurrence from the US Army Corps of Engineers (USACE) that the activities
associated with the proposed removal of the High Falls Dam (Project) may proceed under Nationwide Permit
(NWP) 53 and General Certification 4273 (GC 4273).
Project Purpose and Location
The Project includes the removal of a low head dam on the Deep River. The +/-19.898-acre tract is located at
1460 NC Highway 22, High Falls, Moore County. The coordinates of 35.478°N, 79.524°W generally correspond
to the center of the Site.
The Site contains a hydroelectric power station, wooded land, and grassy areas. The surrounding properties are
residential and industrial.
Project Detail
The purpose of the project is to remove High Falls Dam. High Falls Dam and the impounded reservoir behind
the dam inhibit natural river flow and prevent natural river conditions of shallow water and rocky outcrops from
being available for aquatic species. Currently, the dam is a barrier to aquatic organisms that limits access to
habitat and isolates populations. The reservoir behind the dam is a man-made lentic system that does not provide
the natural habitat associated with the Deep River.
Access to the Site will be provided via Highway 22 to the east. Heavy equipment typically used for dam removal
projects (e.g., backhoes, bulldozers, vibratory equipment etc.) will be utilized.
There are known populations of Notropis mekistocholas (Cape Fear Shiner) immediately below the dam. The
applicant has been in coordination with US Fish and Wildlife Service (USFWS) and Wildlife Resource
Commission (WRC) for this project and the draft Biological Assessment (BA) is attached.
The Site itself is not listed as a historic property or within a historic district.
Project History
The High Falls project site (Site) includes three parcels totaling approximately 19.9 acres located west of Highway
22 on the north side of the Deep River in High Falls, Moore County, North Carolina. The street address is 1460
NC Highway 22, High Falls, NC 27259. The Site contains a hydroelectric power station, wooded land, and grassy
areas. The surrounding properties are residential and industrial. To the north there is wooded land and a vacant
textile mill, to the east there is wooded land, to the south and west is wooded land and the Deep River. Within
the watershed of the Site, there is 47% forest cover, 24% crop cover, and 5% impervious surface cover.
High Falls Dam Removal Page 1 of 2

Avoidance and Minimization
The purpose of the proposed project is to remove existing impacts to the Deep River by recreating natural
lotic/river conditions at the Site as well as restoring riparian habitat. The proposed impacts are temporary in
nature and will only be for the minimum amount of time required to remove the dam and restabilize the banks.
An NCDEQ approved sediment and erosion control plan will be implemented throughout the duration of the dam
removal project. After equilibrium is reached, seed and straw with seed mixes will be applied to bare areas, and
areas within the floodplain will have livestakes and bare root trees installed according to the restoration plan
included in the engineering plans attached. The removal of the dam will be scheduled to avoid spawning of the
Notropis mekistocholas (Cape Fear Shiner) (May -July).
Project Impacts
Proposed impacts include 43 linear feet of temporary stream impact for the dam removal and 20 linear feet of
temporary stream impact for temporary construction access.
Mitigation
Proposed stream impacts are temporary therefore compensatory mitigation is not required.
If you have any questions, please call me at [phone].
Respectfully submitted:
can Clark Nicole J..Thomson, PWS
Sage Ecological Services, Inc.
Attachments:
Pre -construction Notification (PCN) Application Form
Agent Authorization Form
Figure 1-USGS Site Vicinity Map
Figure 2-Soil Survey Site Vicinity Map
Figure 3 - Wetland Sketch Maps
NCSHPO Project Review Letter
Impact Maps
High Falls Dam Sediment Study (Final)
High Falls Dam Biological Assessment (Draft)
Notice of Intent to File a Permit Application
Sage Ecological Services, Inc.
High Falls Dam Removal Page 2 of 2

SAGE
ECOLOGICAL
SERVICES
T. 2016
AGENT AUTHORIZATION FORM
All Blanks to Be Filled in By the Current Landowner or Blanks to Be Filled in By the Current Landowner or Legal Representative Representative
Name: Pobeda Holdings, LLC
Address: 5014 Hollow Rock Rd.
Durham, NC 27707
Phone: [phone]
Email: jeff�uniqueplacesllc.com
Project Name/Description: High Falls Dam Removal
Sage Project # 2022.001
Date: 06/09/2022
The Department of the Army
U.S. Army Corps of Engineers, Wilmington District
P.O. BOX 1890
Wilmington, NC 28402
Attn:
Field Office:
Re: Wetlands and Streams Related Consulting and Permitting
To Whom It May Concern:
I, the undersigned, the owner or a duly authorized representative of record of the property/properties identified
herein, do authorize representatives of the U.S. Army Corps of Engineers (Corps) to enter upon the property herein
described for the purpose of conducting on -site investigations and issuing a determination associated with Waters
of the U.S. subject to Federal jurisdiction under Section 404 of the Clean Water Act and/or Section 10 of the Rivers
and Harbors Act of 1899. I also hereby designate and authorize Sage Ecological Services to act on my behalf as my
agent in the processing of permit applications, to furnish upon request supplemental information in support of
applications, etc. from this day forward.
This notification supersedes any previous correspondence concerning the agent for this project.
Notice: This authorization, for liability and professional courtesy reasons, is valid only for government
officials to enter the property when accompanied by Sage staff. Please contact Sage to arrange a meeting
prior to visiting the site.
BY: Jeffrey Fisher, Manager of Pobeda Holdings, LLC
Print Name of Landowner or
Legal Representative
BY:
SignatdrYYY Landowner or
Legal Representative

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North Carolina Department of Natural and Cultural Resources
State Historic Preservation Office
Ramona M. Bartos, Administcator
Governor Roy Cooper Office of Archives and History
Secretary Susi H. I Iamilton Deputy Secretary Kevin Cherry
September 6, 2018
Aaron Aho [e-mail]
Unique Places, LLC
PO Box 52357
Durham, NC 27717
Re: High Falls Dam Removal, 1460 NC 22, Deep River, Robbins, Moore County, ER 18-1814
Dear Mr. Aho:
Thank you for your email of August 3, 2018, regarding the above -referenced undertaking. We have reviewed
the submittal and offer the following comments.
There are no known archaeological sites within the proposed project area. Based on our knowledge of the
area, it is unlikely that any archaeological resources that may be eligible for inclusion in the National Register of
Historic Places will be affected by the project. We, therefore, recommend that no archaeological investigation
be conducted in connection with this project.
Based on current information, the High Falls Dam is not eligible for listing on the National Register of Historic
Places, therefore no historic properties will be affected by this project. However, the degree of concern
expressed by High Falls citizens suggests great local significance. We recommend that Unique Places engage in
public outreach to help mitigate affects to the community.
The above comments are made pursuant to Section 106 of the National Historic Preservation Act and the
Advisory Council on Historic Preservation's Regulations for Compliance with Section 106 codified at 36 CFR
Part 800.
Thank you for your cooperation and consideration. If you have questions concerning the above comment,
contact Renee Gledhill -Earley, environmental review coordinator, at 919-807-6579 or
environmental.review&ncdcr.gov. In all future communication concerning this project, please cite the above
referenced tracking number.
Sincerely,
Ramona M. Bartos
cc: James Lastinger, USACE Regulatory Specialist, Tames.c.lastinger&usace.armymil
Location: 109 East Jones Street, Raleigh NC 27601 Mailing Address: 4617 Mail Service Center, Raleigh NC 27699-4617 Telephone/Fax: [phone]-6599

High Falls Dam Sediment Capacity and Fate Modeling
A sediment transport study was performed to assess existing conditions, predict downstream
changes in the Deep River, and optimize recovery with a removal scenario of High Falls Dam.
Findings detail potential downstream changes to the morphology and bed material of the Deep
River. Recommendations are provided to guide the removal and river recovery efforts.
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Introduction
Unique Places is working with the US Fish and Wildlife Service (USFWS) to plan the removal of High Falls
Dam on the Deep River. The dam has out -lived its useful life and is a barrier to aquatic passage. The
reach of river immediately downstream of the dam is excellent habitat for several endangered species of
mussels and fish, including the Cape Fear Shiner. However, the dam presents a barrier to these species,
cutting off miles of potential aquatic habitats and disrupting sediment continuity. As a part of the
removal investigation, a sediment sampling, modeling, and analysis was completed to predict the short -
and long-term dynamics following the proposed dam removal scenario. Sediment samples were taken
from a stable section upstream of the impoundment, interior to the impoundment, and downstream of
the dam. These sediment samples were used to characterize the morphology and bed material in both
upstream and downstream reaches. Finally, a riverine sediment model was used to predict river profile
and bed material changes after dam removal. Interpretation of these results can be used to anticipate
habitat changes and plan a potential removal process. This report details methods used in the study and
results of each phase of the analysis.
Results Summary
A brief summary of the study results is provided below. These results are detailed further in the report.
1) The amount of sediment trapped behind the dam is small compared to the flow and sediment
transport capacity of Deep River. This indicates much of the sediment that is being delivered
simply passes the dam and already flows downstream. The small amount of sediment that is
trapped should be easily redistributed and moved after a dam removal.
2) Simulations indicate that, with normal flows, the trapped sediment will be flushed in a matter of
months. Storms following the removal could mean this adjustment occurs even sooner.
3) River bed changes downstream post dam removal will largely be unnoticeable. Over the long
term, there are some areas along the river margins that may no longer receive flow and will
accumulate deposits. This would be a return to a pre -dam river configuration.
4) Based on these results, a single-phase dam removal is recommended. The results of the study
support allowing trapped sediments to be naturally flushed downstream.
5) The final dam removal plan should include monitoring so that new river banks may be stabilized
once initial, natural adjustments are completed. The plan may also include efforts to address
endangered species in side channels that will be abandoned downstream of the dam.

Background Data
High Falls Dam is a low head, run of river dam located near High Falls, NC. The dam was built in 1900 and
was in use to generate hydropower until 2018. Hurricane Florence brought record flows at the dam and
the facility suffered tremendous damage. The dam is listed as being 9 feet tall and having a normal
reservoir surface area of 5 acres. The total dam width is approximately 800 feet with the main overflow
section being 300 feet. Our measurements show the dam being 12-15 feet tall and having a normal pool
area of 20 acres (water level at the top of dam). The potential removal will reconnect approximately 19
miles of the Deep River and many miles of tributaries to the next dam upstream in Coleridge, NC.
Figure 1. View of High Falls Dam main overflow in High Falls, NC in July 2018.
K

Study Background
This sediment modeling study included a combination of field work and sediment model simulations
using HEC-RAS 5.0.5. The field work required for this modeling study included depth and bed material
characterization upstream and downstream of High Falls Dam. These data were supplemented with
LiDAR data and existing HEC-RAS cross sections. In addition, sediment samples were taken to describe
bed material in the reservoir area. Sediment samples were analyzed for grain size distribution at a
professional soils lab (Appendix). Sample analysis showed that the majority of the trapped
impoundment sediment is made up of gravelly sand. The downstream reaches consisted of material
from gravels to bedrock. It is clear that some finer materials are trapped in the downstream reach. This
is evidenced by aquatic weeds and vegetation that can be found during the low flow growing season.
The upstream reaches consist of fine gravel and cobble with larger stone and boulders present.
Watershed Analysis
The NC 2004 Cape Fear River Basinwide Assessment Report provides an excellent description of the
entire Deep River Watershed. A few pages from this report are provided in Appendix A. The Deep River
spans 116 river miles and contains 16 small dams. Rolling, piedmont terrain and rocky river beds are
generally characteristic of the Deep. The watershed is largely rural, with a few smaller towns and urban
areas. River stressors include nutrients from non -point sources and wastewater treatment plants. The
watershed to High Falls Dam totals 801 square miles. This large watershed extends from Kernersville, NC
at the northern edge, south through High Point and Asheboro, and finally to the project site. The
watershed includes several moderately sized urban areas, but remains mostly in forest (47%) or
agricultural production (24%).
Stream Gage Data
Data from three US Geological Survey (USGS) stream gaging stations is available along the Deep River.
The nearest station was only active for three years (1994-1996) and was near Glendon, just downstream
of the project site. The nearest upstream site is on the Deep River at Ramseur. This location has a
watershed area of 349 square miles. This station has an excellent record of flow data available beginning
in 1923. A further downstream station can also be found near Moncure, NC. This is the furthest
downstream station on the Deep and has a watershed area of 1,434 square miles. Data is available from
this site going back to 1940. Summary statistics and daily flow data were obtained and analyzed for each
of these sites. Watershed statistics were then calculated for High Falls Dam using a ratio of the Ramseur
and Moncure gage station data based on watershed size. The entire dataset was used to develop an
annual flow duration curve. The curve was later combined to form an annual sediment transport load.
Time series estimates of dry, average, and wet years were created by using the 25%, 50%, and 75%
discharges. These data were prepared and used with both annual and long-term sediment transport
analysis.

High Falls Dam Watershed Land Cover
0 5 '10
Legend
Stream Stats
o High Falls Dam
0 Developed Open Space 0 Forest
Drained Area 801 sq miles
Longest Flow Path 81.176 mi
Longest Flow Path
0 Developed Low Intensity 0 Shrubland
Mean Annual Precip 47 in
Q Watershed
0 Developed Med Intensity 0 Herbaceous
Crop Cover 24.028%
Land Cover
Developed High Intensity 0 Planted/Cultivated
Forest Cover 46.964%
0 Open Water
0 Barren Land 0 Wetlands
Impervious Cover 4.47/0
Wetland Cover 0.532%
Kris Bass Engineering
High Falls Dam Removal
www.kbeng.org
KRIS BASS
919.960.1552
Moore County, North Carolina
E N G I N E E N I N G

High Falls Dam Flow Time Series
3000
Dry Year
2500 Average Year
Wet Year
200o
V
a7
by
1500
V
N_
1000
500
0
12/1 1/1 2/1 3/3 4/3 5/4 6/4 7/5 8/5 9/5 10/6 11/6 1217 1/7
Figure 3. Time series flow data for dry, average, and wet years at High Falls Dam.
Field Data Collection
A field data collection trip was completed to acquire geomorphic and sediment sample information.
Topographic surveying was led by Unique Places and was completed by a Professional Land Surveyor.
Geotechnologies, Inc led the sediment sampling effort and analysis. A report detailing the data
acquisition and analysis efforts is provided in Appendix B.
In general, the reaches upstream of the reservoir were found to have riffle run bed morphology
dominated by large rock and gravels. Deposits sampled in the impoundment area were comprised
mostly of gravelly sand with little to no fine material. Two to three feet of deposits were typical in most
areas. There were a few sample locations progressing upstream where no deposits could be sampled.
These areas are thought to be natural river bed material. The limited deposit depths and the absence of
a delta type deposit at the upstream transition of the reservoir leads us to believe that High Falls Dam
has not been an effective sediment trap. The reach just downstream of the dam is dominated by
bedrock outcroppings with cobble and gravels. The stretch appears to be much wider than the natural
upstream reaches. This is common for river reaches below dams. This over -widening may have been
made worse due to human activity associated with the power station, tailrace, and nearby bridge. The
existence of several islands/mid channel bars may indicate the location of the historic streambank. The
stretch downstream of the dam is also steep compared to other river stretches, which may be indicative
of the name High Falls and a reason for the dam location. This steepness may contribute to the passing
of sediments as almost no sand was found in the main river channel along this area. In comparison,
sand deposits are very observable along the channel margins and floodplain areas. This is an indicator
that substantial sand is transported by the Deep River and makes it over the dam.
M

Figure 4. River and mid -channel bars downstream of High Falls Dam in High Falls, NC in December 2018.
Sediment Depths and Volume
Sediment sampling data was combined with reservoir survey data to prepare a sediment deposition
map. This map was used to calculate the volume of sediment trapped behind the dam. In general, only
2-3 feet of deposits were found throughout the lower portions of the reservoir. However, it is expected
that there are deeper deposits near the dam that could not be sampled due to safety concerns.
Upstream, little to no sand was found and no delta was identified at the river/impoundment transition.
It is our estimate that approximately 37,000 tons of material is trapped behind High Falls Dam. The
amount trapped is small considering the 118-year age of the dam. This amount averages out to less than
1 foot over the entire 20-acre reservoir. Approximately 8,000 tons of this material is located away from
the main spillway and in the channel towards the hydropower gates. This area of the dam is not slated
for removal and this sediment may be stabilized with vegetation. Additional volumes of sediment are
included in the estimate that may become point bars or make up the new river banks after removal.
These areas may not be mobilized if they are stabilized with vegetation prior to substantial flow events.

Sediment Depth
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Figure 5. Sediment depth map of the Deep River upstream of High Falls Dam. Sediment depth was
estimated from sediment sampling data and survey data.
Sediment Analysis and Modeling
The latest public release of HEC-RAS (5.0.5) was used to perform a detailed sediment modeling analysis
on this project. HEC-RAS is a one-dimensional hydraulic model. It is commonly used for sediment
transport investigations and also for dam removal studies. The length of river under study, nature of
sediment, and questions posed also contributed towards choosing this approach. The model extends
from upstream of the reservoir to the bridge downstream of the dam. Cross section data was obtained
from existing HEC-RAS flood models, new survey data, and available LiDAR. Sediment data in the model
was prepared from the sediment sampling completed by Geotechnologies, Inc. Analyzed USGS gage
station data was used to complete both storm and long-term flow time series for analysis.
Sediment transport routines in HEC-RAS were completed using the Meyer Peter Muller equations, the
Yang equations, Exner 5 sorting method, and Ruby fall velocity method. Different equations were used
depending on the purpose of the particular calculation. The Meyer Peter Muller equations are suited for
natural gravel bed rivers so can provide a realistic view of the Deep River. The Yang equations are
particularly suited for the transport of sand and were used to characterize transport of the trapped sand
in the impoundment (Gray and Simoes, 2008). The equations and methods used are common in dam
removal studies, especially those concerned with potential downstream sediment deposition.
L

Sediment Transport Capacity
Transport capacity is an estimate of how much sediment a river can move at different flow rates.
Comparison of these rates for different reaches is a first step in getting an overall view of sediment
balances along a river. It is especially useful in dam removal to determine how well the upstream supply
of sediment (upstream of the area impounded by the dam) is in balance with the capability of the
downstream reaches. This technique has been commonly used as a first step in other dam removal
studies (such as in Randle and Greimann, 2004). For this project, these calculations were completed
using the Meyer Peter Muller equation.
Sediment Transport Capacity
Deep River at High Falls Dam
180W
160W
14000
16
12600
`0
1WW
8000
v
6000
--*--Upstream
40M
-
--*--Dmnstream
2000
0
0 2006 4000 6W0 8W0 10000
12000 14000 16000
Total Cross Section Flow lets)
Figure 6: Transport capacity upstream and downstream of High Falls Dam.
Comparison of the curves upstream and downstream shows that the transport curves upstream and
downstream are relatively similar. The upstream supply does appear to be higher than the downstream
capacity for all flowrates. This means that after dam removal and restoration of the upstream river,
some of the potential material that could be supplied from upstream could be deposited along the
downstream reaches. The reasons for this are further examined and explained in the Discussion and
Interpretation section.
The calculated sediment transport capacity can be combined with an annual flow duration curve to
predict the annual sediment load of the river. The predicted annual sediment transport capacity of the
Deep River is approximately 70,000 tons/year. This prediction compares favorably with published data
from the USGS on the Deep River. Although this report was published in 1976, it does include data
collected on the river in question. They reported Deep River sediment transport of 119 tons/square mile
of drainage area, which would translate to 95,319 tons/year (Simmons, 1976). This number is an
indicator of the river watershed, river size, and slope. The amount of sediment that the stream could
move is large compared to the volume of trapped sediment. In general, this river has the potential to
move several times the amount of sediment that is trapped in just one year. This is both evidence that
7

High Falls Dam has not been an effective sediment trap and that the trapped material can potentially be
moved after a removal.
This estimate of trapped sediment is greater than the amount that may actually be exposed and moved
after a dam removal. As a result, this analysis mainly provides a general illustration of the trapped
sediment and river transport potential. A more detailed sediment transport analysis can further describe
the potential movement of sediment after the dam removal.
Detailed Sediment Modeling
The potential pattern of river recovery and downstream impacts can be examined more closely with
longer term simulations. Simulations of one year duration were performed to better predict the depth
of sediment deposits, duration of increased sediment concentrations, and the overall changes to the
project reach. The simulations were run with the entire dam removed. The maximum depth of erosion
was entered for each cross section. This was done by setting an erosion limit at the base of the dam in
the impoundment and by preventing erosion in the upstream and downstream reaches. This puts a
further focus on the sediment that will erode from the impoundment and that could be deposited
downstream. Grain size distributions were entered using sampling data collected for this study. A flow
data series was used as the upstream boundary condition and a normal depth was used for the
downstream boundary. Sediment boundary conditions included an equilibrium load for the upstream
cross section.
Sediment Modeling Results
The completed results of this phase required a combination of model runs that span from short reaches
to the entirety of the river, under different rain events and varying timeframes. The results presented
here are a compilation of these model results including interpretation based on professional judgment.
As predicted with the initial sediment transport capacity analysis, the Deep River can easily and quickly
move all of the trapped sediment behind High Falls Dam. The river profile shown in Figure 7 illustrates
the predicted profile changes over one year with average flow conditions. With normal flows, the
trapped sediment will mostly be flushed downstream in a matter of months. This timeframe could be
much shorter if a sizable storm event takes place during this time. The model does not show any
sediment build up downstream following the dam removal. This is consistent with expectations based
on the initial capacity analysis findings.
M

Predicted Profile Changes Post Dam Removal over an Average
Year - Deep River at High Falls Dam
290
i Dam
i
i
285
i
i
i
280
o i
M 275 j
i Initial
i
i
i
3 Month
270
1 Year
265
0 2000 4000 6000 8000 10000 12000 14000 16000
Main Channel Distance (ft)
Figure 7: Invert elevation change along the Deep River after removal of High Falls Dam.
A cross section plot shows that the river downstream of the dam will remain almost unchanged (Figure
8). There is no build-up of sediment downstream of the dam after one year under average flow
conditions. Figure 9 shows how the impoundment is expected to change. The trapped sands will be
flushed in a matter of months with regular flows, with little changes expected after that time. Even the
potentially deepest sediment deposits (4 feet) can easily be flushed, while shallower sediments will
likely be moved even faster.
9

420
410
400
390
380
370
360
0 350
+� 340
m
330
w 320
310
300
290
280
270
260 L
0
Cross Section Changes Immediately Downstream of Dam
500 1000
Station (ft)
2000
Figure 8. Deep River cross section changes over 1 year under average flow conditions
immediately downstream of dam (the lines overlap).
288
286
284
282
$ 280
c
278
m
v 276
w
274
272
270
268
0
Cross Section Changes Immediately Upstream of Dam
— Dam Removal — 3 Months 1 Year
50 100 150 200
Station (ft)
250 300 350
Figure 9. Deep River cross section changes over 1 year under average flow conditions in the
impoundment upstream of dam (no changes after 3 months).
10

Discussion and Interpretation
Based on the analysis and modeling results, it should be expected that most of the trapped sand will
move very quickly and the historic river bed will reveal itself in a short amount of time. Any short term
changes to the downstream reach due to the dam removal will almost be unnoticeable. However, there
may be minor or localized changes that should be considered as a part of the project planning. The
location of the dam near a river bend will mean that a point bar will be left as the river level drops. This
area and the recovering banks may take longer to equilibrate. After a few months or a few storms, a
visual inspection would inform the project team whether these areas were stable enough for planting or
in need of additional stabilization efforts. Appendix C contains a sheet from the Project Concept Plan
provided by Wildlands Engineering. The areas shown for riparian seeding should be the primary targets
for this monitoring.
The river reach downstream of High Falls Dam is dramatically over -widened compared to upstream
reaches. The natural river upstream has a width of approximately 130 ft while the downstream reach
approaches 300 feet (Figure 10). This over -widening is the primary reason that the downstream reach
has a lower sediment transport capacity.
Cross Section Comparison
Deep River at High Falls Dam
410
390 Upstream Downstream
370
350
•° 330
M
w 310
290
270
250
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Station (ft)
Figure 11: Upstream and downstream cross section comparison for Deep River
Based on this, is should be expected that this reach may change once sediment continuity is restored.
The channel margins and areas where vegetation already exists would be likely to at least temporarily
trap sediments from upstream (Figure 12). Depending on the timing of flushing storm events, these
areas could develop more permanent vegetation or simply be washed downstream. Once the dam is
removed, areas that now receive regular flows from the hydropower gates will be likely to dry up (Figure
13). The photographs show shallow areas where summer vegetation and rocks could trap incoming
sediments and side channels where deposition should be expected. In general, this should be thought of
as the river returning towards a pre -dam condition.
11

Figure 12. Seasonal vegetation downstream of High Falls Dam. These areas could trap future sediment
and support vegetation.
Figure 13. Side channels on the river left downstream of High Falls Dam after Hurricane Florence. These
areas should be expected to become deposition areas and fill in with vegetation over time.
Figure 13 was taken after Hurricane Florence in 2018. This record storm deposited several inches of
sand along the downstream riparian areas and this can be seen in the photograph. This is further
evidence of the downstream deposition along the boundaries that should be an expected part of the
river long term evolution.
An illustrative sketch of the expected extent of these areas is provided in Figure 15. These areas should
be checked closely for endangered species and considered carefully as part of the removal project.
12

1

Conclusions and Recommendations
The amount of sediment trapped behind High Falls Dam is small in comparison to the average annual
flows and sediment transport capacity of the Deep River. Time series modeling indicates that, with
normal flows, sediment deposits will be quickly moved and flushed downstream. River bed changes
downstream will be negligible following dam removal and as the impoundment recovers.
Calculations and field observations also indicate that the downstream channel margins should be
expected to change over time. There are areas that may not continue to receive flow that will be the
most sensitive to potential deposition and changes.
Based on these results, a single-phase dam removal is recommended. We recommend allowing trapped
sediments to be naturally flushed downstream. A fall removal would provide the historically lowest
baseflows and allow a project completion in time for flushing winter flows. If flow conditions are
suitable, recovering banks would be ready for seeding and stabilization in the following spring. A
monitoring plan is recommended so that new river banks may be stabilized once initial, natural
adjustments are completed. Finally, an assessment and plan focused on downstream side channel areas
is recommended. These areas are likely to dry up and become depositional which will impact any
existing aquatic habitats.
References
Gray, J and J Sim6es, Francisco. (2008). Estimating Sediment Discharge. Sedimentation Engineering -
Processes, Measurements, Modeling, and Practice.
Brunner, G.W. and CEIWR-HEC, 2016. HEC_RAS River Analysis System User's Manual Version 5.0. US
Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center.
Randle, T.J. and Greimann, B., 2004. Sediment Impact Analysis for the Proposed Hemlock Dam Removal
Project. US Department of the Interior Bureau of Reclamation.
Simmons, C. 1976. Sediment Characteristics of Streams in the Eastern Piedmont and Western Coastal
Plan Regions of North Carolina. Geological Survey Water Supply Paper 1708-0.
14

Conclusions and Recommendations
The amount of sediment trapped behind High Falls Dam is small in comparison to the average annual
flows and sediment transport capacity of the Deep River. Time series modeling indicates that, with
normal flows, sediment deposits will be quickly moved and flushed downstream. River bed changes
downstream will be negligible following dam removal and as the impoundment recovers.
Calculations and field observations also indicate that the downstream channel margins should be
expected to change over time. There are areas that may not continue to receive flow that will be the
most sensitive to potential deposition and changes.
Based on these results, a single-phase dam removal is recommended. We recommend allowing trapped
sediments to be naturally flushed downstream. A fall removal would provide the historically lowest
baseflows and allow a project completion in time for flushing winter flows. If flow conditions are
suitable, recovering banks would be ready for seeding and stabilization in the following spring. A
monitoring plan is recommended so that new river banks may be stabilized once initial, natural
adjustments are completed. Finally, an assessment and plan focused on downstream side channel areas
is recommended. These areas are likely to dry up and become depositional which will impact any
existing aquatic habitats.
References
Gray, J and J Sim6es, Francisco. (2008). Estimating Sediment Discharge. Sedimentation Engineering -
Processes, Measurements, Modeling, and Practice.
Brunner, G.W. and CEIWR-HEC, 2016. HEC_RAS River Analysis System User's Manual Version 5.0. US
Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center.
Randle, T.J. and Greimann, B., 2004. Sediment Impact Analysis for the Proposed Hemlock Dam Removal
Project. US Department of the Interior Bureau of Reclamation.
Simmons, C. 1976. Sediment Characteristics of Streams in the Eastern Piedmont and Western Coastal
Plan Regions of North Carolina. Geological Survey Water Supply Paper 1708-0.
14

APPENDIX A

Deep River Drainage (Subbasins 08 -11)
Mainstem
The Deep River originates in eastern Forsyth
County. Draining an area of approximately 1,442
square miles, it flows about 116 miles to its
confluence with the Haw River. The Fall Line,
separating the Piedmont from the Coastal Plain
ecoregions, lies at this confluence. The Deep
River is impounded by more than 16 small dams
between High Point and its confluence. These
reservoirs slow the river's velocity and limit the
system's assimilative capacity. The average slope
along the entire river from the High Point dam to
its mouth is about 5 feet per mile. The fall is rapid
down to the mouth of McLendons Creek, where it
begins to flatten out. The watershed terrain
changes from hilly and rolling in Randolph and
Guilford counties to flat or gently rolling in Moore
and Lee counties with some swampy areas. The
river generally has high banks and few large flood
plains.
Its headwaters, the East and West Forks of the
Deep River, are affected by nonpoint source
runoff, small dischargers, and by low summer
flows. But, there is a contrast between the East
Fork Deep River (urban/residential) and the West
Fork Deep River (agricultural). Macroinvertebrate
data clearly showed more severe water quality
problems in the East Fork (Fair) than in the West
Fork (Good -Fair) in 2003, as it did in 1998. A
TMDL stressor study in the East Fork Deep River
watershed found only one small stream that was
not degraded.
High Point Lake (fed by the East and West Forks
Deep River) and Oak Hollow Lake (on the West
Fork Deep River) have significant and chronic
water quality problems. The reservoirs suffer from
many problems related to cultural eutrophication —
taste and odor problems related to planktonic algal
blooms, problems related to bluegreen algal mats
along the shoreline and in shallow water, and
dissolved oxygen, and aesthetic problems. The
algal blooms resulted in exceedances of water
quality standards for chlorophyll a, dissolved
oxygen, and pH.
Urban areas in the Deep River watershed include
High Point, Randleman, Ramseur, Asheboro, and
Sanford. Municipal wastewater treatment plants in
these cities discharge either directly or indirectly to
the Deep River, and their effluents may make up
the majority of the flow during low flow periods.
Water quality has improved since 1983 and these
improvements have been related to upgrades at
several of the wastewater treatment plants. A
Deep River site at Randleman has consistently
been Good -Fair since 1988 based on benthos
data. Local governments formed the Piedmont
Triad Regional Water Authority (PTRWA) in 1986
with plans to construct Randleman Lake for a
drinking water supply. On August 7, 2001
construction on the Randleman Lake Dam officially
began.
Benthos samples from the Deep River at Ramseur
edged into the Good range in 2003, compared to
Good -Fair since 1986. The benthic community
was not significantly different though. Benthos
data from a Deep River location in Moore County
have consistently indicated an Excellent
bioclassification, as was true in 2003. Most of the
Deep River in Moore County (from Grassy Creek
to NC 42 near Carbonton) is classified as HQW.
Ambient water quality samples are collected from
the Deep River at High Falls and the Deep River at
Carbonton. Slow moving reaches of the river,
including the Carbonton impoundment, are
severely impacted by nutrient loading from
upstream sources.
Deep River Tributaries
The City of High Point's Eastside WWTP is
permitted to discharge 16 MGD to Richland Creek,
just above its confluence with the Deep River. The
fish community rated Richland Creek above the
WWTP Fair and the benthic community rated the
creek Fair below the WWTP in 2003.
A TMDL stressor study in the Hickory Creek
watershed resulted in Fair and Good -Fair ratings,
but the fish community in Hickory Creek was rated
Good. Muddy Creek was given a Fair benthos
rating, but this small stream may have dried up
during the drought. The fish community in Muddy
Creek has fluctuated between Good and Fair. The
fish community in Bull Run was rated Good -Fair.
Hasketts Creek is the next major downstream
tributary and receives the discharge from the
Asheboro WWTP. A TMDL stressor study found
Poor and Fair water quality throughout the
watershed, not just below the WWTP. The stream
receives urban runoff from the City of Asheboro.
Benthos surveys conducted in tributary
catchments from the Town of Ramseur to Moore
County noted Good bioclassifications in 2003 at
Sandy and Richland Creeks. Brush Creek was
sampled at two locations for benthic
macroi nve rte b rates and fish. An upstream site
NCDENR, Division of Water Quality
Basinwide Assessment Report — Cape Fear River Basin - August 2004
22

was rated Good based upon its fish community,
while a site further downstream decreased one
bioclassification from Good in 1998 to Good -Fair
in 2003 based on its benthic macroinvertebrates.
Fork Creek is a new fish community regional
reference site that was rated Good. Evidence of
extreme high flows in the previous six months and
the 2002 drought may have prevented an
Excellent rating.
Sandy Creek Reservoir serves as the major water
supply for the Town of Ramseur and was
classified as eutrophic in 2003. Blooms of diatoms
and bluegreen algae were prevalent during the
summer and caused high chlorophyll a
concentrations that exceeded the water quality
standard. These blooms were also the source of
drinking water taste and odor problems. Dissolved
oxygen saturation levels were also elevated and
exceeded the water quality standard. Carthage
City Lake, the water source for the Town of
Carthage, progressed from oligotrophy in June to
eutrophy in August.
Water quality in upper Cotton Creek is impacted
by the discharge from the Town of Star's WWTP
(0.6 MGD). Ongoing and continuing effluent
toxicity problems in the Town of Star, mostly due
to salts from textile waste, have prompted the
town to explore sewer regionalization with the
Towns of Bisco and Troy to resolve this issue. An
engineering analysis was underway as of April
2004. The bioclassification in Cabin Creek
improved to Good at the Mill Creek confluence
(fish and benthos). Wet, Bear, and Mill Creeks
also had Good benthos or fish ratings. Buffalo
Creek (Subbasin 10) was rated as Good Fair, but
it was not rated in the past possibly due to its
ephemeral qualities. The NCIBI was Good for
Buffalo Creek at the same site. The NCIBI ratings
for Cabin and Indian Creeks decreased from
Excellent to Good and Fair respectively. Cabin
Creek should recover from the effects of highly
fluctuating flows soon. However, Indian Creek, a
former reference site, suffered serious effects from
extensive logging operations and subsequent
scouring effects from high flows in 2003.
The Triassic basin streams, Little Buffalo and
Georges Creeks, will not be rated for benthos until
better criteria are derived for such streams. The
fish community rating at Buffalo Creek (Subbasin
11) improved from Poor to Fair but the number of
fish collected at this site has progressively
declined since 1993.
Rocky River (Subbasin 12)
The Rocky River, a major tributary of the Deep
River, is approximately 35 river miles in length. It
is located mainly within Chatham County. Land
use within its watershed is primarily agriculture,
dairy production, and forest. This watershed is
also in the Carolina Slate Belt. Siler City is the
only urban area. The Rocky River Reservoir is an
impoundment of the Rocky River high in its
watershed that provides water supply for Siler City.
Monitoring results in 2003 characterized the
reservoir as hypereutrophic.
Benthos bioclassifications from locations on the
mainstem of the Rocky River in 2003 indicated
that upstream reaches were either not rated due to
ongoing drought effects (at US 64), were Good -
Fair (at SR 2170), or Good (at US 15-501, near
the confluence with the Deep River). A fish
sample from above the reservoir had a Fair NCIBI.
Several reaches of the lower Rocky River have
been designated Critical Habitat for the Cape Fear
Shiner by the US Fish and Wildlife Service.
Special surveys on Loves Creek have been
conducted to assess the effects of Siler City's
WWTP. Though a TMDL stressor study
suggested that some impairment of Loves Creek
could be attributed to the facility, the primary
sources of impairment lay upstream of the WWTP.
Declines from Good to Good -Fair in Harlands
Creek (benthos) and Bear Creek (fish) were likely
due to delayed recovery from the 2002 drought,
despite higher flows prior to sampling. Tick Creek
was given a Fair NCIBI rating, but a Good -Fair
benthos rating. This may be a result of fish taking
longer to recover from the drought at this site than
the benthos.
Cape Fear River Drainage
Mainstem and Minor Tributaries (Subbasins 07
and parts of 15 - 17)
The mainstem Cape Fear River originates near the
Fall Line and then flows 170 miles through the
Coastal Plain to the Atlantic Ocean. The stream
gradient is higher down to the City of Fayetteville,
than beyond where it then begins to flatten out.
The flat terrain of the Coastal Plain results in many
tributary swamp systems. The drainage area of
the mainstem Cape Fear River is about 6,065
square miles. At its mouth the Cape Fear empties
into the Atlantic Ocean near the Town of Southport
and much of this estuarine area has salinities high
enough for the waters to be classified as shellfish
waters (SA).
NCDENR, Division of Water Quality
Basinwide Assessment Report — Cape Fear River Basin - August 2004
23

Appendix B
17

i
' GeotechnicaI and Construction Materials Testing Services
December 21, 2018
Kris Bass Engineering
625 S. Lakeside Drive
Raleigh, NC 27606
Attn: Mr. Kris Bass, PE
Re: Sampling Report
High Falls Dam
High Falls, North Carolina
GeoTechnologies Project No. 1-18-0494-EA
Mr. Bass:
GeoTechnologies, Inc. has completed the authorized sampling for the above referenced project in High
Falls, North Carolina. It is our understanding that consideration is being given to removal of the existing dam
on the Deep River near High Falls, North Carolina. The dam was constructed as part of the abandoned hydro-
electric facility located just north of the bridge over the Deep River on SR 22. As part of the process to remove
the dam, it is desired to evaluate the make-up of the river bed both downstream and upstream of the dam. This
report presents a brief description of the sampling procedures and the results of the sampling.
Area Geology: The site is located in the Piedmont Physiographic and Geologic Province of North
Carolina. The Piedmont Province is characterized by a gently to steeply sloping topography, rolling hills and
ridge lines, dissected by moderate to well -developed (mature) dendritic type drainage system and drainage
swales, hollows, tributaries, creeks, streams, and rivers. More specially, the site is located within the Carolina
Slate belt with bedrock materials consisting of metamorphosed argillite, mudstone, volcanic sandstone,
conglomerate and volcanic rock. These materials were formed about 570 million years ago during the later
Proterozoic — Paleozoic Era.
Sampling: GeoTechnologies representatives were on -site on December 7, 2018 to evaluate the
condition of the river bed both downstream and upstream of the dam. The river bed was visually evaluated and
samples obtained for further laboratory analysis. Based upon a visual evaluation of the river bed below the
dam, the river bed is primarily comprised of boulders (greater than 12"), cobbles (12" to 3"), gravel and sand
sized particles overlying bedrock. Very little fine grained (silt & clay) sized particles were observed.
Figure 1 shows the approximate sample locations. Samples of the material were obtained at three
locations downstream of the dam. The samples were collected by wading into the river and collecting samples
with a sampling tube or plastic sealable bag. Due to the depth of water upstream of the dam, a canoe with a
small engine was used to navigate the river and obtain samples. An additional seven locations were sampled
with the tube sampler. Three of the locations encountered bedrock and/or boulders/cobbles that could not be
sampled with the sampler. Sand samples were obtained using the tube sampler at the other four locations
upstream of the dam. The table below summarizes the sample locations with latitude and longitude locations.
3200 Wellington Court, Suite 108 - Raleigh, North Carolina 27615 - Phone [phone] - Fax [phone] - www.geotechpa.com

Kris Bass Engineering
Re: High Falls Dam
December 21, 2018
Page: 2
Sample ID
Latitude
Longitude
Notes
S1
35.47856
-79.5217
Sand sample
S2
35.47816
-79.5235
Sand sample
S3
35.47808
-79.52406
Sand sample
S3A
35.47808
-79.52406
Gravel Sample
S4
35.47863
-79.52491
Sand sample, sampler pushed 2 ft to bedrock
S5
35.47805
-79.52540
Sand sample, sampler pushed 2 ft to bedrock
S6
35.47775
-79.52689
Sand sample, sampler pushed 2.5 ft to bedrock
S7
35.47992
-79.52899
No Recovery, rock and boulder bottom
S8
35.48427
-79.52783
No Recovery, rock and boulder bottom
S9
35.48914
-79.53147
Sand sample, sampler pushed 3 ft to bedrock
S10
35.49353
-79.53960
No Recovery, rock and boulder bottom
The recovered samples were transported to our laboratory for sieve analysis in general accordance
with ASTM D-422. The sieve results are attached. Based upon the sieve results, the samples classify as GW,
SW, SP and SM in accordance with the USCS classification system. The table below provides a classification
symbol and description for each sample. Furthermore, based upon the results of our sampling and testing, it
appears that the river bottom appears to transition to a natural condition somewhere between samples S6 and
ST
Sample ID
USCS
Symbol
USCS Description
S1
SW
Well graded sands, gravelly sands with little to no fines.
S2
SP
Poorly graded sands, gravelly sands with little to no
fines.
S3
SW
Well graded sands, gravelly sands with little to no fines.
S3A
GW
Well graded gravels, gravel -sand mixtures with little to
no fines.
S4
SM
Silty sands, sand -silt mixtures.
S5
SW
Well graded sands, gravelly sands with little to no fines.
S6
SM
Silty sands, sand -silt mixtures.
S9
SP
Poorly graded sands, gravelly sands with little to no
fines.
GeoTechnologies,Inc.
`r' �`

Kris Bass Engineering
Re: High Falls Dam
December 21, 2018
Page: 3
Closing: GeoTechnologies, Inc. appreciates the opportunity to have provided you with our services
on this project. Please contact us if you should have questions regarding this report or if we may be of any
further assistance.
Sincerely,
GeoTechnologies, hic.
Mark R. Potratz, P.E.
NC License No. 25955
MRP/pr-dli
Attachments
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Appendix C
17

609LZ
QNV3 S'ICMIM
API
�Id SURUUId
M3uu3e0 `dU!4U Id
Z'Z

Streamlined Consultation Guidance for Restoration/Recovery Projects (RRP):
Format for the Biological Evaluation/Assessment
The attached biological evaluation/assessment (BE/BA) was developed pursuant to the Fish and Wildlife
Service's Streamlined Consultation Guidance for Restoration/Recovery Projects. The BE/BA meets all of
the criteria for an expedited consultation process set forth in that policy document.
Unique Places hereby requests expedited formal consultation for the High Falls Dam Removal Project.
Signature of Requesting Action Agency Official Date

Biological Evaluation/Assessment
High Falls Dam Removal Project
PREPARED AND SUBMITTED BY:
Unique Places
and
Wildlands Engineering, Inc.

Description of the Proposed Restoration/Recovery Action
A. Description of the Restoration/Recovery Obiective(s)
1. Briefly describe the restoration and specific recovery action (citing source document when
applicable) and its intended beneficial impact to the species.
The High Falls Dam was originally built in the late 1800s to provide power for a textile mill and was
expanded in the 1920s to generate hydroelectric power for Hydrodyne Industries. It is located on the
Deep River approximately 3.5 miles downstream of its confluence with Bear Creek and less than half a
mile upstream of the NC Highway 22 Bridge in Moore County, North Carolina (Figure 1). The dam is
being proposed for removal as part of a National Fish and Wildlife Foundation (NFWF) grant to restore
the Deep River from its currently impounded state to a free -flowing state. Removing the dam will
benefit the federally listed Cape Fear Shiner (Notropis mekistocholas).
High Falls Dam and the High Falls Hydroelectric Reservoir (Figure 2) are responsible for the loss of
natural flow and sediment regimes, and shallow water habitat on approximately 19,669 linear feet of
stream ecosystem (16,502 linear feet within the Deep River and 3,167 linear feet of perennial
tributaries). The U.S. Fish & Wildlife Service (USFWS) has designated sections of the Deep River
upstream of the High Falls Reservoir from Fork Creek to 2.5 miles below Moore County Road 1456 as
critical habitat for the Cape Fear Shiner, a federally listed endangered species (USFWS, 1988) (Figure 3).
While the area immediately around High Falls Dam is not listed as critical habitat, the Cape Fear Shiner
has been observed during surveys conducted by the USFWS throughout the Deep River from just below
the High Falls Dam to the Lockville Dam. The non -impounded sections of the Deep River exhibit very
high -quality riverine habitat that supports a diverse collection of aquatic species including the Cape Fear
Shiner and other at -risk species, such as the brook floater (Alasmidonta varicosa), yellow lampmussel
(Lampsilis cariosa), and Savannah lilliput (Toxolasma pullus). The dam represents a significant blockage
to aquatic species ability to disperse freely and exchange genetic material with neighboring populations,
which has historically contributed to declines in the disconnected Cape Fear Shiner populations (USFWS,
1988). Photographs of the area are provided in Appendix A. While the surveys conducted by the North
Carolina Wildlife Resources Commission (NCWRC) and the USFWS show observations of the Shiner have
become more common above and below High Falls Dam in recent years, the populations are still
segmented (Appendix B). Removal of the blockage created by the dam to allow for genetic exchange
between populations would be of substantial long-term benefit to aquatic communities including the
Cape Fear Shiner.
The recovery goals for the Cape Fear Shiner, as listed in the 1988 USFWS report, are:
1. Protection of existing populations and successful establishment of reintroduced populations and
current habitat;
2. Evaluating feasibility of introducing species into historic habitat;
3. Searching for additional suitable habitat for re -introduction;
4. Monitoring existing populations biannually; and
5. Evaluating the recovery program on an annual basis.
The removal of the High Falls Dam and restoration of the Deep River in the vicinity of the dam will
address the habitat recovery goals of the Cape Fear Shiner listed above. Post -dam removal, the
previously impounded stretch of the Deep River will return to its historic shallow and rocky state. This
will immediately provide 3.13 additional miles of historic habitat for the Cape Fear Shiner and connect
existing habitat and known populations of the species. This expansion of available habitat is expected to
be naturally repopulated as Shiners move into the area from both the upstream and downstream
populations.

The USFWS's recent Species Status Assessment (SSA) for the Cape Fear Shiner (T. Augspurger, pers. comm.,
June 2022) documents that dams are one of the most significant limiting factors for the species. Appendix A
of the SSA contains results of 2020 Cape Fear Shiner surveys and analyses of factors influencing Cape Fear
Shiner presence and abundance. It shows Cape Fear Shiner abundance was negatively correlated with the
presence of dams. Potential future conditions are modeled in the SSA which projects increased viability of
Cape Fear Shiner following High Falls Dam removal by enhancement of connectivity, increasing the extent of
occupied habitat, and increasing abundance.
In November 2021, the USFWS listed the Atlantic Pigtoe (Fusconaia masoni) as threatened (USFWS, 2021).
The Atlantic Pigtoe historically could be found from Georgia to Virginia, but is now currently only found in
North Carolina and Virginia in the Ridge and Valley, Piedmont, and Coastal Plain physiographic regions. The
Atlantic Pigtoe can inhabit medium to large streams and rivers. They require clean, moderate flowing waters
with coarse sand and gravel substrate. The Atlantic Pigtoe prefers excellent water quality with no silt or fine
substrates. They can often be found at the downstream edge of riffle areas (NCWRC, 2022). Designated
critical habitat for the Atlantic Pigtoe occurs about nine miles upstream from the High Falls Dam. This critical
habitat includes the downstream portion of Richland Creek to its confluence with the Deep River, the Deep
River from its confluence with Richland Creek to its confluence with Brush Creek, and about three miles of
Brush Creek from its confluence with the Deep River. Currently, there are two known occurrences of this
species in the Deep River near High Falls Dam (T. Augspurger, pers. comm., June 2022):
• Deep River downstream of High Falls by —9 river miles, historical record with 1 Atlantic
pigtoe shell found in 1993.
• Fork Creek about 11 miles upstream of the dam, current record with 1 live Atlantic pigtoe
found in 2002.
Due to the excellent mussel habitat and diversity at the High Falls Dam site, particularly below the dam and
towards the NC Highway 22 Bridge, it is possible that Atlantic Pigtoe exist at the site. The Species Status
Assessment for the Atlantic Pigtoe documents that dams may prevent access to habitat and cause genetic
isolation, particularly if host fish are not able to pass in -stream barriers.

2. Include a description of anticipated habitat improvements, and/or expected increases in species
fitness, survivorship, etc. that are consistent with the recovery needs of the species.
The impounded portion of the Deep River,
shown in the photo to the left, is an open,
freshwater, lentic habitat. Water depth is
approximately 8-10 feet at the upstream face
of the dam, gradually decreasing in the side
channel, and gradually increasing in the
upstream direction. The impoundment is
narrow through the majority of the river
length and widens just before the dam as
water is funneled into the side channel.
Habitat is suitable for lentic species of fish,
macroinvertebrates, vegetation, and
waterfowl.
Draining the impoundment and removing the
dam is expected to return the Deep River to its
historic bed conditions. These conditions are likely to mimic those upstream of the impoundment and
downstream of High Falls Dam (pictured right). The river will have wide, shallow waters interspersed
with bedrock outcrops, pools, natural riffle features, and deposits of large woody debris. This is
consistent with the habitat needs of the Cape Fear Shiner.
In addition to geomorphic habitat restoration,
the removal of High Falls Dam will restore many
natural processes that will benefit the Cape Fear
Shiner, Atlantic Pigtoe, and other sensitive
aquatic species.
Water temperature and oxygen levels will
change in the Deep River's impounded reach
once the dam is removed. In a study of the Cape
Fear Shiner by Hewitt et al. (2006), the habitats
with the best survivability and growth rate had
temperatures ranging from 26.4°C to 28.1°C.
The Atlantic Pigtoe requires water
temperatures lower than 35°C (USFWS, 2021).
Since the river will be restored to a shallow
water condition, it is more likely to maintain the
temperature ranges preferred by the Cape Fear
Shiner and Atlantic Pigtoe and provide suitable
habitat for species re-establishment. The
aforementioned study by Hewitt et al. (2006)
indicated the best habitat for Cape Fear Shiner
has a DO range of 5.8 — 12.5 mg/L. The Atlantic
Pigtoe requires a DO level of greater than 3
mg/L (USFWS, 2021). Restoration of a shallow,
free -flowing river will improve habitat
conditions within the vicinity of the impounded
reach by increasing DO levels into a range

preferred by the Shiner and Atlantic Pigtoe.
3. Explain why there is a high certainty that implementation of the proposed action is likely to achieve
its intended restoration/recovery objective under the second Criterion for Inclusion. This explanation
should rely on either a proven track record or a high level of certainty that the habitat improvements
are likely to cause the desired species response.
Dam removals have been performed extensively throughout the United States to remove barriers to
aquatic organism passage and return impounded waters to historic lotic conditions. In North Carolina the
Carbonton Dam was removed under similar conditions and project goals to this project including benefits
to Cape Fear Shiner habitat. The Carbonton Dam was a run of the river hydroelectric dam facility located
on the Deep River approximately nine miles west of Sanford, North Carolina. The concrete buttress dam
was built in 1921, averaged 27 feet in height, and had a crest of 260 feet (Restoration Systems, 2005).
Similarly, the High Falls Dam is a run of the river hydroelectric dam facility located on the Deep River. High
Falls Dam was originally built in the late 1800s but was expanded in the 1920s, is approximately 12-15 feet
in height, and has a crest of 287.4 feet.
The Carbonton Dam removal was part of a NCDEQ-Division of Mitigation Services full delivery project
created to deliver mitigation credits for impacts to waters of the United States. Project goals for the
Carbonton Dam removal were similar to this project and included restoration of a lotic ecosystem and
provision of habitat for the endangered Cape Fear Shiner. The project was monitored for five years post -
dam removal. After two years, the Cape Fear Shiner presence was recorded at eight of their 14
monitoring stations, with most surveyed sites developing habitat conditions favorable to the Shiner
(Restoration Systems, 2010). The project can be considered a success for the restoration of Cape Fear
Shiner habitat.
In the fall of 2018, Hoosier Dam, which was located on the Rocky River 5.5 miles upstream of its
confluence with the Deep River in Chatham County, was also removed. As with the proposed High Falls
Dam removal, the removal of Hoosier Dam was funded by a grant from the National Fish and Wildlife
Foundation with the goal of returning the river to natural conditions which favor the Cape Fear Shiner.
After the dam removal the river channel has been stabilizing and progressing towards pre -dam
conditions. The dam removals in this region are part of a trend toward a larger watershed approach to
improve water quality and habitat in the Cape Fear watershed.
The High Falls Dam removal will occur under similar conditions. It is in the same geographic and
geologic region, with similar potential for restoration of shallow, wide, rocky habitat. Potential risk
factors for the project, such as temporary sedimentation in the main channel and permanent
sedimentation in the side channel downstream of the powerhouse gates, are accounted for in
conservation management measures discussed in Section 1D below. No risk factors are evident that
would inhibit the development of a lotic ecosystem with a variety of habitat niches for aquatic species.
The presence of Cape Fear Shiner in the previously impounded section of the Deep River within two
years of the Carbonton Dam removal indicates that the species will enter adjacent, newly available
habitat. Additionally, Cape Fear Shiner populations have also been expanding upstream of the Hoosier
Dam Removal site on the Rocky River since the dam removal took place in 2018. Their presence has
been noted at upstream monitoring sites at Rives Chapel Church Road (SR 2170), NC 902, and Pittsboro
Goldston Road (SR 1010) by NCWRC in 2020 and 2021 that were believed to be extirpated prior to the
dam removal (Three Oaks Engineering, 2022).
Similarly, the monitoring sites on the Rocky River upstream of the former Hoosier Dam have also shown
increasing diversity of mussel species. Surveys conducted by NCWRC between September 2017 and May
2020 found five species of mussels at NC 902, 7 miles upstream of Hoosier Dam, while surveys

conducted by Three Oaks Engineering in 2021 found six species. At Pittsboro Goldston Road (SR 1010), 3
miles upstream of Hoosier Dam, surveys conducted by NCWRC between August 2018 and May 2020
found six species while surveys conducted by Three Oaks Engineering in 2021 found eight species (Three
Oaks Engineering, 2022). The presence of gravel elimia (Elimia catenaria), an aquatic snail usually found
in swiftly flowing waters, was also noted in 2021 in the former Hoosier Dam impoundment area,
demonstrating a shift to lotic conditions (Three Oaks Engineering, 2022).
4. Describe over what time frame the conservation benefits of the proposed action are expected to
accrue.
The Deep River will experience immediate alteration upon removal of the High Falls dam. The
geomorphology, flow regime, and sediment regime will adjust towards conditions present in the river
prior to dam construction. According to the sedimentation analysis (Appendix D), in just one year the
river has the capacity to move several times the amount of sediment that is currently trapped behind
the dam. It is anticipated that within the first few months, most of the sediment affected by the dam
removal will be flushed through the system as a result from the change in geomorphology (i.e., an
increase in channel slope from the removal of the impoundment). Then, overtime, any remaining
sediment may flush through the system on an episodic basis corresponding to large storm events
(Collins et al., 2017; Pearson et al., 2011). This process is expected to return the Deep River to a shallow
water system with a gravel substrate suitable for the colonization of the Cape Fear Shiner and the
Atlantic Pigtoe.
The Cape Fear Shiner can migrate into the previously impounded section of the Deep River from existing
populations located upstream of the impoundment and downstream of the dam (Figure 3). This may
take place over a number of years, eventually fully connecting the designated critical Shiner habitats

above and below the impoundment. This will greatly expand the available habitat and spawning areas
for the Cape Fear Shiner. The timeframe it may take to reestablish the Shiner population throughout the
former impoundment is unknown; however, there are no projected impacts to the river that would
prevent this progress.
The time frame for potential conservation benefits to Atlantic Pigtoe and other mussel species is
unknown, but some assumptions can be inferred. According to Three Oaks Engineering, it takes at least
five years for freshwater mussels to recolonize in former dam and impoundment areas. This is because
of mussel life history characteristics and also allows time for post -removal recruits to grow to a
sufficient size that can be detected by visual surveys (Three Oaks Engineering, 2022). The Atlantic Pigtoe
requires host fish species such as the Rosefin Shiner (Lythrurus ardens), Creek Chub (Semotilus
atromaculatus), and Longnose Dace (Rhynichthys cataractae) for reproduction (USFWS, 2021). Once the
dam is removed, the host fish will have the ability to migrate into the previously impounded section of
the Deep River from existing populations located upstream of the impoundment and downstream of
the dam. Genetic exchange between mussel beds also occurs via sperm drift and movement of mussels
during high flow events (USFWS, 2021). The dam removal will expand available habitat and provide
connectivity needed for colonization.
Define the Action Area
Construction activities will be isolated to the lower section of the impoundment and the area
immediately surrounding High Falls Dam (approximately 1,000 LF) to perform the dam removal,
streambank stabilization, bed stabilization, and re -vegetation (Figure 4). Revegetation may also take
place upstream in areas affected by the drawdown of the impoundment.
The entirety of the impoundment (with an upstream boundary approximately 1,700 feet below the
confluence with Bear Creek and a downstream boundary at High Falls Dam) will be directly and
indirectly affected by the removal of the High Falls Dam. The impounded area, including tributaries
shown in Figure 4, will be hydrologically affected by the removal of the dam. A lotic flow regime will be
reestablished and the channel cross -sections will alter to adjust to the new hydrology. Shallow, rocky
sections of river may be exposed and the habitat niches will transition from lentic to lotic.
Impacts directly downstream of the dam include loss of water flow in the side channels and sediment
deposition along the left side of the river as the over widened channel adjusts back to pre -dam
conditions. Short term impacts may also occur directly downstream of the dam as the Deep River
adjusts to the geomorphic change in the river following removal of the dam.
Following is the proposed project timeline:
• Collection of sensitive mussel species below the dam and in the side channels for relocation
if directed by NC Wildlife Resource Commission: Prior to dam removal, Fall 2022.
• Divert water through powerhouse gates to draw water down in impoundment: Immediately
prior to dam removal to limit the amount of time water is not flowing over the lower dam
and through the main river channel, Fall 2022.
• Removal of High Falls Dam: Fall 2022
o Actions concurrent with dam removal:
Sediment wedge will begin to be transported downstream (wedge is
gravelly sand);
Once areas appear to have stabilized, seed, mat, and plant those areas;
Stabilize, using structures and grading, areas that do not stabilize on their own;
and

• Re-establish riparian buffer with planting of native woody species.
C. Project Implementation
The following federal agencies are involved in permitting and approving the High Falls Dam Removal
Project. Communication and correspondence with all agencies discussed in Table 1, below, is ongoing.
Tentative dates for pre -application meetings with agencies are included in the table.

Table 1: Federal Agencies involved in High Falls Dam Removal — High Falls Dam Removal Project
Associated Permits/
Federal Agency
submittals
Required Action
Status
Nationwide 53 (dam
Pre -application meeting
removal), Nationwide 27
Coordination and receipt
with USACE to be held insummer
US Army Corps of
(stream restoration
of appropriate permits
Engineers
activities) and/or
prior to dam removal and
2022. Permits to
Nationwide 13 (Bank
restoration activities
be applied for summer
Stabilization)
2022
Submittal of Biological
US Fish and Wildlife
Biological Assessment
Assessment so USFWS can
BA to be submitted to
Service
for the Cape Fear Shiner
submit Biological Opinion
USFWS August 2022.
and Atlantic Pigtoe
to USACE for permitting
Submittal of no -rise
Coordinated with local
Federal Emergency
technical memo prior to
Floodplain Administrator.
Dam removal is exempt
restoration activities and
Kris Bass Engineering
Management Agency
CLOMR post restoration
submitted No -Rise in
activities
April 2019.
The removal of the High Falls Dam will follow the procedure and timeline outlined in Section 1B, above.
Table 2, below, lists the activities associated with the project that are likely to have a temporary or long
term beneficial or adverse impact to the Cape Fear Shiner and the Atlantic Pigtoe.

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D. Conservation Measures
Specific management practices will be put in place for the demolition of High Falls Dam and restoration
of Deep River to avoid and minimize adverse impacts to the Cape Fear Shiner, Atlantic Pigtoe and their
habitat. Plans are not yet final and may need to be adjusted to address unforeseen challenges and their
associated impacts.
Management of Demolition
The timing of demolition is important to minimizing impact on Cape Fear Shiner populations
downstream of the impoundment. Late summer/early fall was targeted for demolition based on
consultation with the USFWS for the following reasons, but may be impacted by permitting timelines:
• Baseflow in the channel is at its lowest between June and September. This allows for better
control over dewatering and limits the likelihood of the impoundment levels rising and falling,
potentially harming aquatic species with the water level fluctuations. Low baseflow conditions
also allow for better access to exposed sediments behind the dam, aiding in mechanical removal
if deemed necessary.
• The late summer/early fall timeframe is after the window of spring reproductive activity when
sensitive life stages associated with spawning and larval development of rare mussels and Cape
Fear Shiner occur.
• Aquatic species surveys are easier in the warmer months. Water temperatures allow for human
access for species surveys and relocations.
• Fall will allow for project completion in time for winter flows to flush excess sediment and leave
banks ready for seeding and stabilization in the spring.
Removal of the High Falls Dam and the restoration of the Deep River will adhere to a permitted erosion
and sediment control plan through the NCDEQ Division of Energy, Mineral, and Land Resources (plan
included in Appendix C). Dam removal will be completed to limit impact and contact of equipment,
sediment, and materials with the riverbed and water column. Water will be routed through the
powerhouse gates as much as possible throughout dam removal, maintaining the water level at
elevation 283 or lower, and leaving access to the dam itself. The dam will be removed down to the
remaining impounded water level starting at the intersection with the millpond dam and working across
to the right bank. The remaining dam will be removed in small vertical sections working back toward the
millpond dam. As material is removed it will be placed in the river within the footprint of the dam itself,
to allow construction equipment to cross the streambed on a concrete pad. Once the dam is fully
deconstructed, the pad and dam refuse will be removed from the river floodplain. Water will then be
turned into the center of the channel. The ability to continue a natural flow regime during dam removal
will reduce potential impact on downstream aquatic species. Not having to utilize pumps protects
aquatic species from being inadvertently pumped through the system. Additional erosion control
features will include silt fence along any staging and stockpile areas and stabilizing exposed banks with
erosion control matting and temporary and permanent seed.
E. Monitoring and Reporting Plan
Monitoring of the Cape Fear Shiner will take place for three years following removal of the dam to
document project success. Four monitoring locations along the Deep River, above and below the dam,
will be chosen in consultation with the USFWS and NCWRC during the Biological Opinion process. If
possible three monitoring locations nearby with existing survey data will be chosen for comparison. The
fourth will be within the previously impounded reach.
Monitoring will be conducted via seining suitable habitats for a standard time duration and number of
S-1

seining efforts (to be determined). All monitoring will be performed by a qualified and permitted crew
once a year for up to three years. If Cape Fear Shiner are detected at the three locations outside of the
impounded area during the first or second year of monitoring, then sampling may be discontinued early.
Sampling in the impounded reach should continue for the full three years.
II. Status of the Species and Critical Habitat in the Action Area- Environmental Baseline
Table 3: Federally Listed Species Status — High Falls Dam Removal Project
Species
Habitat Association
Federal Status
Suitable Habitat
in Action Area
Cape Fear Shiner
Gravel, cobble, and boulder substrate
(Notropis mekistocholas)
around aquatic vegetation found in slow
Endangered
Yes
moving pools, riffles, and slow runs.
Atlantic Pigtoe
Course sand and gravel substrate at the
Threatened
Yes
(Fusconaia masoni)
downstream edge of riffle features.
Suitable habitat for the Cape Fear Shiner is located within the Action Area for this project but there is no
designated critical habitat in the Action Area. The nearest downstream designated critical habitat is over
20 miles downstream. The suitable habitat area is located at the base of the dam and continues
downstream of the project. The Cape Fear Shiner habitat upstream of the impoundment will not be
impacted by the activities associated with this project.
Suitable habitat for the Atlantic Pigtoe may be located within the Action Area for this project, but there
is no designated critical habitat in the Action Area or downstream of the Action Area on the Deep River.
Critical habitat for the Atlantic Pigtoe upstream of the Action Area will not be impacted by activities
associated with this project.
A. Notropis mekistocholas (Cape Fear Shiner)
The Notropis mekistocholas, endemic to the Cape Fear River basin, has sustained segmented sub -
populations for several decades; however, environmental stressors are still contributing to the
species decline. Dams and impoundments that create habitat fragmentation and degradation are the
primary culprit for these restricted sub -populations. Currently, the High Falls Dam and its
impoundment is hindering potential connectivity for the Cape Fear Shiner. Limited genetic variation
can be detrimental to the survivability of a population. Considering the life span of the Cape Fear
Shiner is approximately 2-3 years, both existing and developing stressors prevent research and
monitoring opportunities to learn more about their behavior, biology, and ecology.
The Cape Fear Shiner has not been found in the impoundment; however, populations have been
confirmed upstream and downstream. In 2020, the NCWRC conducted a rangewide survey for the Cape
Fear Shiner. The species was confirmed in the mainstem of the Deep River from High Falls Dam to
Glendon -Carthage Rd., which was kayaked with three individual sampling stops. Adults and juvenile
Cape Fear Shiners were observed, indicating successful recruitment, at two sites (T. Augspurger, pers.
comm., June 2022). Currently, the High Falls Dam has altered the riverine habitat resulting in
demographic consequences for the aquatic species, especially the Cape Fear Shiner.
Within confirmed locations, the Cape Fear Shiner has been seined in shallow waters around American
water -willow (Justicia americana). Emergent vegetation provides mesohabitats serving as refuge,
possible food source and locations for depositing and attaching eggs to the substrate associated around
17

willow beds and other riparian vegetation.
The existing lentic ecosystem of the High Falls impoundment has engulfed all microhabitats which
are necessary for distribution and reproduction of the Cape Fear Shiner and similar species.
Furthermore, impoundments act as a reservoir for predators such as the Roanoke bass (Ambloplites
cavifrons), crappie (Pomoxis sp.) and the flathead catfish (Pylodictis olivaris), which is an introduced
obligate carnivorous species (Hewitt et al., 2009 and USFWS, 1988). While the adult catfish do not
occupy the same habitat as the Cape Fear Shiner, the juvenile catfish do and could pose a potential
threat. Dams also act as a holding tank for contaminants which ultimately affect water quality.
Suitable habitats required for early development may be essential for this species' success. The Cape
Fear Shiner has been found in slow pools, shallow side waters and run/riffle complexes throughout
their range indicating velocity breaks with healthier water quality and various depths with mixed
substrates are indicative of suitable habitat for the life stages of this species (USFWS, 1988).
Removal of the High Falls Dam and restoring riverine habitat within a lotic ecosystem will allow natural
features that establish vegetation growth, provide proper spawning grounds, and decrease predation
risks. The project would contribute to long-term conservation efforts of the Cape Fear Shiner and provide
the historical habitat that is necessary to support their population recovery.
B. Cape Fear Shiner Critical Habitat
The Action Area for the High Falls Dam removal project does not contain any designated critical
habitat for the Cape Fear Shiner. The closest upstream critical habitat is in Fork Creek located
approximately 8.23 river miles upstream of the dam, and the closest downstream critical habitat is in
the Deep River below the confluence with the Rocky River. More than 20 miles downstream of High
Falls. Both of these are well -outside of the Action Area.
C. Fusconaia masoni (Atlantic Pigtoe)
The Fusconaia masoni, a native freshwater mussel to the Cape Fear River Basin, currently occupies
only 40% of its historical range (USFWS, 2021). This decrease in abundance and distribution may be
attributed to habitat degradation, pollution, and decreased stream flow (USFWS, 2021). Dams and
impoundments contribute to habitat degradation and fragmentation that impacts the Atlantic Pigtoe.
Currently, the High Falls Dam is hindering potential connectivity of the Atlantic Pigtoe and its host fish
species such as the the Rosefin Shiner (Lythrurus ardens), Creek Chub (Semotilus atromaculatus), and
Longnose Dace (Rhynichthys cataractae) (USFWS, 2021). Host fish and their ability to move freely
through the river system are essential to the reproduction and dispersal of the Atlantic Pigtoe. Genetic
exchange between mussel beds also occurs via sperm drift and movement of mussels during high flow
events (USFWS, 2021). Barriers such as dams prohibit the movement of species and cause genetic
isolation.
Atlantic Pigtoe presence has been noted upstream and downstream of High Falls Dam. A historical
record lists one Atlantic Pigtoe shell that was found in 1993 approximately nine river miles
downstream of the High Falls Dam. Another record lists one live Atlantic Pigtoe in Fork Creek about 11
miles upstream of High Falls Dam in 2002 (T. Augspurger, pers. comm., June 2022). The quality of the
river habitat upstream and downstream of High Falls Dam and the diverse assemblage of mussels
suggests that the site could support Atlantic Pigtoe populations. However, the presence of the High
Falls Dam could be preventing the dispersal of Atlantic Pigtoe populations.
The existing lentic conditions of the High Falls impoundment reduces the availability of potential
microhabitats which are necessary for distribution and reproduction of the Atlantic Pigtoe. The
Atlantic Pigtoe requires riffle habitats with clear flowing water for survival. Dewatering of the
18

impoundment may increase availability of preferred habitat by exposing natural riffle features,
increasing sediment transport, and reverting the river back to lotic conditions.
D. Atlantic Pigtoe Critical Habitat
The Action Area for the High Falls Dam removal project does not contain any designated critical
habitat for the Atlantic Pigtoe. The closest critical habitat for the Atlantic Pigtoe occurs about nine
miles upstream from the High Falls Dam. This critical habitat includes the downstream portion of
Richland Creek to its confluence with the Deep River, the Deep River from its confluence with Richland
Creek to its confluence with Brush Creek, and about three miles Brush Creek from its confluence with
the Deep River. This Atlantic Pigtoe critical habitat will not be impacted by activities in the Action
Area.
Effects of the Action and Cumulative Effects
A. Notropis mekistocholas (Cape Fear Shiner)
Any potential adverse impacts are believed to be temporary. During the demolition process, some
turbidity will occur, and the potential effluent flowrates could push the species downstream. The main
area of concern will be immediately downstream of the dam removal where the impounded sediment
could be temporarily displaced. No fine sediment was found in samples taken from the impoundment
and the river is expected to push excess sediment downstream quickly so turbidity is expected to be
minimal and of short duration. Even so, measures will be set forth to control and prevent mass erosion
or excessive turbidity. For example, seeding will be placed along streambanks to provide streambank
stability and decrease siltation.
There should be very limited take, if any, upstream of the High Falls Dam removal. The gradual lowering
of the impoundment, if possible, would provide opportunity for the Cape Fear Shiner to reach maximum
dispersal distances overtime having a positive impact on population levels. The demolition plan that
limits the time that water is not flowing through the main channel and the scheduling of the project will
minimize adverse impacts to the population downstream. There is the potential for incidental take in
the form of harassment due to machinery and noise in the immediate vicinity of the dam, and potential
harm from transported dam debris or sediment during the demolition/construction and immediate
post -removal stages of the project, but the take is not anticipated to result in any lethality. Further, that
stress / harm should be temporary in duration.
The alteration from a lentic ecosystem to a lotic ecosystem will manipulate the existing habitat and its
function. However, the lotic ecosystem will develop and enhance habitat and the habitat function for
both aquatic and terrestrial species, serving as a wildlife corridor upstream, downstream and across,
whereas the impoundment is currently an obstacle for wildlife species. The action will create a
permanent gain of habitat and habitat function.
The project will develop long-term beneficial impacts by connecting approximately three miles of
improved riverine habitat which will allow for demographic dispersal, genetic diversity and species
richness. Specifically, characteristics such as higher dissolved oxygen levels, stable water temperatures,
consistent hydrologic and sediment regime will establish microhabitats within and around run/riffles
complexes, shallow pools and woody debris throughout the reach. The establishment of new vegetation
along streambanks, on bars and islands of rock outcrops will provide refuge from predation for aquatic
species, including the Cape Fear Shiner, which is crucial for larval and young to reach their first year of
reproductive maturity.
19

The beneficial cumulative effects such as reducing predation, healthier water quality, as well as
extending and connecting the upstream riverine habitat downstream to connect Cape Fear Shiner
populations. The High Falls Dam removal would enhance suitable habitat through the Action Area and
connect areas of critical habitat on Fork Creek to those near the confluence of the Deep River and Rocky
River. This would provide grounds for further research and monitoring of Cape Fear Shiner populations.
The long-term benefits are expected to outweigh the short-term impacts to the species.
B. Cape Fear Shiner Critical Habitat
No areas designated as critical habitat are located within the Action Area. Designated critical habitat is
over 20 miles downstream and outside the area of influence of the project. Therefore, this project and
its temporary in -water work actions should not result in Adverse Modification to designated Cape Fear
Shiner critical habitat.
C. Fusconaia masoni (Atlantic Pigtoe)
Any potential adverse impacts are believed to be temporary and/or limited. During the demolition
process, some turbidity will occur. The main area of concern will be immediately downstream of the
dam removal where the impounded sediment could be temporarily displaced. No fine sediment was
found in samples taken from the impoundment and the river is expected to pulse sediment
downstream quickly so turbidity is expected to be minimal and of short duration. Even so, measures will
be set forth to control and prevent mass erosion or excessive turbidity. For example, seeding will be
placed along streambanks to provide streambank stability and decrease siltation.
There should be very limited take, if any, upstream of the High Falls Dam removal. The dewatering of
the impoundment should not have any effects on the Atlantic Pigtoe as it has not been found in this
area and this species prefers lotic habitat conditions. The dewatering of the impoundment may benefit
the Atlantic Pigtoe by exposing rocky riffle habitat that was previously unavailable. There is the
potential for limited harm or take resulting from transported dam debris or sediment during the
demolition/construction and immediate post -removal stages of the project. Further, that stress / harm
should be temporary in duration.
The alteration from a lentic ecosystem to a lotic ecosystem will manipulate the existing habitat and its
function. However, the lotic ecosystem will develop and enhance habitat and the habitat function for
both aquatic and terrestrial species, serving as a wildlife corridor upstream, downstream and across,
whereas the impoundment is currently an obstacle for wildlife species including Atlantic Pigtoe host fish
species. The action will create a permanent gain of habitat and habitat function.
The project will develop long-term beneficial impacts by connecting approximately three miles of
improved riverine habitat which will allow for demographic dispersal, genetic diversity and species
richness. Specifically, characteristics such as higher dissolved oxygen levels, stable water temperatures,
consistent hydrologic and sediment regime will establish preferred habitats and conditions for the
Atlantic Pigtoe. The re -vegetation of streambanks will provide a forested buffer that serves a role as a
barrier to runoff, cover refugia and nest sites, temperature regulation, and food sources for the benefit
of the Atlantic Pigtoe (USFWS, 2021).
20

D. Atlantic Pigtoe Critical Habitat
No areas designated as critical habitat are located within the Action Area. Designated critical habitat is
over nine miles upstream and outside the area of influence of the project. Therefore, this project and its
temporary in -water work actions should not result in Adverse Modification to designated Atlantic
Pigtoe critical habitat.
IV. Conclusion -Determination of Effect
The removal of the High Falls Dam and restoration of the Deep River is likely to have an overall, long
term, beneficial effect on the Cape Fear Shiner population and available habitat. Demolition and
construction activities discussed herein May Affect and are Likely to Adversely Affect the Cape Fear
Shiner. Incidental take is possible in the form of harassment due to machinery and noise in the
immediate area, and potential harm from transported dam debris or sediment during the
demolition/construction and immediate post -removal stages of the project, but the take is not
anticipated to result in any lethality. There is no designated critical habitat for the Cape Fear Shiner in
the Action Area, and the project will not adversely modify or destroy the designated critical habitat 8.3
miles upstream and over 20 miles downstream of the project areas. Management practices will be used
to prevent incidental take as much as possible.
The removal of High Falls Dam and restoration of the Deep River is likely to have a potential long term
beneficial effect on the Atlantic Pigtoe. Demolition and construction activities discussed herein May
Affect and are Likely to Adversely Affect the Atlantic Pigtoe. Incidental take is possible in the form of
potential harm from transported dam debris or sediment during the demolition/construction and
immediate post -removal stages of the project. There is no designated critical habitat for the Atlantic
Pigtoe in the Action Area, and the project will not adversely modify or destroy the designated critical
habitat nine miles upstream. Management practices will be used to prevent incidental take as much as
possible.
V. List of References and Personal Communications
Collins, M.J., Snyder, N.P., Boardman, G., Banks, W.S.L., Andrews, M., Baker, M.E., Conlon, M., Gellis, A,
McClain, S., Miller, A., and Wilcock, P., 2017. Channel response to sediment release: insights from a
paired analysis of dam removal. Earth Surface Processes and Landforms, doi: 10.1002/esp.4108
Hewitt, Amanda H. et al. 2006. Influence of Water Quality and Associated Contaminants on Survival and
Growth of the Endangered Cape Fear Shiner (Notropis Mekistochoias). Environmental Toxicology and
Chemistry. 25:9. Pp. 2288-2298.
21

Hewitt, Amanda H., Kwak, Thomas J., Cope, W. Gregory, and Pollock, Kenneth H. 2009. Population
Density and Instream Habitat Suitability of the Endangered Cape Fear Shiner. Transactions of the
American Fisheries Society. 136:6. Pp 1439-1457.
NCWRC (North Carolina Wildlife Resources Commission). 2022. Atlantic Pigtoe. Accessed July 5th, 2022.
https://www.ncwildlife.org/Learning/Species/Mollusks/Atlantic-Pigtoe#3028853-life-history
Pearson, A.J., Snyder, N.P., and Collins, M.J., 2011. Rates and processes of channel response to dam
removal with a sand -filled impoundment. Water Resources Research 47:W08504, doi:
10.1029/2010W R009733
Restoration Systems, LLC and Ecoscience Corporation. 2005. Carbonton Dam — Deep River Restoration
Site. Restoration Plan. Project No. 05-235. Accessed May 17, 2017.
https://ncdenr.s3.amazonaws.com/s3fs-
public/Mitigation%20Services/GIS_DATA/CarbontonDam_92268_MP_2005.pdf
Restoration Systems, LLC. 2010. Carbonton Dam — Deep River Watershed Restoration Site 2010 Annual
Monitoring Report (Year 5). NCDMS Project No. D-04012A. Accessed May 17, 2017.
https://ncdenr.s3.amazonaws.com/s3fs-
public/Mitigation%20Services/GIS_DATA/Carbonton%20Dam_92268_%20MY5_2010.pdf
T. Augspurger. Personal Communication. June 2022. USFWS Status Assessment Report for the Cape Fear
Shiner (Notropis mekistocholas), Version 1.0. February 2022. Raleigh, NC.
https://ecos.fws.gov/ServCat/Down load File/215677
Three Oaks Engineering. 2022. Aquatic Species Survey Report, Unique Places to Save: Rocky River.
Durham, NC.
USFWS (U.S. Fish and Wildlife Service). 2021. Species status assessment report for the Atlantic Pigtoe
(Fusconaia masoni). Version 1.4. June, 2021. Atlanta, GA.
USFWS (U.S. Fish and Wildlife Service). 1988. Cape Fear Shiner recovery plan. USFWS, Atlanta.
Wildman, Laura A.S. and James G. MacBroom. 2005. The evolution of gravel bed channels after dam
removal: Case study of the Anaconda and Union City Dam Removals. Geomorphology 71. pp. 245-
262.
VI. List of Appendices
Appendix A: Site Photographs
Appendix B: Summary of Cape Fear Shiner collection history and abundance by river segment
Appendix C: High Falls Dam Removal Project Plans and Erosion and Sediment Control Plan
Appendix D: High Falls Dam Sediment Capacity and Fate Modeling
22

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Figure 1. Vicinity Map
kx�WI LDLAN D S 0 5 10 Miles High Falls Dam Removal Project
ENGI NEERINC-3 I I I I I Biological Assessment
Moore County, NC

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Hi
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Figure 2, Location Map
WILD LANDS 0 750 1,500 Feet High Falls Dam Removal Project
ENC3,1 NE ERINC'-. I I I I I Biological Assessment
Moore County, NC

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Appendix A
Site Photographs

Photo 1: High Falls Dam
(Photo courtesy of Kris Bass Engineering)
Photo 2: Power generation works and High Falls Dam access
High Falls Dam Removal Project
Existing Conditions Photos
Photo 3: Original mill pond flowing
toward power generation works
(Photo courtesy of Kris Bass Engineering)
Appendix A

Photo 4: Deep River Impoundment (High Falls Hydroelectric Reservoir)
(Photo courtesy of Kris Bass Engineering)
Photo 5: Deep River Impoundment (High Falls Hydroelectric Reservoir)
High Falls Dam Removal Project Appendix A
Existing Conditions Photos

Photo 6: Critical Habitat Area for Cape Fear shiner
on the Rocky River upstream of the Hoosier Dam removal site.
Photo 7: Deep River downstream of High Falls Dam
(Photo courtesy of Kris Bass Engineering)
High Falls Dam Removal Project Appendix A
Existing Conditions Photos

Appendix B
Summary of Cape Fear Shiner collection history
and abundance by river segment

Table 3: Summary of Cape Fear Shiner collection history and abundance by river segment
(per Pottern 2009), with additional unpublished data from North Carolina Wildlife
Resources Commission (2008-2016), and USFWS (2018).
River Segment
Miles
1949-1983
1984-1986
1987-2006
2007
2008-2016
2017-
(including
2018
tributaries
Haw River
17.4
none
none
rare
rare
not
not
Saxapahaw to
surveyed
surveyed
Bynum Dam
Bynum Dam to
4.7
rare
none
rare
none
not
not
Jordan Lake
surve ed
surve ed
Robeson Creek to
4.9
uncommon
none
none
none
not
not
Jordan Lake Pool
surveyed
surveyed
Rocky River
16.0
common
rare
none
none
uncommon
not
Siler City to Rocky
surveyed
River Hydro Dam
Rocky River Hydro
5.5
common
common
common
common
common
not
Dam to Deep River
surveyed
Deep River
21.6
none
none
none
none
not
not
Randleman to
surveyed
surveyed
Coleridge Dam
Coleridge Dam to
18.9
none
rare
uncommon
rare
not
common
High Falls Dam
surveyed
High Falls Dam to
21.9
none
rare
uncommon
common
common
common
Carbonton Dam
Carbonton Dam to
22.0
none
uncommon
uncommon
uncommon
common
not
Rocky River
surveyed
Rocky River to
3.5
none
common
common
common
common
not
Lockville Dam
surveyed
Lockville Dam to
0.3
none
uncommon
uncommon
common
not
not
US-1
surveyed
surveyed
Cape Fear River
12.7
none
none
none
none
not
not
Confluence of Cape
surveyed
surveyed
Fear, Deep, and Haw
River to Buckhorn
Dam
Buckhorn Dam to
14.0
uncommon
rare
none
none
not
not
Lillin ton
surve ed
surve ed
Lillington to Erwin
11.5
none
none
none
rare
not
not
surve ed
surve ed
*rare = average 1 to 4 per collection, uncommon = average 5 to 15 per collection, common =
average 16 or more per collection

Appendix C
High Falls Dam Removal Project Plans
and Erosion and Sediment Control Plan

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Appendix D
High Falls Dam Sediment Capacity and Fate Modelling

High Falls Dam Sediment Capacity and Fate Modeling
A sediment transport study was performed to assess existing conditions, predict downstream
changes in the Deep River, and optimize recovery with a removal scenario of High Falls Dam.
Findings detail potential downstream changes to the morphology and bed material of the Deep
River. Recommendations are provided to guide the removal and river recovery efforts.
!0
EAL r'
029434
OPHEIR k\0
1.5.2023
U.S.
FISH & WILDLIFE
SERVICE
u n i q u e
KRIS BASS
paces J E N G I N E E R I N G
��

Introduction
Unique Places is working with the US Fish and Wildlife Service (USFWS) to plan the removal of High Falls
Dam on the Deep River. The dam has out -lived its useful life and is a barrier to aquatic passage. The
reach of river immediately downstream of the dam is excellent habitat for several endangered species of
mussels and fish, including the Cape Fear Shiner. However, the dam presents a barrier to these species,
cutting off miles of potential aquatic habitats and disrupting sediment continuity. As a part of the
removal investigation, a sediment sampling, modeling, and analysis was completed to predict the short -
and long-term dynamics following the proposed dam removal scenario. Sediment samples were taken
from a stable section upstream of the impoundment, interior to the impoundment, and downstream of
the dam. These sediment samples were used to characterize the morphology and bed material in both
upstream and downstream reaches. Finally, a riverine sediment model was used to predict river profile
and bed material changes after dam removal. Interpretation of these results can be used to anticipate
habitat changes and plan a potential removal process. This report details methods used in the study and
results of each phase of the analysis.
Results Summary
A brief summary of the study results is provided below. These results are detailed further in the report.
1) The amount of sediment trapped behind the dam is small compared to the flow and sediment
transport capacity of Deep River. This indicates much of the sediment that is being delivered
simply passes the dam and already flows downstream. The small amount of sediment that is
trapped should be easily redistributed and moved after a dam removal.
2) Simulations indicate that, with normal flows, the trapped sediment will be flushed in a matter of
months. Storms following the removal could mean this adjustment occurs even sooner.
3) River bed changes downstream post dam removal will largely be unnoticeable. Over the long
term, there are some areas along the river margins that may no longer receive flow and will
accumulate deposits. This would be a return to a pre -dam river configuration.
4) Based on these results, a single-phase dam removal is recommended. The results of the study
support allowing trapped sediments to be naturally flushed downstream.
5) The final dam removal plan should include monitoring so that new river banks may be stabilized
once initial, natural adjustments are completed. The plan may also include efforts to address
endangered species in side channels that will be abandoned downstream of the dam.

Background Data
High Falls Dam is a low head, run of river dam located near High Falls, NC. The dam was built in 1900 and
was in use to generate hydropower until 2018. Hurricane Florence brought record flows at the dam and
the facility suffered tremendous damage. The dam is listed as being 9 feet tall and having a normal
reservoir surface area of 5 acres. The total dam width is approximately 800 feet with the main overflow
section being 300 feet. Our measurements show the dam being 12-15 feet tall and having a normal pool
area of 20 acres (water level at the top of dam). The potential removal will reconnect approximately 19
miles of the Deep River and many miles of tributaries to the next dam upstream in Coleridge, NC.
Figure 1. View of High Falls Dam main overflow in High Falls, NC in July 2018.
K

Study Background
This sediment modeling study included a combination of field work and sediment model simulations
using HEC-RAS 5.0.5. The field work required for this modeling study included depth and bed material
characterization upstream and downstream of High Falls Dam. These data were supplemented with
LiDAR data and existing HEC-RAS cross sections. In addition, sediment samples were taken to describe
bed material in the reservoir area. Sediment samples were analyzed for grain size distribution at a
professional soils lab (Appendix). Sample analysis showed that the majority of the trapped
impoundment sediment is made up of gravelly sand. The downstream reaches consisted of material
from gravels to bedrock. It is clear that some finer materials are trapped in the downstream reach. This
is evidenced by aquatic weeds and vegetation that can be found during the low flow growing season.
The upstream reaches consist of fine gravel and cobble with larger stone and boulders present.
Watershed Analysis
The NC 2004 Cape Fear River Basinwide Assessment Report provides an excellent description of the
entire Deep River Watershed. A few pages from this report are provided in Appendix A. The Deep River
spans 116 river miles and contains 16 small dams. Rolling, piedmont terrain and rocky river beds are
generally characteristic of the Deep. The watershed is largely rural, with a few smaller towns and urban
areas. River stressors include nutrients from non -point sources and wastewater treatment plants. The
watershed to High Falls Dam totals 801 square miles. This large watershed extends from Kernersville, NC
at the northern edge, south through High Point and Asheboro, and finally to the project site. The
watershed includes several moderately sized urban areas, but remains mostly in forest (47%) or
agricultural production (24%).
Stream Gage Data
Data from three US Geological Survey (USGS) stream gaging stations is available along the Deep River.
The nearest station was only active for three years (1994-1996) and was near Glendon, just downstream
of the project site. The nearest upstream site is on the Deep River at Ramseur. This location has a
watershed area of 349 square miles. This station has an excellent record of flow data available beginning
in 1923. A further downstream station can also be found near Moncure, NC. This is the furthest
downstream station on the Deep and has a watershed area of 1,434 square miles. Data is available from
this site going back to 1940. Summary statistics and daily flow data were obtained and analyzed for each
of these sites. Watershed statistics were then calculated for High Falls Dam using a ratio of the Ramseur
and Moncure gage station data based on watershed size. The entire dataset was used to develop an
annual flow duration curve. The curve was later combined to form an annual sediment transport load.
Time series estimates of dry, average, and wet years were created by using the 25%, 50%, and 75%
discharges. These data were prepared and used with both annual and long-term sediment transport
analysis.

High Falls Dam Watershed Land Cover
0 5 10
us soi
rrc n
N
Legend
Stream Stats
o High Falls Dam
0 Developed Open Space
0 Forest
Drained Area 801 sq miles
Longest Flow Path 81.176 mi
Longest Flow Path
0 Developed Low Intensity
0 Shrubland
Mean Annual Precip 47 in
0 Watershed
0 Developed Med Intensity
0 Herbaceous
Crop Cover 24.028%
Land Cover
Developed High Intensity
0 Planted/Cultivated
Forest Cover 46.964%
0 Open Water
0 Barren Land
0 Wetlands
Impervious Cover 4.47/0
Wetland Cover 0.532%
Kris Bass Engineering High Falls Dam Removal
www.kbeng.org IRIS BASS
919.960.1552 Moore County, North Carolina E N G I N E E R I N G

High Falls Dam Flow Time Series
3000
Dry Year
2500 Average Year
Wet Year
2000
m
1500
V
N
'o
1000
500
0 — -
12/1 1/1 211 3/3 4/3 5/4 6/4 7/5 8/5 9/� 10/6 11/6 1217 1/7
Figure 3. Time series flow data for dry, average, and wet years at High Falls Dam.
Field Data Collection
A field data collection trip was completed to acquire geomorphic and sediment sample information.
Topographic surveying was led by Unique Places and was completed by a Professional Land Surveyor.
Geotechnologies, Inc led the sediment sampling effort and analysis. A report detailing the data
acquisition and analysis efforts is provided in Appendix B.
In general, the reaches upstream of the reservoir were found to have riffle run bed morphology
dominated by large rock and gravels. Deposits sampled in the impoundment area were comprised
mostly of gravelly sand with little to no fine material. Two to three feet of deposits were typical in most
areas. There were a few sample locations progressing upstream where no deposits could be sampled.
These areas are thought to be natural river bed material. The limited deposit depths and the absence of
a delta type deposit at the upstream transition of the reservoir leads us to believe that High Falls Dam
has not been an effective sediment trap. The reach just downstream of the dam is dominated by
bedrock outcroppings with cobble and gravels. The stretch appears to be much wider than the natural
upstream reaches. This is common for river reaches below dams. This over -widening may have been
made worse due to human activity associated with the power station, tailrace, and nearby bridge. The
existence of several islands/mid channel bars may indicate the location of the historic streambank. The
stretch downstream of the dam is also steep compared to other river stretches, which may be indicative
of the name High Falls and a reason for the dam location. This steepness may contribute to the passing
of sediments as almost no sand was found in the main river channel along this area. In comparison,
sand deposits are very observable along the channel margins and floodplain areas. This is an indicator
that substantial sand is transported by the Deep River and makes it over the dam.
:l

Figure 4. River and mid -channel bars downstream of High Falls Dam in High Falls, NC in December 2018.
Sediment Depths and Volume
Sediment sampling data was combined with reservoir survey data to prepare a sediment deposition
map. This map was used to calculate the volume of sediment trapped behind the dam. In general, only
2-3 feet of deposits were found throughout the lower portions of the reservoir. However, it is expected
that there are deeper deposits near the dam that could not be sampled due to safety concerns.
Upstream, little to no sand was found and no delta was identified at the river/impoundment transition.
It is our estimate that approximately 37,000 tons of material is trapped behind High Falls Dam. The
amount trapped is small considering the 118-year age of the dam. This amount averages out to less than
1 foot over the entire 20-acre reservoir. Approximately 8,000 tons of this material is located away from
the main spillway and in the channel towards the hydropower gates. This area of the dam is not slated
for removal and this sediment may be stabilized with vegetation. Additional volumes of sediment are
included in the estimate that may become point bars or make up the new river banks after removal.
These areas may not be mobilized if they are stabilized with vegetation prior to substantial flow events.

Figure 5. Sediment depth map of the Deep River upstream of High Falls Dam. Sediment depth was
estimated from sediment sampling data and survey data.
Sediment Analysis and Modeling
The latest public release of HEC-RAS (5.0.5) was used to perform a detailed sediment modeling analysis
on this project. HEC-RAS is a one-dimensional hydraulic model. It is commonly used for sediment
transport investigations and also for dam removal studies. The length of river under study, nature of
sediment, and questions posed also contributed towards choosing this approach. The model extends
from upstream of the reservoir to the bridge downstream of the dam. Cross section data was obtained
from existing HEC-RAS flood models, new survey data, and available LiDAR. Sediment data in the model
was prepared from the sediment sampling completed by Geotechnologies, Inc. Analyzed USGS gage
station data was used to complete both storm and long-term flow time series for analysis.
Sediment transport routines in HEC-RAS were completed using the Meyer Peter Muller equations, the
Yang equations, Exner 5 sorting method, and Ruby fall velocity method. Different equations were used
depending on the purpose of the particular calculation. The Meyer Peter Muller equations are suited for
natural gravel bed rivers so can provide a realistic view of the Deep River. The Yang equations are
particularly suited for the transport of sand and were used to characterize transport of the trapped sand
in the impoundment (Gray and Simoes, 2008). The equations and methods used are common in dam
removal studies, especially those concerned with potential downstream sediment deposition.

Sediment Transport Capacity
Transport capacity is an estimate of how much sediment a river can move at different flow rates.
Comparison of these rates for different reaches is a first step in getting an overall view of sediment
balances along a river. It is especially useful in dam removal to determine how well the upstream supply
of sediment (upstream of the area impounded by the dam) is in balance with the capability of the
downstream reaches. This technique has been commonly used as a first step in other dam removal
studies (such as in Randle and Greimann, 2004). For this project, these calculations were completed
using the Meyer Peter Muller equation.
Sediment Transport Capacity
Deep River at High Falls Dam
18000
16000
14000
f6
12000
`0
-�
10000
-
a
u
sow
v
v
6000
f Upstream
4900
fDownstream
2000
0
0 2000 4000 6000 8000 10000
12000 14000 16000
Total Cross Section Flow (cfs)
Figure 6: Transport capacity upstream and downstream of High Falls Dam.
Comparison of the curves upstream and downstream shows that the transport curves upstream and
downstream are relatively similar. The upstream supply does appear to be higher than the downstream
capacity for all flowrates. This means that after dam removal and restoration of the upstream river,
some of the potential material that could be supplied from upstream could be deposited along the
downstream reaches. The reasons for this are further examined and explained in the Discussion and
Interpretation section.
The calculated sediment transport capacity can be combined with an annual flow duration curve to
predict the annual sediment load of the river. The predicted annual sediment transport capacity of the
Deep River is approximately 70,000 tons/year. This prediction compares favorably with published data
from the USGS on the Deep River. Although this report was published in 1976, it does include data
collected on the river in question. They reported Deep River sediment transport of 119 tons/square mile
of drainage area, which would translate to 95,319 tons/year (Simmons, 1976). This number is an
indicator of the river watershed, river size, and slope. The amount of sediment that the stream could
move is large compared to the volume of trapped sediment. In general, this river has the potential to
move several times the amount of sediment that is trapped in just one year. This is both evidence that
7

High Falls Dam has not been an effective sediment trap and that the trapped material can potentially be
moved after a removal.
This estimate of trapped sediment is greater than the amount that may actually be exposed and moved
after a dam removal. As a result, this analysis mainly provides a general illustration of the trapped
sediment and river transport potential. A more detailed sediment transport analysis can further describe
the potential movement of sediment after the dam removal.
Detailed Sediment Modeling
The potential pattern of river recovery and downstream impacts can be examined more closely with
longer term simulations. Simulations of one year duration were performed to better predict the depth
of sediment deposits, duration of increased sediment concentrations, and the overall changes to the
project reach. The simulations were run with the entire dam removed. The maximum depth of erosion
was entered for each cross section. This was done by setting an erosion limit at the base of the dam in
the impoundment and by preventing erosion in the upstream and downstream reaches. This puts a
further focus on the sediment that will erode from the impoundment and that could be deposited
downstream. Grain size distributions were entered using sampling data collected for this study. A flow
data series was used as the upstream boundary condition and a normal depth was used for the
downstream boundary. Sediment boundary conditions included an equilibrium load for the upstream
cross section.
Sediment Modeling Results
The completed results of this phase required a combination of model runs that span from short reaches
to the entirety of the river, under different rain events and varying timeframes. The results presented
here are a compilation of these model results including interpretation based on professional judgment.
As predicted with the initial sediment transport capacity analysis, the Deep River can easily and quickly
move all of the trapped sediment behind High Falls Dam. The river profile shown in Figure 7 illustrates
the predicted profile changes over one year with average flow conditions. With normal flows, the
trapped sediment will mostly be flushed downstream in a matter of months. This timeframe could be
much shorter if a sizable storm event takes place during this time. The model does not show any
sediment build up downstream following the dam removal. This is consistent with expectations based
on the initial capacity analysis findings.
E3

Predicted Profile Changes Post Dam Removal over an Average
Year - Deep River at High Falls Dam
290
i Dam
i
i
285
i
i
i
$
280
i
i
c
�
o
275
j
—
,M
i
i
Initial
i
i
Lee
­9­3 Month
270
—0-1 Year
265
0
2000
4000 6000 8000 10000 12000
14000 16000
Main Channel Distance (ft)
Figure 7: Invert elevation change along the Deep River after removal of High Falls Dam.
A cross section plot shows that the river downstream of the dam will remain almost unchanged (Figure
8). There is no build-up of sediment downstream of the dam after one year under average flow
conditions. Figure 9 shows how the impoundment is expected to change. The trapped sands will be
flushed in a matter of months with regular flows, with little changes expected after that time. Even the
potentially deepest sediment deposits (4 feet) can easily be flushed, while shallower sediments will
likely be moved even faster.
9

420
410
400
390
380
370
360
0 350
+� 340
330
w 320
310
300
290
280
270
260
Cross Section Changes Immediately Downstream of Dam
0 500 1000 1500
Station (ft)
2000
Figure 8. Deep River cross section changes over 1 year under average flow conditions
immediately downstream of dam (the lines overlap).
288
286
284
282
280
c
278
v 276
w
274
272
270
268
Cross Section Changes Immediately Upstream of Dam
0 50 150 200 2`
Station (ft)
'00 350
Figure 9. Deep River cross section changes over 1 year under average flow conditions in the
impoundment upstream of dam (no changes after 3 months).
10

Discussion and Interpretation
Based on the analysis and modeling results, it should be expected that most of the trapped sand will
move very quickly and the historic river bed will reveal itself in a short amount of time. Any short term
changes to the downstream reach due to the dam removal will almost be unnoticeable. However, there
may be minor or localized changes that should be considered as a part of the project planning. The
location of the dam near a river bend will mean that a point bar will be left as the river level drops. This
area and the recovering banks may take longer to equilibrate. After a few months or a few storms, a
visual inspection would inform the project team whether these areas were stable enough for planting or
in need of additional stabilization efforts. Appendix C contains a sheet from the Project Concept Plan
provided by Wildlands Engineering. The areas shown for riparian seeding should be the primary targets
for this monitoring.
The river reach downstream of High Falls Dam is dramatically over -widened compared to upstream
reaches. The natural river upstream has a width of approximately 130 ft while the downstream reach
approaches 300 feet (Figure 10). This over -widening is the primary reason that the downstream reach
has a lower sediment transport capacity.
410
390
370
350
c
330
w 310
290
270
250
Cross Section Comparison
Deep River at High Falls Dam
Upstream Downstream
800 1000 1200 1400 1600 1800 2000
Station (ft)
Figure 11: Upstream and downstream cross section comparison for Deep River
Based on this, is should be expected that this reach may change once sediment continuity is restored.
The channel margins and areas where vegetation already exists would be likely to at least temporarily
trap sediments from upstream (Figure 12). Depending on the timing of flushing storm events, these
areas could develop more permanent vegetation or simply be washed downstream. Once the dam is
removed, areas that now receive regular flows from the hydropower gates will be likely to dry up (Figure
13). The photographs show shallow areas where summer vegetation and rocks could trap incoming
sediments and side channels where deposition should be expected. In general, this should be thought of
as the river returning towards a pre -dam condition.
11

Figure 12. Seasonal vegetation downstream of High Falls Dam. These areas could trap future sediment
and support vegetation.
Figure 13. Side channels on the river left downstream of High Falls Dam after Hurricane Florence. These
areas should be expected to become deposition areas and fill in with vegetation over time.
Figure 13 was taken after Hurricane Florence in 2018. This record storm deposited several inches of
sand along the downstream riparian areas and this can be seen in the photograph. This is further
evidence of the downstream deposition along the boundaries that should be an expected part of the
river long term evolution.
An illustrative sketch of the expected extent of these areas is provided in Figure 15. These areas should
be checked closely for endangered species and considered carefully as part of the removal project.
12

ledges/Bedrock
i:ure 15. Hi: Fa s Dam — Potentia a•itat c an:es an• sensitive areas •ost •am remova

Conclusions and Recommendations
The amount of sediment trapped behind High Falls Dam is small in comparison to the average annual
flows and sediment transport capacity of the Deep River. Time series modeling indicates that, with
normal flows, sediment deposits will be quickly moved and flushed downstream. River bed changes
downstream will be negligible following dam removal and as the impoundment recovers.
Calculations and field observations also indicate that the downstream channel margins should be
expected to change over time. There are areas that may not continue to receive flow that will be the
most sensitive to potential deposition and changes.
Based on these results, a single-phase dam removal is recommended. We recommend allowing trapped
sediments to be naturally flushed downstream. A fall removal would provide the historically lowest
baseflows and allow a project completion in time for flushing winter flows. If flow conditions are
suitable, recovering banks would be ready for seeding and stabilization in the following spring. A
monitoring plan is recommended so that new river banks may be stabilized once initial, natural
adjustments are completed. Finally, an assessment and plan focused on downstream side channel areas
is recommended. These areas are likely to dry up and become depositional which will impact any
existing aquatic habitats.
References
Gray, J and J Sim6es, Francisco. (2008). Estimating Sediment Discharge. Sedimentation Engineering -
Processes, Measurements, Modeling, and Practice.
Brunner, G.W. and CEIWR-HEC, 2016. HEC_RAS River Analysis System User's Manual Version 5.0. US
Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center.
Randle, T.J. and Greimann, B., 2004. Sediment Impact Analysis for the Proposed Hemlock Dam Removal
Project. US Department of the Interior Bureau of Reclamation.
Simmons, C. 1976. Sediment Characteristics of Streams in the Eastern Piedmont and Western Coastal
Plan Regions of North Carolina. Geological Survey Water Supply Paper 1708-0.
14

Conclusions and Recommendations
The amount of sediment trapped behind High Falls Dam is small in comparison to the average annual
flows and sediment transport capacity of the Deep River. Time series modeling indicates that, with
normal flows, sediment deposits will be quickly moved and flushed downstream. River bed changes
downstream will be negligible following dam removal and as the impoundment recovers.
Calculations and field observations also indicate that the downstream channel margins should be
expected to change over time. There are areas that may not continue to receive flow that will be the
most sensitive to potential deposition and changes.
Based on these results, a single-phase dam removal is recommended. We recommend allowing trapped
sediments to be naturally flushed downstream. A fall removal would provide the historically lowest
baseflows and allow a project completion in time for flushing winter flows. If flow conditions are
suitable, recovering banks would be ready for seeding and stabilization in the following spring. A
monitoring plan is recommended so that new river banks may be stabilized once initial, natural
adjustments are completed. Finally, an assessment and plan focused on downstream side channel areas
is recommended. These areas are likely to dry up and become depositional which will impact any
existing aquatic habitats.
References
Gray, J and J Sim6es, Francisco. (2008). Estimating Sediment Discharge. Sedimentation Engineering -
Processes, Measurements, Modeling, and Practice.
Brunner, G.W. and CEIWR-HEC, 2016. HEC_RAS River Analysis System User's Manual Version 5.0. US
Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center.
Randle, T.J. and Greimann, B., 2004. Sediment Impact Analysis for the Proposed Hemlock Dam Removal
Project. US Department of the Interior Bureau of Reclamation.
Simmons, C. 1976. Sediment Characteristics of Streams in the Eastern Piedmont and Western Coastal
Plan Regions of North Carolina. Geological Survey Water Supply Paper 1708-0.
14

APPENDIX A

Deep River Drainage (Subbasins 08 -11)
Mainstem
The Deep River originates in eastern Forsyth
County. Draining an area of approximately 1,442
square miles, it flows about 116 miles to its
confluence with the Haw River. The Fall Line,
separating the Piedmont from the Coastal Plain
ecoregions, lies at this confluence. The Deep
River is impounded by more than 16 small dams
between High Point and its confluence. These
reservoirs slow the river's velocity and limit the
system's assimilative capacity. The average slope
along the entire river from the High Point dam to
its mouth is about 5 feet per mile. The fall is rapid
down to the mouth of McLendons Creek, where it
begins to flatten out. The watershed terrain
changes from hilly and rolling in Randolph and
Guilford counties to flat or gently rolling in Moore
and Lee counties with some swampy areas. The
river generally has high banks and few large flood
plains.
Its headwaters, the East and West Forks of the
Deep River, are affected by nonpoint source
runoff, small dischargers, and by low summer
flows. But, there is a contrast between the East
Fork Deep River (urban/residential) and the West
Fork Deep River (agricultural). Macroinvertebrate
data clearly showed more severe water quality
problems in the East Fork (Fair) than in the West
Fork (Good -Fair) in 2003, as it did in 1998. A
TMDL stressor study in the East Fork Deep River
watershed found only one small stream that was
not degraded.
High Point Lake (fed by the East and West Forks
Deep River) and Oak Hollow Lake (on the West
Fork Deep River) have significant and chronic
water quality problems. The reservoirs suffer from
many problems related to cultural eutrophication —
taste and odor problems related to planktonic algal
blooms, problems related to bluegreen algal mats
along the shoreline and in shallow water, and
dissolved oxygen, and aesthetic problems. The
algal blooms resulted in exceedances of water
quality standards for chlorophyll a, dissolved
oxygen, and pH.
Urban areas in the Deep River watershed include
High Point, Randleman, Ramseur, Asheboro, and
Sanford. Municipal wastewater treatment plants in
these cities discharge either directly or indirectly to
the Deep River, and their effluents may make up
the majority of the flow during low flow periods.
Water quality has improved since 1983 and these
improvements have been related to upgrades at
several of the wastewater treatment plants. A
Deep River site at Randleman has consistently
been Good -Fair since 1988 based on benthos
data. Local governments formed the Piedmont
Triad Regional Water Authority (PTRWA) in 1986
with plans to construct Randleman Lake for a
drinking water supply. On August 7, 2001
construction on the Randleman Lake Dam officially
began.
Benthos samples from the Deep River at Ramseur
edged into the Good range in 2003, compared to
Good -Fair since 1986. The benthic community
was not significantly different though. Benthos
data from a Deep River location in Moore County
have consistently indicated an Excellent
bioclassification, as was true in 2003. Most of the
Deep River in Moore County (from Grassy Creek
to NC 42 near Carbonton) is classified as HQW.
Ambient water quality samples are collected from
the Deep River at High Falls and the Deep River at
Carbonton. Slow moving reaches of the river,
including the Carbonton impoundment, are
severely impacted by nutrient loading from
upstream sources.
Deep River Tributaries
The City of High Point's Eastside WWTP is
permitted to discharge 16 MGD to Richland Creek,
just above its confluence with the Deep River. The
fish community rated Richland Creek above the
WWTP Fair and the benthic community rated the
creek Fair below the WWTP in 2003.
A TMDL stressor study in the Hickory Creek
watershed resulted in Fair and Good -Fair ratings,
but the fish community in Hickory Creek was rated
Good. Muddy Creek was given a Fair benthos
rating, but this small stream may have dried up
during the drought. The fish community in Muddy
Creek has fluctuated between Good and Fair. The
fish community in Bull Run was rated Good -Fair.
Hasketts Creek is the next major downstream
tributary and receives the discharge from the
Asheboro WWTP. A TMDL stressor study found
Poor and Fair water quality throughout the
watershed, not just below the WWTP. The stream
receives urban runoff from the City of Asheboro.
Benthos surveys conducted in tributary
catchments from the Town of Ramseur to Moore
County noted Good bioclassifications in 2003 at
Sandy and Richland Creeks. Brush Creek was
sampled at two locations for benthic
macroi nve rte b rates and fish. An upstream site
NCDENR, Division of Water Quality
Basinwide Assessment Report — Cape Fear River Basin - August 2004
22

was rated Good based upon its fish community,
while a site further downstream decreased one
bioclassification from Good in 1998 to Good -Fair
in 2003 based on its benthic macroinvertebrates.
Fork Creek is a new fish community regional
reference site that was rated Good. Evidence of
extreme high flows in the previous six months and
the 2002 drought may have prevented an
Excellent rating.
Sandy Creek Reservoir serves as the major water
supply for the Town of Ramseur and was
classified as eutrophic in 2003. Blooms of diatoms
and bluegreen algae were prevalent during the
summer and caused high chlorophyll a
concentrations that exceeded the water quality
standard. These blooms were also the source of
drinking water taste and odor problems. Dissolved
oxygen saturation levels were also elevated and
exceeded the water quality standard. Carthage
City Lake, the water source for the Town of
Carthage, progressed from oligotrophy in June to
eutrophy in August.
Water quality in upper Cotton Creek is impacted
by the discharge from the Town of Star's WWTP
(0.6 MGD). Ongoing and continuing effluent
toxicity problems in the Town of Star, mostly due
to salts from textile waste, have prompted the
town to explore sewer regionalization with the
Towns of Bisco and Troy to resolve this issue. An
engineering analysis was underway as of April
2004. The bioclassification in Cabin Creek
improved to Good at the Mill Creek confluence
(fish and benthos). Wet, Bear, and Mill Creeks
also had Good benthos or fish ratings. Buffalo
Creek (Subbasin 10) was rated as Good Fair, but
it was not rated in the past possibly due to its
ephemeral qualities. The NCIBI was Good for
Buffalo Creek at the same site. The NCIBI ratings
for Cabin and Indian Creeks decreased from
Excellent to Good and Fair respectively. Cabin
Creek should recover from the effects of highly
fluctuating flows soon. However, Indian Creek, a
former reference site, suffered serious effects from
extensive logging operations and subsequent
scouring effects from high flows in 2003.
The Triassic basin streams, Little Buffalo and
Georges Creeks, will not be rated for benthos until
better criteria are derived for such streams. The
fish community rating at Buffalo Creek (Subbasin
11) improved from Poor to Fair but the number of
fish collected at this site has progressively
declined since 1993.
Rocky River (Subbasin 12)
The Rocky River, a major tributary of the Deep
River, is approximately 35 river miles in length. It
is located mainly within Chatham County. Land
use within its watershed is primarily agriculture,
dairy production, and forest. This watershed is
also in the Carolina Slate Belt. Siler City is the
only urban area. The Rocky River Reservoir is an
impoundment of the Rocky River high in its
watershed that provides water supply for Siler City.
Monitoring results in 2003 characterized the
reservoir as hypereutrophic.
Benthos bioclassifications from locations on the
mainstem of the Rocky River in 2003 indicated
that upstream reaches were either not rated due to
ongoing drought effects (at US 64), were Good -
Fair (at SR 2170), or Good (at US 15-501, near
the confluence with the Deep River). A fish
sample from above the reservoir had a Fair NCIBI.
Several reaches of the lower Rocky River have
been designated Critical Habitat for the Cape Fear
Shiner by the US Fish and Wildlife Service.
Special surveys on Loves Creek have been
conducted to assess the effects of Siler City's
WWTP. Though a TMDL stressor study
suggested that some impairment of Loves Creek
could be attributed to the facility, the primary
sources of impairment lay upstream of the WWTP.
Declines from Good to Good -Fair in Harlands
Creek (benthos) and Bear Creek (fish) were likely
due to delayed recovery from the 2002 drought,
despite higher flows prior to sampling. Tick Creek
was given a Fair NCIBI rating, but a Good -Fair
benthos rating. This may be a result of fish taking
longer to recover from the drought at this site than
the benthos.
Cape Fear River Drainage
Mainstem and Minor Tributaries (Subbasins 07
and parts of 15 - 17)
The mainstem Cape Fear River originates near the
Fall Line and then flows 170 miles through the
Coastal Plain to the Atlantic Ocean. The stream
gradient is higher down to the City of Fayetteville,
than beyond where it then begins to flatten out.
The flat terrain of the Coastal Plain results in many
tributary swamp systems. The drainage area of
the mainstem Cape Fear River is about 6,065
square miles. At its mouth the Cape Fear empties
into the Atlantic Ocean near the Town of Southport
and much of this estuarine area has salinities high
enough for the waters to be classified as shellfish
waters (SA).
NCDENR, Division of Water Quality
Basinwide Assessment Report — Cape Fear River Basin - August 2004
23

Appendix B
17

' Geotechnical and Construction Materials Testing Services
December 21, 2018
Kris Bass Engineering
625 S. Lakeside Drive
Raleigh, NC 27606
Attn: Mr. Kris Bass, PE
Re: Sampling Report
High Falls Dam
High Falls, North Carolina
GeoTechnologies Project No. 1-18-0494-EA
Mr. Bass:
GeoTechnologies, Inc. has completed the authorized sampling for the above referenced project in High
Falls, North Carolina. It is our understanding that consideration is being given to removal of the existing dam
on the Deep River near High Falls, North Carolina. The dam was constructed as part of the abandoned hydro-
electric facility located just north of the bridge over the Deep River on SR 22. As part of the process to remove
the dam, it is desired to evaluate the make-up of the river bed both downstream and upstream of the dam. This
report presents a brief description of the sampling procedures and the results of the sampling.
Area Geology: The site is located in the Piedmont Physiographic and Geologic Province of North
Carolina. The Piedmont Province is characterized by a gently to steeply sloping topography, rolling hills and
ridge lines, dissected by moderate to well -developed (mature) dendritic type drainage system and drainage
swales, hollows, tributaries, creeks, streams, and rivers. More specially, the site is located within the Carolina
Slate belt with bedrock materials consisting of metamorphosed argillite, mudstone, volcanic sandstone,
conglomerate and volcanic rock. These materials were formed about 570 million years ago during the later
Proterozoic — Paleozoic Era.
Sampling: GeoTechnologies representatives were on -site on December 7, 2018 to evaluate the
condition of the river bed both downstream and upstream of the dam. The river bed was visually evaluated and
samples obtained for further laboratory analysis. Based upon a visual evaluation of the river bed below the
dam, the river bed is primarily comprised of boulders (greater than 12"), cobbles (12" to 3"), gravel and sand
sized particles overlying bedrock. Very little fine grained (silt & clay) sized particles were observed.
Figure 1 shows the approximate sample locations. Samples of the material were obtained at three
locations downstream of the dam. The samples were collected by wading into the river and collecting samples
with a sampling tube or plastic sealable bag. Due to the depth of water upstream of the dam, a canoe with a
small engine was used to navigate the river and obtain samples. An additional seven locations were sampled
with the tube sampler. Three of the locations encountered bedrock and/or boulders/cobbles that could not be
sampled with the sampler. Sand samples were obtained using the tube sampler at the other four locations
upstream of the dam. The table below summarizes the sample locations with latitude and longitude locations.
3200 Wellington Court, Suite 108 -Raleigh, North Carolina 27615 -Phone [phone] -Fax [phone] - www.geotechpa.com

Kris Bass Engineering
Re: High Falls Dam
December 21, 2018
Page: 2
Sample ID
Latitude
Longitude
Notes
S1
35.47856
-79.5217
Sand sample
S2
35.47816
-79.5235
Sand sample
S3
35.47808
-79.52406
Sand sample
S3A
35.47808
-79.52406
Gravel Sample
S4
35.47863
-79.52491
Sand sample, sampler pushed 2 ft to bedrock
S5
35.47805
-79.52540
Sand sample, sampler pushed 2 ft to bedrock
S6
35.47775
-79.52689
Sand sample, sampler pushed 2.5 ft to bedrock
S7
35.47992
-79.52899
No Recovery, rock and boulder bottom
S8
35.48427
-79.52783
No Recovery, rock and boulder bottom
S9
35.48914
-79.53147
Sand sample, sampler pushed 3 ft to bedrock
S10
35.49353
-79.53960
No Recovery, rock and boulder bottom
The recovered samples were transported to our laboratory for sieve analysis in general accordance
with ASTM D-422. The sieve results are attached. Based upon the sieve results, the samples classify as GW,
SW, SP and SM in accordance with the USCS classification system. The table below provides a classification
symbol and description for each sample. Furthermore, based upon the results of our sampling and testing, it
appears that the river bottom appears to transition to a natural condition somewhere between samples S6 and
ST
Sample ID
USCS
Symbol
USCS Description
S1
SW
Well graded sands, gravelly sands with little to no fines.
S2
SP
Poorly graded sands, gravelly sands with little to no
fines.
S3
SW
Well graded sands, gravelly sands with little to no fines.
S3A
GW
Well graded gravels, gravel -sand mixtures with little to
no fines.
S4
SM
Silty sands, sand -silt mixtures.
S5
SW
Well graded sands, gravelly sands with little to no fines.
S6
SM
Silty sands, sand -silt mixtures.
S9
SP
Poorly graded sands, gravelly sands with little to no
fines.
y GevTechnologim, Inc.

Kris Bass Engineering
Re: High Falls Dam
December 21, 2018
Page: 3
Closing: GeoTechnologies, Inc. appreciates the opportunity to have provided you with our services
on this project. Please contact us if you should have questions regarding this report or if we may be of any
further assistance.
Sincerely,
GeoTechnologies, hic.
Mark R. Potratz, P.E.
NC License No. 25955
MRP/pr-dli
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Appendix C
17

is ul

From: Nikki Thomson
To: 401 PreFi le
Cc: Sean Clark; Kim Hamlin
Subject: High Falls Dam Removal; Sage Project No. 2018.31 - Notice of Intent to File a Permit Application
Date: Wednesday, June 1, 2022 3:58:00 PM
This email serves to notify DWR of the intent of Sage Ecological to file a Permit Application for the
High Falls Dam Removal.
Thank you
Nik
Nicole Thomson, PWS
Sage Ecological Services, Inc.
[e-mail]
[phone]