20061752 Ver 1_Complete File_20061215

Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
December 15, 2006
DWQ Project # 06-1752
Avery County
Murray M. White, Jr.
Edgar Tufts Memorial Association
Post Office Box 2196
High Point, NC 27261
Subject Property: Wildcat Lake Dam Repair
Banner Elk, NC
LC?CO?R Q
DEC 2 2 2006
VYET BRANCH
LANDSANDST RMMTER
Approval of 401 Water Quality Certification with Additional Conditions
Dear Mr. White:
You have our approval, in accordance with the attached conditions and those listed
below, to place fill within or otherwise impact 128 linear feet of streams for the purpose
of dam repair and modification at the subject property, as described within your
application received by the N.C. Division of Water Quality (DWQ) on November 7, 2006.
After reviewing your application, we have decided that the impacts are covered by
General Water Quality Certification Number(s) 3494 (GC3494). The Certification(s)
allows you to use Nationwide Permit(s) 3 when issued by the US Army Corps of
Engineers (USACE). In addition, you should obtain or otherwise comply with any other
required federal, state or local permits before you go ahead with your project including
(but not limited to) Erosion and Sediment Control, Non-discharge, and Stormwater
regulations. Also, this approval to proceed with your proposed impacts or to
conduct impacts to waters as depicted in your application shall expire upon
expiration of the 404 or CAMA Permit.
This approval is for the purpose and design that you described in your application. If
you change your project, you must notify us and you may be required to send us a new
application. If the property is sold, the new owner must be given a copy of this
Certification and approval letter and is thereby responsible for complying with all
conditions. If total fills for this project (now or in the future) exceed one acre of wetland
or 150 linear feet of stream, compensatory mitigation may be required as described in
15A NCAC 2H .0506 (h). This approval requires you to follow the conditions listed in
the attached certification and any additional conditions listed below.
The Additional Conditions of the Certification are:
401 Wetlands Certification Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] / FAX [phone] Internet: htto://h2o.enr.state.no.us/ncvoetlands
NonLCarolina
JVaturally
An Equal Opportunity/Affirmative Action Employer- 50% Recycled/10% Post Consumer Paper
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
December 15, 2006.
DWQ Project # 06-1752
Avery County
Murray M. White, Jr.
Edgar Tufts Memorial Association
Post Office Box 2196
High Point, NC 27261
Subject Property: Wildcat Lake Dam Repair
Banner Elk, NC
DEC 2 2 2006
DENR - WATER QUALITY
V4ERANDS AND SToRfflTgR BRANCH
Approval of 401 Water Quality Certification with Additional Conditions
Dear Mr. White:
You have our approval, in accordance with the attached conditions and those listed
below, to place fill within or otherwise impact 128 linear feet of streams for the purpose
of dam repair and modification at the subject property, as described within your
application received by the N.C. Division of Water Quality (DWQ) on November 7, 2006.
After reviewing your application, we have decided that the impacts are covered by
General Water Quality Certification Number(s) 3494 (GC3494). The Certification(s)
allows you to use Nationwide Permit(s) 3 when issued by the US Army Corps of
Engineers (USAGE). In addition, you should obtain or otherwise comply with any other
required federal, state or local permits before you go ahead with your project including
(but not limited to) Erosion and Sediment Control, Non-discharge, and Stormwater
regulations. Also, this approval to proceed with your proposed impacts or to
conduct impacts to waters as depicted in your application shall expire upon
expiration of the 404 or CAMA Permit.
This approval is for the purpose and design that you described in your application. If
you change your project, you must notify us and you may be required to send us a new
application. If the property is sold, the new owner must be given a copy of this
Certification and approval letter and is thereby responsible for complying with all
conditions. If total fills for this project (now or in the future) exceed one acre of wetland
or 150 linear feet of stream, compensatory mitigation may be required as described in
15A NCAC 2H .0506 (h). This approval requires you to follow the conditions listed in
the attached certification and any additional conditions listed below.
The Additional Conditions of the Certification are:
401 Wetlands Certification Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] / FAX [phone] / Internet http://h2o.enr.state.nc.us/ncwetlands
NonithCarolina
Naturally
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Wildcat Lake Dam Repair
Page 2 of 3
December 15, 2006
1. Impacts Approved
The following impacts are hereby approved as long as all of the other specific
and general conditions of this Certification (or Isolated Wetland Permit) are met.
No other impacts are approved including incidental impacts:
I ' Amount
Approved Units Plan Location or Reference
I Stream 93 (feet) Earthen Dam Fill and spillway
I Stream 135 (feet) Outlet Protection
Waters 0.20 (acres) Earthen Dam Fill
2. Erosion & Sediment Control Practices
Erosion and sediment control practices must be in full compliance with all
specifications governing the proper design, installation and operation and
maintenance of such Best Management Practices in order to protect surface
waters standards:
a. The erosion and sediment control measures for the project must be
designed, installed, operated, and maintained in accordance with the most
recent version of the North Carolina Sediment and Erosion Control Planning
and Design Manual.
b. The design, installation, operation, and maintenance of the sediment and
erosion control measures must be such that they equal, or exceed, the
requirements specified in the most recent version of the North Carolina
Sediment and Erosion Control Manual. The devices shall be maintained on
all construction sites, borrow sites, and waste pile (spoil) projects, including
contractor-owned or leased borrow pits associated with the project.
c. For borrow pit sites, the erosion and sediment control measures must be
designed, installed, operated, and maintained in accordance with the most
recent version of the North Carolina Surface Mining Manual.
d. The reclamation measures and implementation must comply with the
reclamation in accordance with the requirements of the Sedimentation
Pollution Control Act.
3. No Waste, Spoil, Solids, or Fill of Any Kind
No waste, spoil, solids, or fill of any kind shall occur in wetlands, waters, or riparian
areas beyond the footprint of the impacts depicted in the Pre-Construction
Notification. All construction activities, including the design, installation, operation,
and maintenance of sediment and erosion control Best Management Practices,
shall be performed so that no violations of state water quality standards, statutes,
or rules occur.

Wildcat Lake Dam Repair
Page 3 of 3
December 15, 2006
4. No Sediment & Erosion Control Measures w/n Wetlands or Waters
Sediment and erosion control measures shall not be placed in wetlands or waters
to the maximum extent practicable. If placement of sediment and erosion control
devices in wetlands and waters is unavoidable, they shall be removed and the
natural grade restored within six months of the date that the Division of Land
Resources has released the project.
5. Certificate of Completion
Upon completion of all work approved within the 401 Water Quality Certification
or applicable Buffer Rules, and any subsequent modifications, the applicant is
required to return the attached certificate of completion to the 401/Wetlands Unit,
North Carolina Division of Water Quality, 1650 Mail Service Center, Raleigh, NC,
27699-1650.
6. Lake Drawdown
Wildcat Lake shall be drawn down from the surface using a skimmer at a rate of
no more than one foot per twenty four hour period. The drawdown shall cease at
the moment that turbid water / sediments are picked up from the bottom of the
impoundment such that downstream water quality standards are not exceeded.
Any excavated sediments from behind the Wildcat Lake Dam shall be dewatered,
moved to high ground, and stabilized in place, such that no water quality
standards are contravened.
7. Outlet Protection
Outlet protection shall be designed in such a manner that discharges will not
aggrade nor degrade sediments, shall not result in downstream instability, and
shall not result in an unnatural widening of the stream. The emergency spillway
shall also be designed such that downstream stability will maintained when
passing storm events up to, and including the 25 year storm event.
8. Diffuse Flow (No Review)
All constructed stormwater conveyance outlets shall be directed and maintained
as diffuse flow at non-erosive velocities through protected stream buffers such
that it will not re-concentrate before discharging into a stream.
9. Buffer Establishment around Basins
Basins are considered by the DWQ as a modification of the existing shoreline
(the natural stream). As such, a 50-foot buffer that complies with the Guidelines
for Riparian Buffer Restoration Guidelines must be established around the
shoreline. You are required to establish a new buffer around the shoreline of the
Wildcat Lake Dam Repair
Page 4 of 3
December 15, 2006
basin for all areas where a buffer is lacking. Any and all associated upland
development (such as parking lots, buildings, etc.) and any new impervious
surfaces shall not be located within the newly established buffer or any existing
protected buffers.
10. Turbidity Standard
The turbidity standard of 50 NTUs (Nephelometric Turbidity Units) shall not be
exceeded as described in 15 A NCAC 2B. .0200. Appropriate sediment and
erosion control practices must be used to meet this standard.
11. Water Release Structures
The water release structure for this dam must be designed for mid-column
release during normal flows and during low flow conditions it must also provide
for low flow release to the downstream channel.
12. Deed Notifications
Deed notifications or similar mechanisms shall be placed on all retained
jurisdictional wetlands, waters and protective buffers in order to assure
compliance for future wetland, water and buffer impact. These mechanisms shall
be put in place prior to impacting any wetlands, waters and/or buffers approved
for impact under this Certification Approval and Authorization Certificate. A
sample deed notification can be downloaded from the 401/Wetlands Unit web
site at http://h2o.enr.state.nc.uslncwetiands. The text of the sample deed
notification may be modified as appropriate tQ suit to this project.
13. Minimum Release from Dams
Before any of the impacts approved in the Certification are conducted you must
submit, and obtain written approval by this Office for a minimum water release
plan. The plan must include a written explanation of the specific discharge rate and
mechanism to provide for each required release. The plan must also include any
design specifications, details and calculations to show that the release shall be
achieved in the given conditions. The plan shall also include monitoring that
ensures compliance. The plan and any associated facilities, once approved, must
be in place and implemented prior to the completion of the drawdown of the lake
and facilities started prior to the drawdown ceasing.
14. Notification of Construction
The applicant and/or authorized agent shall contact the DWQ Asheville Regional
Office in writing at the following address within 10 days of the commencement of
construction.
Wildcat Lake Dam Repair
Page 5 of 3
December 15, 2006
NC DENR - Division of Water Quality
2090 US Highway 70
Swannanoa, NC 28778
Violations of any condition herein set forth may result in revocation of this Certification
and may result in criminal and/or civil penalties. The authorization to proceed with your
proposed impacts or to conduct impacts to waters as depicted in your application and
as authorized by this Certification, shall expire upon expiration of the 404 or CAMA
Permit.
If you do not accept any of the conditions of this Certification (associated with the
approved wetland or stream impacts), you may ask for an adjudicatory hearing. You
must act within 60 days of the date that you receive this letter. To ask for a hearing,
send a written petition, which conforms to Chapter 150B of the North Carolina General
Statutes to the Office of Administrative Hearings, 6714 Mail Service Center, Raleigh,
N.C. 27699-6714. This certification and its conditions are final and binding unless you
ask for a hearing.
This letter completes the review of the Division of Water Quality under Section 401 of
the Clean Water Act. If you have any questions, please telephone Kevin Barnett in the
DWQ Asheville Regional Office at 828-296-4657.
Sincerely,
Alan W. Klimek, P.E., Director
Division of Water Quality
AW K/khb
Enclosures: GC 3494
Certificate of Completion
Guidelines for Riparian Buffer Restoration
cc: Dale E. Pennell, P.E.
McGill and Associates, P.A.
Post Office Box 2259
Asheville, NC 28802
USACE Asheville Regulatory Field Office
Cyndi Karoly, DWQ 401 /Wetlands Central Office
DLR Asheville Regional Office
Ron Linville, NC Wildlife Resources Commission
File Copy
Central Files
Filename: 06-1752.WildcatDamRepair.Approval
A,
3 y,
'vi
North Carolina Wildlife Resources Commission
Richard B. Hamilton, Executive Director
MEMORANDUM
TO: Amanda Jones, Permit Coordinator
Asheville Office, U.S. Army Corps of Engineers
Cyndi B. Karoly, Supervisor
401 Oversight and Express Permits Unit
NCDWQ Wetlands and Stormwater Branch
FROM: Ron Linville, Regional Coordinator
Habitat Conservation Program
DATE: November 16, 2006
ra°
1-n $ --
TV
jC IWY ..
1? e?n111;t4.
LF 11k pq
SUBJECT: Review of an application by Edgar Tufts-Memorial Association, Wildcat Lake
Dam Retrofit and Repair, DWQ N . 0061752, Wildcat Creek, Avery Count
The applicant is requesting a letter of concurrence from the North Carolina Wildlife Resources
Commission (NCWRC) to obtain a 404 permit from the U.S. Army Corps of Engineers. The
NCWRC has reviewed information provided by the applicant, and field biologists on our staff
are familiar with habitat values of the project area. These comments are provided in accordance
i
with provisions of the Clean Water Act of 1977 (33 U.S.C. 466 et. seq.) and the Fish and
Wildlife Coordination Act (48 Stat. 401, as amended; 16 U.S.C. 661-667d).
{
The project is to install an earthen dam over an existing and failing concrete dam, which will be
used as a core for the structure. The new dam will have a primary and emergency spillway as
well as a bottom lake drain. Impacts are indicated to be 128 linear feet of stream. Wild Brown
trout are known for waters in the area.
Based on the information provided by the applicant and our knowledge of the range of trout in
the project area, we do not believe this project will cause significant effects to waters supporting
trout providing the following conditions are followed:
Instream work and land disturbance within the 25-foot wide buffer zone are
prohibited during the brown and brook trout spawning season of October 15 through
Mailing Address: Division of Inland Fisheries - 1721 Mail Service Center - Raleigh, NC 27699-1721
i Telephone: [phone] - Fax: [phone]
Edgar Tufts Mem. Assoc. Dam -Page 2 -
November 16, 2006
April 15 to protect the egg and fry stages of trout from off-site sedimentation during
construction.
2. The new structure should include a cold water release (see attached) plus ensure re-
aeration of discharge waters to meet trout water standards for temperature and
dissolved oxygen.
3. A minimum base flow release should be provided that meets NC Division of Water
Resources requirements. In no event should downstream flows be diminished below
inflow rates during the life of the dam with the exception of initial impoundment
filling, downstream flows may be minimally reduced. At a minimum, the 7Q10 must
be provided during impoundment filling even though higher base flows are desirable
and appropriate to protect aquatic life.
4. Sediment and erosion control measures shall adhere to the design standards for
sensitive watersheds (15A NCAC 4B .0124).
5. Approvals for the dam's design and construction should be obtained from the NC
Division of Land Resources as appropriate.
6. If concrete will be used, work must be accomplished so that wet concrete does not
contact stream water.
7. If practicable, we recommend that the impoundment have a littoral shelf to provide
improved safety and aquatic vegetated edge habitats. Autochthonous plants are
recommended around the impoundment if feasible to provide wildlife habitats and to
reduce thermal impacts to waters (see attached example). High elevation plants will
be appropriate for Avery County. Species like silky dogwood, rhododendron, dog
hobble, red maple, silky willow, tag alder, black willow, sycamore, black walnut or
other native woody species may be appropriate.
Thank you for the opportunity to review and comment on this project. If you have any questions
regarding these comments, please contact me at 336/769-9453.
Attachments: Piedmont Stormwater Pond and Mine Planting Recommendations
Fisheries Management Fact Sheet 2003
E-copy: Kevin Barnett, DWQ-ARO
-- - Shawna Riddle, DLR-ARO
Edgar Tufts Mem. Assoc. Dam -Page 3 -
Piedmont Stormwater Pond and Mine Planting Recommendations
November 16, 2006
Instead of using the typical fescue grasses or exotic plant species, the following mixtures should be
considered for lower elevation stormwater ponds and mine sites:
Spring/Summer Mixture, May 1 Sept. 15
Fall/Winter Mixture, Sept. 15 - April 30
Browntop millet 201bs/a
Kobe lespedeza 20 lbs/a
Shrub lespedeza 1 lb/a
Switchgrass* 51b/a
Winter Wheat 1201bs/a
Kobe lespedeza 201bs/a
Shrub lespedeza 1 lb/a
Switchgrass* 5lb/ac
Add to fall or spring plantings: `Tioga' Deertongue (Panicum clandestinum) at a rate of 7 lbs. Pure Live
Seeds (PLS) per acre.
* When possible on slopes less than 3:1 use Switchgrass instead of lespedezas and on slopes greater than 3:1 use
Orchard Grass or Creeping Red Fescue. Other native species may be appropriate depending on soil slope and
region. Korean lespedeza may be appropriate in colder geophysical areas. We do not recommend Sericea lespedeza
and prefer not to use Korean or Kobe unless necessary as they are exotic. Native plants and warm season grasses
are preferred over exotic plants.
Add one of the following to the above mixture:
Creeping Red Fescue 51bs/acre
Ladino Clover** 5 lbs/acre
Atlantic Coastal Panic Grass 5 lbs/acre (PLS)
Alfalfa* * 5 lbs/acre (requires fertilizer containing Boron)
** Lime & fertilize disturbed areas according to NRCS soil test results and follow planting guidelines as appropriate
and necessary. Depending on elevation and region, other native species may be appropriate. Note that mowing
should be limited to late winter or early spring. Mowing should only occur as needed to prevent unwanted tree
growth on a 2-3 year schedule.
The provision of shade around impounded waters can significantly reduce thermal impacts. Trees and
shrubs (1 year bare root seedlings) should be planted randomly at a minimal rate of 100 trees per acre on
the top and upper portions of the structure and at a minimal rate of 150 per acre around the normal water
elevation and littoral shelf area. The following list of tree species may assist in providing habitat benefits:
Loblolly Pine* Red Cedar Black Gum American Holly Dogwood
Hickory Sumac White Oak Willow Oak Red Maple**
Viburnum Green Ash Ironwood Black Cherry Persimmon
Water Oak Spice Bush Willow (sp) Serviceberry Red Oak
Swamp Chestnut Silky Dogwood
Other species may be utilized depending on site requirements and native plant availability. Pines* should not
exceed 15% of the reforestation. No more than 20% of the tree species will be of a single species. An 80% success
rate is acceptable over five years. Large or fast growing trees like Sycamore and Maple** may not be appropriate
near detention facility dams. Note: Non-native plants included in this list are routinely considered beneficial and/or
agriculturally established non-natives. They have been included as they are readily available commercially and they
do not exhibit many of the negative attributes of other non-natives that tend to spread or inhibit native plant
propagation and survival.
Edgar Tufts Mem. Assoc. Dam -Page 4 - November 16, 2006
`/
Fisheries Management Fact Sheet 2003
What: Environmental Impacts Caused by Ponds. Ponds provide aesthetic benefits, water for crop irrigation and
livestock, as well as fishing opportunities and wildlife habitat. However, ponds can be detrimental to fish, wildlife,
and water quality if constructed improperly. Ponds that are created by damming streams, and ponds of any type that
continuously release water back into a stream can be especially harmful.
Where: Poorly designed ponds can impact aquatic life and water quality statewide, but the impacts are greatest
around ponds located in and near coldwater streams in the mountains and foothills.
When: Historically, ponds were built on farms to supply water for livestock and crop irrigation. In recent years, the
rate of pond construction has increased as more and more people move to the mountains and build ponds to improve
die appearance of their property or to provide fishing opportunities.
Why: There are two major problems that ponds can cause. First, a pond created by damming a stream impedes the
migration of many aquatic organisms along the stream, including fish, mussels, and amphibians. The second
problem is related to the release of warm water from ponds. Because impounded water warms more quickly than
moving water, water is considerably warmer in ponds than in free flowing streams. Furthermore, the warmest water
within a pond will be at the surface, while the coolest water will be found near the pond bottom. Within most
ponds, the water that flows out of the pond and back into adjacent streams is drawn off the surface. When this
warm surface water is released, water temperatures within the stream increase, harming trout, smallmouth bass, and
other species adapted to cooler water temperatures. While there can be thermal impacts below ponds that only
release water periodically during heavy rain events, the impacts will be most severe below ponds that constantly
release water.
How to build ponds without damming the stream channel: To ensure that the migration of aquatic organisms
within streams are not blocked when building a pond, consider locating new ponds away from streams and using
surface runoff, springs, or water pumped from wells as water sources. Ponds can also be filled by building them
adjacent to a stream and diverting or pumping a small portion of the stream water into the pond to fill it. Water
should only be diverted into the pond continuously while the pond is being filled Once the pond is filled, water
should only be diverted into the pond as needed to maintain water levels.
How to reduce the thermal impacts of pond outflows: Thermal impacts caused by ponds that continuously
release surface water into streams can be reduced in ponds that are equipped with a standpipe to regulate water
levels. The installation of a bottom drawoff device (see diagram on neat page) over the existing standpipe helps
reduce the temperature of water released by the pond by siphoning off the cooler water found near the pond bottom.
Furthermore, a bottom drawoff also helps prevent fish kills in ponds by removing the stagnant, low oxygen water
from the pond bottom. The drawoff pipe needs to be large enough in diameter so that the cross-sectional area of the
space between the two pipes is greater than the cross-sectional area of the drainpipe. The pipe needs to be long
enough to reach into the cooler/deeper waters of the pond, and should leave at least a couple feet of clearance above
the bottom to avoid future interference from sediment accumulation. The drawoff pipe should be constructed of a
relatively light but rigid material (aluminum is best). Heavy pipes are difficult to mount and put extra strain on the
standpipe that could eventually cause its failure. If the drawoff pipe material isn't sufficiently rigid it may collapse
under the suction pressure. Typically drawoff pipes are mounted by inserting two crossbars through the pipe 6-12
inches from the top end, then putting the drawoff pipe over the standpipe so that these crossbars rest on the top of
Edgar Tufts Mem. Assoc. Dam -Page 5 - November 16, 2006
the standpipe. Three bolts or pins can be inserted into the pipe several feet down from the top to serve as spacers
that will keep the drawoff pipe vertical and centered on the standpipe.
12
k
?y. .4.4. •y
:i
18"
Bottom water withdrawal devices do have their limitations. Ponds that are very shallow and/or small may not
benefit since the water temperatures near the bottom and at the surface will be more similar. Also. if the outflow
from a pond is going directly into a stream, then the water should be aerated by routing it to splash onto rocks or
other hard, jagged surfaces as it re-enters the stream.
More information concerning pond construction and management is found in the "Pond Management Guide-'
published by the N.C. Wildlife Resources Commission and the N.C. Agricultural Extension Service. This guide can
be obtained online at ???vw.n -%i ldlifc.or , or by calling 919 733-3633.
N.C. Wildlife Resources Commission Division of Inland Fisheries
F: . _r [phone].
Triage Check List
Date: 11/08/06 Project Name: Wildcat Lake Dam Repair
DWQ #:06-1752
A County: Avery
Kevin Barnett, Asheville Regional Office
To:
60-day Processing Time: 11/07/06 to 1/05/07
From: Cyndi Karoly Telephone: [phone]
The file attached is being forwarded to you for your evaluation.
Please call if you need assistance.
Stream length impacted
? Stream determination
Wetland determination and distance to blue-line surface waters on USFW topo maps
? Minimization/avoidance issues
? Buffer Rules (Meuse, Tar-Pamlico, Catawba, Randleman)
? Pond fill
Mitigation Ratios
? Ditching
? Are the stream and or wetland mitigation sites available and viable?
Check drawings for accuracy
Is the application consistent with pre-application meetings?
? Cumulative impact concern
Comments: As per our discussion regarding revision of the triage and delegation processes,
please review the attached file. Note that you are the first reviewer, so this file will need to be
reviewed for administrative as well as technical details. If you elect to place this project on hold,
please ask the applicant to provide your requested information to both the Central Office in
Raleigh as well as the Asheville Regional Office. As we discussed, this is an experimental, interim
procedure as we slowly transition to electronic applications. Please apprise me of any
complications you encounter, whether related to workload, processing times, or lack of a "second
reviewer" as the triage process in Central had previously provided. Also, if you think of ways to
improve this process, especially so that we can plan for the electronic applications, let me know.
Thanks!
McGidl ()LP - 1 152
- A S S O C I A T E S
'1, P,?}?NT
E?E:VED
November 3, 2006 R12@12 OWN
D
NOV 7 - 2006
Ms. Cyndi Karoly, 401 Unit Supervisor
401 Oversight and Express Permits Unit ait-,4o-c - WATER QUALITY
1650 Mail Service Center WEItMOSAMD5TORIAWATERBRANDi
Mail Service Center
Raleigh, NC 27699-1650
t,
RE: 404/401 Permit Application
Proposed Wildcat Lake Dam
Repair Plan
Avery County, North Carolina
Dear Ms. Karoly:
Please find enclosed the following items in support of the enclosed application for a
404/401 Permit for the subject property:
1. Seven sets of plans.
2. Seven copies of the completed Pre-Construction Notification Application form.
3. Seven copies of the site location map.
4. A check in the amount of $200 for this application.
The Edgar Tufts Memorial Association is preparing plans to repair the Wildcat Lake
Dam located in Avery County, south of the Town of Banner Elk. The current concrete dam is
experiencing cracking and spalling. The North Carolina Department of Environment and
Natural Resources Division of Land Quality (NCDENR DLQ) has requested that the dam be
repaired. Since the existing structure was constructed in 1933 and does not have a functioning
spillway, McGill Associates, P.A. has proposed a dam repair plan that would use the existing
concrete dam as a concrete core and build a earthen dam with a lake drain, cold water return and
primary and emergency spillway. The enclosed application covers the installation of 93 linear
feet of culvert in Wildcat Creek below the existing dam to allow for the building of a
downstream slope and installation of a new cold water return. This repair plan will not only
ensure the stability of the structure, but also bring the dam up to current standards.
E n g i n e e r i n g • P l a n n i n g • F i n a n c e
McGill Associates, P.A. • P.O. Box 2259, Asheville, NC 28802 • 55 Broad Street, Asheville, NC 28801
828-252-0575 • Fax: [phone]
Ms. Cyndi Karoly
November 3, 2006
Page 2 of 2
Please feel free to contact myself or Jennifer Ballard, P.E., of our office with any
questions or concerns.
Sincerely,
McGILL ASSOCIATES, P.A.
1"5DALE E. PENNELL, P.E., P.L.S.
Enclosures
cc: Mr. Murray White, Jr., Edgar Tufts Memorial Association
06129/letters/D WQ.doc
Office Use Only: Form Version March 05
USACE Action ID No. DWQ No. O Lo - 11 S Z
(1t any particular item is not applicable to this project, please enter "Not Applicable" or "N/A".)
! i 4q
ENT
1. Processing
RECEIVED
1. Check all of the approval(s) requested for this project:
® Section 404 Permit ? Riparian or Watershed Buffer Rules
? Section 10 Permit ? Isolated Wetland Permit from DWQ
® 401 Water Quality Certification ? Express 401 Water Quality Certification
2. Nationwide, Regional or General Permit Number(s) Requested: 3
3. If this notification is solely a courtesy copy because written approval for the 401 Certification
is not required, check here: ?
4. If payment into the North Carolina Ecosystem Enhancement Program (NCEEP) is proposed
for mitigation of impacts, attach the acceptance letter from NCEEP, complete section VIII,
and check here: ?
5. If your project is located in any of North Carolina's twenty coastal counties (listed on page
4), and the project is within a North Carolina Division of Coastal Management Area of
Environmental Concern (see the top of page 2 for further details), check here: ?
II. Applicant Information p MW P D
1. Owner/Applicant Information Nab 7 ? 2006
Name: Edgar Tufts Memorial Association
Mailing Address: P. O. Box 2196 h??y ?WATER QUALITY
High Point, North Carolina 27261 wEt WbsAn sTORMWA ,11
Telephone Number: [phone] Fax Number: [phone]
E-mail Address: [e-mail]
2. Agent/Consultant Information (A signed and dated copy of the Agent Authorization letter
must be attached if the Agent has signatory authority for the owner/applicant.)
Name: Murray M. White, Jr.
Company Affiliation: Edgar Tufts Memorial Association
Mailing Address: P. O. Box 2196
High Point, North Carolina 27261
,Telephone Number: [phone] Fax Number: [phone]
E-mail Address: [e-mail]
Updated 11/1/2005
Page 5 of 12
III. Project Information
Attach a vicinity map clearly showing the location of the property with respect to local
landmarks such as towns, rivers, and roads. Also provide a detailed site plan showing property
boundaries and development plans in relation to surrounding properties. Both the vicinity map
and site plan must include a scale and north arrow. The specific footprints of all buildings,
impervious surfaces, or other facilities must be included. If possible, the maps and plans should
include the appropriate USGS Topographic Quad Map and NRCS Soil Survey with the property
boundaries outlined. Plan drawings, or other maps may be included at the applicant's discretion,
j so long as the property is clearly defined. For administrative and distribution purposes, the
USACE requires information to be submitted on sheets no larger than 11 by 17-inch format;
j however, DWQ may accept paperwork of any size. DWQ prefers full-size construction
drawings rather than a sequential sheet version of the full-size plans. If full-size plans are
reduced to a small scale such that the final version is illegible, the applicant will be informed that
the project has been placed on hold until decipherable maps are provided.
1. Name of project: Wildcat Lake Dam Repair
2. T.I.P. Project Number or State Project Number (NCDOT Only):
3. Property Identification Number (Tax PIN): 184802951025
4. Location
County: Avery Nearest Town: Banner Elk
Subdivision name (include phase/lot number):
Directions to site (include road numbers/names, landmarks, etc.): Take US 184 south from
Banner Elk. Turn Right on Hickory Nut Gap Road. Wildcat Lake Dam is located on the left
after the Grandfather Home for Children.
5. Site coordinates (For linear projects, such as a road or utility line,
separately lists the coordinates for each crossing of a distinct waterbody.)
Decimal Degrees (6 digits minimum): ON
6. Property size (acres): 14.60 acres
7. Name of nearest receiving body of water: Wildcat Creek
8. River Basin: Watauga
(Note - this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http://h2o.enr.state.nc.us/admin/maps/.)
9. Describe the existing conditions on the site and general land use in the vicinity of the project
at the time of this application: Site is currently used as a recreational lake and the
surrounding area is generally woodlands. The Grandfather Home for Children is located
immediately downstream of the lake.
attach a sheet that
ow
Updated 11/1/2005
Page 6 of 12
10. Describe the overall project in detail, including the type of equipment to be used: Bulldozers,
loaders, dump trucks and excavators will be used to install the earthen dam and the primary
and emergency spillways.
11. Explain the purpose of the proposed work: The purpose of this work is to repair the existing
dam that is beginning to fail. A primary and emergency spillway will be installed as well as
a bottom lake drain. Instead of attempting to repair the existing concrete dam it will be
turned into the dam core. An earthen dam will then be constructed around the concrete core.
This will bring the dam up to current standards and ensure the functionality of the dam
IV. Prior Project History
If jurisdictional determinations and/or permits have been requested and/or obtained for this
project (including all prior phases of the same subdivision) in the past, please explain. Include
the USACE Action ID Number, DWQ Project Number, application date, and date permits and
certifications were issued or withdrawn. Provide photocopies of previously issued permits,
certifications or other useful information. Describe previously approved wetland, stream and
buffer impacts, along with associated mitigation (where applicable). If this is a NCDOT project,
list and describe permits issued for prior segments of the same T.I.P. project, along with
construction schedules. N/A
V. Future Project Plans
Are any future permit requests anticipated for this project? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application.
N/A
VI. Proposed Impacts to Waters of the United States/Waters of the State
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
wetlands, open water, and stream channels associated with the project. Each impact must be
listed separately in the tables below (e.g., culvert installation should be listed separately from
riprap dissipater pads). Be sure to indicate if an impact is temporary. All proposed impacts,
permanent and temporary, must be listed, and must be labeled and clearly identifiable on an
accompanying site plan. All wetlands and waters, and all streams (intermittent and perennial)
should be shown on a delineation map, whether or not impacts are proposed to these systems.
Wetland and stream evaluation and delineation forms should be included as appropriate.
Photographs may be included at the applicant's discretion. If this proposed impact is strictly for
wetland or stream mitigation, list and describe the impact in Section VIII below. If additional
space is needed for listing or description, please attach a separate sheet.
1. Provide a written description of the proposed impacts: The proposed primary and emergency
spillway will discharge into the Wildcat Creek streambed. The current discharge overtops
the dam. There will be temporary disturbance during the earthen dam and the two spillways
construction.
Updated 11/1/2005
Page 7 of 12
2. Individually list wetland impacts. Types of impacts include, but are not limited to
mechanized clearing, grading, fill, excavation, flooding, ditching/drainage, etc. For dams,
senarately list impacts due to both structure and flooding.
Wetland Impact
Site Number
(indicate on map)
Type of Impact Type of Wetland
(e.g., forested, marsh,
herbaceous, bog, etc.) Located within
100-year
(e es/no) Flos/no) Distance to
Nearest
Stream
(linear feet) Area of
Impact
(acres)
N/A

Total Wetland Impact (acres)
3. List the total acreage (estimated) of all existing wetlands on the property:
4. Individually list all intermittent and perennial stream impacts. Be sure to identify temporary
impacts. Stream impacts include, but are not limited to placement of fill or culverts, dam
construction, flooding, relocation, stabilization activities (e.g., cement walls, rip-rap, crib
walls, gabions, etc.), excavation, ditching/straightening, etc. If stream relocation is proposed,
plans and profiles showing the linear footprint for both the original and relocated streams
must be included. To calculate acreage- multinly length X width. then divide by 4; 560
Stream Impact
Perennial Average Impact Area of
Number Stream Name Type of Impact Intermittent?
? Stream Width Length Impact
(indicate on ma) Before Impact (linear feet) (acres)
1 Wildcat Creek Fill fo
r
earthen Perennial 5 93 0
011
d
an
r
.
2 Wildcat Creek Primary Spillway Perennial 5 93 0.011
3 Wildcat Creek Riprap Outlet Perennial 5 35 0
0004
Protection .

Total Stream Impact (by length and acreage) 128 0.011
5. Individually list all open water impacts (including lakes, ponds, estuaries, sounds, Atlantic
Ocean and any other water of the U.S.). Open water impacts include, but are not limited to
fill. excavation. dredging. flooding. drainage- bulkheads- etc_
Open Water Impact
Site Number
(indicate on ma) Name of Waterbody

(if applicable)
Type of Impact Type of Waterbody
(lake, pond, estuary, sound, bay,

ocean, etc.) Area of
Impact

(acres)
1 Wildcat Lake Fill Lake 0.20

Total Open Water Impact (acres) 0.20
Updated 11/1/2005
Page 8 of 12
6. List the cumulative impact to all Waters of the U.S. resulting from the project:
7. Isolated Waters
Do any isolated waters exist on the property? ? Yes ® No
Describe all impacts to isolated waters, and include the type of water (wetland or stream) and
the size of the proposed impact (acres or linear feet). Please note that this section only
applies to waters that have specifically been determined to be isolated by the USACE.
8. Pond Creation
If construction of a pond is proposed, associated wetland and stream impacts should be
included above in the wetland and stream impact sections. Also, the proposed pond should
be described here and illustrated on any maps included with this application.
Pond to be created in (check all that apply): ? uplands ? stream ? wetlands
Describe the method of construction (e.g., dam/embankment, excavation, installation of
draw-down valve or spillway, etc.):
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.):
Current land use in the vicinity of the pond:
Size of watershed draining to pond:
VII. Impact Justification (Avoidance and Minimization)
Expected pond surface area:
Specifically describe measures taken to avoid the proposed impacts. It may be useful to provide
information related to site constraints such as topography, building ordinances, accessibility, and
financial viability of the project. The applicant may attach drawings of alternative, lower-impact
site layouts, and explain why these design options were not feasible. Also discuss how impacts
were minimized once the desired site plan was developed. If applicable, discuss construction
techniques to be followed during construction to reduce impacts. Repairs to current concrete dam
were evaluated. Such repairs would be temporary and would not correct the issue of no existine
spillway or lake drain.
VIII. Mitigation
DWQ - In accordance with 15A NCAC 2H .0500, mitigation may be required by the NC
Division of Water Quality for projects involving greater than or equal to one acre of impacts to
freshwater wetlands or greater than or equal to 150 linear feet of total impacts to perennial
streams.
Stream Impact (acres): 0.016
Wetland Impact (acres): N/A
Open Water Impact (acres): 0.20
Total Impact to Waters of the U.S. (acres) 0.01
Total Stream Impact (linear feet): 128
Updated 11/1/2005
Page 9 of 12
USACE - In accordance with the Final Notice of Issuance and Modification of Nationwide
Permits, published in the Federal Register on January 15, 2002, mitigation will be required when
necessary to ensure that adverse effects to the aquatic environment are minimal. Factors
including size and type of proposed impact and function and relative value of the impacted
aquatic resource will be considered in determining acceptability of appropriate and practicable
mitigation as proposed. Examples of mitigation that may be appropriate and practicable include,
but are not limited to: reducing the size of the project; establishing and maintaining wetland
and/or upland vegetated buffers to protect open waters such as streams; and replacing losses of
aquatic resource functions and values by creating, restoring, enhancing, or preserving similar
functions and values, preferable in the same watershed.
If mitigation is required for this project, a copy of the mitigation plan must be attached in order
for USACE or DWQ to consider the application complete for processing. Any application
lacking a required mitigation plan or NCEEP concurrence shall be placed on hold as incomplete.
An applicant may also choose to review the current guidelines for stream restoration in DWQ's
Draft Technical Guide for Stream Work in North Carolina, available at
http://h2o.enr.state.nc.us/ncwetlands/strmgide.html.
Provide a brief description of the proposed mitigation plan. The description should provide
as much information as possible, including, but not limited to: site location (attach directions
and/or map, if offsite), affected stream and river basin, type and amount (acreage/linear feet)
of mitigation proposed (restoration, enhancement, creation, or preservation), a plan view,
preservation mechanism (e.g., deed restrictions, conservation easement, etc.), and a
description of the current site conditions and proposed method of construction. Please attach
a separate sheet if more space is needed.
N/A
2. Mitigation may also be made by payment into the North Carolina Ecosystem Enhancement
Program (NCEEP). Please note it is the applicant's responsibility to contact the NCEEP at
[phone] to determine availability, and written approval from the NCEEP indicating
that they are will to accept payment for the mitigation must be attached to this form. For
additional information regarding the application process for the NCEEP, check the NCEEP
website at http://h2o.enr.state.nc.us/wm/index.ht!E. If use of the NCEEP is proposed, please
check the appropriate box on page five and provide the following information:
Amount of stream mitigation requested (linear feet):
Amount of buffer mitigation requested (square feet):
Amount of Riparian wetland mitigation requested (acres):
Amount of Non-riparian wetland mitigation requested (acres):
Amount of Coastal wetland mitigation requested (acres):
Updated 11/1/2005
Page 10 of 12
IX. Environmental Documentation (required by DWQ)
1. Does the project involve an expenditure of public (federal/state/local) funds or the use of
public (federal/state) land? Yes ? No
2. If yes, does the project require preparation of an environmental document pursuant to the
requirements of the National or North Carolina Environmental Policy Act (NEPA/SEPA)?
Note: If you are not sure whether a NEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ? No ?
3. If yes, has the document review been finalized by the State Clearinghouse? If so, please
attach a copy of the NEPA or SEPA final approval letter. Yes ? No ?
X. Proposed Impacts on Riparian and Watershed Buffers (required by DWQ)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
1. Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Neuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 02B .0243 (Catawba) 15A NCAC
2B .0250 (Randleman Rules and Water Supply Buffer Requirements), or other (please
identify V Yes ? No
2. If "yes", identify the square feet and acreage of impact to each zone of the riparian buffers.
If buffer mitigation is required calculate the required amount of mitigation by applying the
buffer multipliers.
Zone* Impact
(square feet) Multiplier Required
Mitigation
1 3 (2 for Catawba)
2 1.5
Total
zone 1 extends out 3u feet perpendicular from the top of the near bank of channel; Zone 2 extends an
additional 20 feet from the edge of Zone 1.
3. If buffer mitigation is required, please discuss what type of mitigation is proposed (i.e.,
Donation of Property, Riparian Buffer Restoration / Enhancement, or Payment into the
Riparian Buffer Restoration Fund). Please attach all appropriate information as identified
within 15A NCAC 2B .0242 or .0244, or.0260. N/A
Updated 11/1/2005
Page 11 of 12
XI. Stormwater (required by DWQ)
Describe impervious acreage (existing and proposed) versus total acreage on the site. Discuss stormwater
controls proposed in order to protect surface waters and wetlands downstream from the property. If
percent impervious surface exceeds 20%, please provide calculations demonstrating total proposed
impervious level. There is no existing or proposed impervious acreage. Silt fence and a check dam will
be installed during the construction phase.
XII. Sewage Disposal (required by DWQ)
Clearly detail the ultimate treatment methods and disposition (non-discharge or discharge) of
wastewater generated from the proposed project, or available capacity of the subject facility.
N/A
XIII. Violations (required by DWQ)
Is this site in violation of DWQ Wetland Rules (15A NCAC 2H.0500) or any Buffer Rules?
Yes ? No
Is this an after-the-fact permit application? Yes ? No
XIV. Cumulative Impacts (required by DWQ)
Will this project (based on past and reasonably anticipated future impacts) result in additional
development, which could impact nearby downstream water quality? Yes ? No
If yes, please submit a qualitative or quantitative cumulative impact analysis in accordance with
the most recent North Carolina Division of Water Quality policy posted on our website at
http://h2o.enr.state.nc.us/ncwetlands. If no, please provide a short narrative description:
XV. Other Circumstances (Optional):
It is the applicant's responsibility to submit the application sufficiently in advance of desired
construction dates to allow processing time for these permits. However, an applicant may
choose to list constraints associated with construction or sequencing that may impose limits on
work schedules (e.g., draw-down schedules for lakes, dates associated with Endangered and
Threatened Species, accessibility problems, or other issues outside of the applicant's control).
SI)n Ioks-4
Applicant/Agent's Signature ? ) ate 1
(Agent's signature is valid only if an authorization letter from the applicant is provided.)
i
Updated 11/1/2005
Page 12 of 12

} McGill

AO C I A T

CONSULTING ENGINEERS
ASHEVILLE,NORTH CAROLINA

WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
DALE E. PENNELL, P.E.
MC GioI I
A S S O C I A T E S
Engineering* Planning* Finance
Post Office Box 2259
Asheville, North Carolina 28802
OCTOBER, 2006
06129

?Ci5064
°°a???paatei?s
to.
'?j? . 0(p
o ??-'' - tiQO6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
i
1
1
1
1
WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 1 Review of State Instructions
SECTION 2 Existing Conditions at Wildcat Lake Dam
SECTION 3 Design Storm Calculations and Proposed Spillway System
APPENDIX A Design Calculations
APPENDIX B Location Map
2006/02129/misc/TOC.doc
WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 1
REVIEW OF STATE INSTRUCTIONS
In letters from Mr. Mike Goodson and Ms. Janet Boyer, PE of the North Carolina Department of
Environment and Natural Resources, Land Quality Section dated December 28, 2004 and June
30, 2006 respectively, three specific areas of concern with the Wildcat Lake Dam were
identified. These areas are as follows:
1. Cracks and spalling on the face of the dam. One crack of major concern is the one that
extends from the top of the dam down to the bottom drain. Continue to monitor the
cracks near the left and right abutments and center of the dam.
2.1 Seepage present at the bottom left of the dam.
3. An updated emergency action plan (EAP) is required for this dam.
In order to respond to the State's request, the owner of the dam, The Edgar Tufts Memorial
Association, retained the services of McGill Associates to prepare the dam's repair plan.
2006/06129/mi sc/Section l .doc

WILDCAT LAKE DAM
' PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 2
EXISTING CONDITIONS AT WILDCAT LAKE DAM
i
Wildcat Lake Dam is located in Avery County, off of Hickory Nut Gap Road, south of Banner
Elk. The lake is privately owned, by the Edgar Tufts Memorial Association, and is currently
used for recreation for several facilities, including the Grandfather Home for Children.
The surface area of the lake is approximately 509,650 square feet, or 11.7 acres, and is at an
elevation of 3751 feet above sea level. The watershed area draining to the lake is approximately
372 acres, as determined from the USGS quad map "Elk Park", having a maximum elevation of
4680 feet. The watershed is made up of single-family residential properties, vacation homes,
farmland, and undisturbed forest and mountain land. Wildcat Creek drains this watershed,
passing through the lake. A location map is enclosed in Appendix B.
The existing outlet for the lake is in the form of a 15" ductile iron pipe on the eastern end of the
dam. The elevation of the invert of this pipe is 3728. This pipe continues to plug and currently a
2 PVC pipe is stuck in the DIP to help this drain work. The only other means of flow control is
the overflow over the concrete dam. This generally occurs on the western side of the dam. The
15" DIP discharges on an embankment near the dam. The drainage then flows to a pool along
the toe of the dam where the water drains to the original streambed.
The current dam was constructed in 1933 to provide hydroelectric power to the area. There is
extensive cracking and spalling of the concrete. Also, the existing dam does not have a bottom
drain nor is there an effective primary or emergency spillway. The only means for water to
effectively leave the lake is to overtop the dam as the 15" DIP drain clogs frequently.
2006/06129/misc/Section1doc

WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 3
I' DESIGN STORM CALCULATIONS AND PROPOSED SPILLWAY SYSTEM
DESIGN STORM CALCULATIONS
The design storm for this project is the hundred year storm. Calculations are shown in Appendix
A. The rational method determined that the hundred year flow is 425.6 CFS while the SCS
method determined that the flow is 275 CFS. Therefore, the flow estimated by the rational
method was used. A base flow of 2.9 CFS was determined by the current outflow from the
lake's siphons. Therefore, a total design storm of 428.5 CFS was used. The time of
concentration, also assumed to be the time of peak flow, was determined to be 18 minutes, as
shown in Appendix A.
PROPOSED SPILLWAY SYSTEM
In order to properly size a spillway system, the temporary reservoir storage within the lake at
Wildcat Lake Dam was determined to account for its effect on the sizing of the spillway. The
storage volume used in the spillway calculations was determined by measuring the surface area
at the normal water level (NWL) elevation and at the water level elevation when the water begins
to flow through the emergency spillway and then calculating the volume based on the difference
in elevation between the two water levels. The normal water level is three (3) feet below the
dam crest, so the high water level was set at two (2) feet above the normal water level, leaving
one (1) foot of freeboard for safety. The storage amount was thus calculated to be 520,100 cubic
feet (CF). Using this volume along with the time of peak flow, the design flow out of the lake
(Q-out) was determined to be 188 CFS. The calculations are shown in Appendix A.
The most effective spillway for this dam is a standard riser/barrel structure with a lined
emergency channel. A 72" riser and 36" barrel, with 2-feet of head, will be used. This system is
capable of handling 160 CFS. The difference in the riser/barrel capacity (160 CFS) and the Q-
out (188 CFS) became the basis for the lined emergency channel design. A concrete lined
emergency channel was designed, using a 2-foot width. The calculations for this option are
shown in Appendix A. Installation of the riser and barrel will require a breach of the dam, so the
PVC pipe siphons will be used to regulate flow from the lake and prevent sedimentation to the
receiving stream during construction. The riser will have a concrete anti-flotation block and
combination trash rack/cold water return. The existing concrete dam will be used as a concrete
Wildcat Lake Dam
Section 3
Page 2
core. The 36" barrel will be bored through the existing concrete dam and sealed with watertight
mastic.
The dam's downstream slope will be constructed at a 2:1 slope since this area is located in a tight
valley surrounded by bedrock. The emergency spillway will be constructed next to the dam fill
slope on undisturbed ground.
2006/06129/misc/Section1doc
APPENDIX A
McGill
ASSOCIATES
Engineering* Planning • Finance
Post Office Box 2259
Asheville, North Carolina 28802
06129

Project: Wildcat Dam
Project Number: 06129
Description: Runoff Calculations
Calculated By: JJB Checked By: DP
Date: 10/9/2006
' Site is near Banner Elk, NC.
Drainage Area = 372 acres
Runoff Calculations (Rational Method)
Runoff Coefficient C er Table 8.03a

Cdrives, wanks &roofs = 17.96 acres X 0.8 = 14.37
CsoD = 2.00 acres X 0.3 = 0.60
Cgrass= 90.02 acres X 0.3 = 27.01
Cwoodiands = 262.02 acres X 0.15 = 39.30
Total 81.28

Cadjusted = 81.281 / 372.001 = 0.22
Q=aci
a = area = 372 acres See attached U.S.G.S. Map)
c = runoff coefficient= 0.22
i = rainfall intensity, based on time of concentration and year of the storm
i Ito = [L /H]/128 H = 4680-3720 = 960 feet
L = 7675 feet
to = [3180 /766] /128 = 17.0562 minutes= 18 minutes
i from Figure 8.03f @ 18 minutes

i2 = 2.5 in/hr i25 = 4.0 in/hr
i5 = 3.0 in/hr iso = 4.4 in/hr
i1o = 3.5 in/hr iloo = 5.2 in/hr

Q2 = 372 * 0.22 * 2.5 = 204.6 CFS
as = 372 * 0.22 * 3.0 = 245.5 US
Q10 = 372 * 0.22 * 3.5 = 286.4 CFS
025 = 372 * 0.22 * 4.0 = 327.4 CFS
Qso = 372 * 0.221 * 4.41 = 360.1 US
Q100 = 372 * 0.221 * 5.21 = 425.6 CFS
1
1
1
1
Runoff Calculations (SCS Method)
Area = 372 acres
Hydraulic length = 7675 feet
Average Slope = H/L = 12.5%
CN
CNdrlves, walks koofs = 17.96 acres X 98 = 1760.08
CNsoll= 2.00 acres X 89 = 178.00
Cgrass= 90.02 acres X 61 = 5491.22
Cwoodlands = 262.02 acres X 55 = 14411.10
Total 21840.40
CNadjusted = 21840.40 1/ 372.001 = 58.71
CN = 60.00 Soil Group B, Ad'. above - See Figure 8.03b
Rainfall Amount (Fiaures 8.03h-m)
Rainfall Depth Figure 8.03c)
2 year, 1 day = 3 inches 0.33 inches
5 year, 1 day = 4 inches 0.76 inches
10 year, 1 day= 5 inches 1.30 inches
25 year, 1 day= 5.5 inches 1.61 inches
50 year, 1 day= 6 inches 1.92 inches
100 year, 1 day = 71- inches 2.60 inches
Equivalent Drainage Area = L = 209ao.6
7675 =209a' .6
a= 405.7 acres equivalent drainage area (Figure 9.03n)
Peak Drainage = 160 CFS/inch runoff (Figure 8.03q)
Adjusted Peak Discharge =
Peak Discharge * Rainfall Depth * (actual acreage/eq. area) * Slope Factor * Ponding Factor
Actual, Acreage/Equivalent Area = 0.9
Slope Factor = 0.925
Pnnriinn Fartnr• Ariiimfori 0
0.64 2 year, 1 day = 28.66
0.65 5 ear, 1 day = 67.04
0.67 10 year, 1 day = 118.20
0.71 25 year, 1 day = 155.12
0.75 50 year 1 day = 195.41
0.78 100 year, 1 day= 275.20
USE 425.6 CFS from Rational Method for Design Calculations
Base flow is equal to the amount of water through three of the 3" PVC siphons
currently going over the dam. This is equal to 0.95 CFS per pipe or a total
base flow of 2.9 CFS.
USE A TOTAL FLOW OF 428.5 CFS FOR DESIGN CALCULATIONS FOR THE 100 YEAR STORM.
2 of 2
Table 8.03a
d Use C Land Use C
Value of Runoff Coefficient [Ne1i
(C) for Rational Formula iness: Lawns:
owntown areas 0.70.0.95 Sandy soil, flat, 2% 0.05-0.10
ghborhood areas 0
.50-0.70 Sandy soil; ave., 2-7% 0.10-0.15
Sandy soil, steep, 7% 0.15-0.20
idential: Heavy soil, flat, 2% 0.13-0.17
ngle-family areas 0.30-0.50 Heavy soil, ave., 2-7% 0.18-0.22
ti units, detached 0.40-0.60 Heavy soil, steep, 7% 0.25-0.35
Multi units, attached 0.60-0.75
Suburban 0.25-0.40 Agricultural land:
Bare packed soil -
Industrial: Smooth 0.30.0.6 O,(o
Light areas 0.50-0.80 Rough 0. 5Q
Heavy areas 0.60-0.90 Cultivated rows
Heavy soil no crop 0.30-0.60
Parks, cemeteries 0.10-0.25 Heavy soil with crop 0.20-0.50
Sandy soil no crop 0.20-0.40
Playgrounds 0.20-0.35 Sandy soil with crop 0.10-0.25
Pasture
Railroad yard areas 0.20-0.40 Heavy soil 5-0.45 O, 3
Sandy soil 0.05-0-.25
Unimproved areas 0.10-0.30 Woodlands _0.25 D. IS
Streets:
Asphalt 0.70-0.95
Concrete 0.80-0.95
Brick 0.70-0.85
Drives and walks 0.75-0.85
' Roofs 0.75-0.85 D,
1.
j NOTE: The designer must use judgment to select the appropriate C value
' within the range for the appropriate land use. Generally, larger areas with
permeable soils, flat slopes, and dense vegetation should have lowest C
values. Smaller areas with slowly permeable soils, steep slopes, and
sparse vegetation should be assigned. highest C values.
' Source:_American Society of Civil Engineers
i
! The overland flow portion of flow time may be determined from Figure 8.03a.
The flow time (in minutes) in the channel can be estimated by calculating the
average velocity in feet per minute and dividing the length (in feet) by the
average velocity.
Step 4. Determine the rainfall intensity, frequency, and duration (Figures 8.03b
through 8.03g-source: North Carolina State Highway Commission; Jan.
1973). Select the chart for the locality closest to your location. Enter the
"duration" axis of the chart with the calculated time of concentration, Tc. Move
vertically until you intersect the curve of the appropriate design storm, then
' move horizontally to read the rainfall intensity factor, i, in inches per hour.
Step S. Determine peak discharge, Q (ft3/sec), by multiplying the previously
determined factors using the rational formula (Sample Problem 8.03a).
i
8.03.? ? -
Appendices
0
L
i ._
a?
L
U
C
C
C
C
co
C
tY
Figure 8.03f Rainfall intensity duration curves-Asheville.
b-
0
0
L
N
m
L
U
C
.N
C
d
.S O.E
m O.E
c
0.4
0.2
0.1
5 10 20
Minutes
r' Figure 8.03g Rainfall intensity duration curves-Charlotte.
Duration
40 60 2 3 4 6 8 12 18 24
Duration Hours
f
8.03.7
??jj - V Ll
MYnutes Hours
1 ,
SCS Peak Discharge Method
The peak discharge method of calculating runoff was developed by the USDA
Soil Conservation Service and is contained in SCS Technical Release No. 55
(TR-55) entitled Urban Hydrology for Small Watersheds, Second Ed.; June
1986. This method of runoff calculation yields a total runoff volume as well as
a peak discharge. Use of the SCS method is illustrated in Sample Problem 8.03b
and in Chapter 7, Sample Erosion and Sedimentation Control Plan.
Step 1. Measure the drainage area (in acres); the hydraulic length (distance
from most remote point to design point, in feet); and the average slope (percent)
of the watershed.
Step 2. Calculate a curve number, ON, for the drainage area.
The curve number, ON, is an empirical value, which establishes a relationship
between rainfall and runoff based upon characteristics. of the drainage area.
Table 8.03b contains ON values for different land uses, cover conditions, and .
hydrologic soil groups. Hydrologic group assignments for most common soils
in North Carolina are given in Appendix 8.01. If the soil name is not known,
judge the soils based on the group description below:
• Soil Group A-Represents soil having a low runoff potential due to high
infiltration rates. These soils consist primarily of deep, well-drained sands
nnrt arnvele ?----_-.-
• Soil Group B-Represents soils having a moderately low runoff potential
due to moderate infiltration rates. These soils consist primarily of moder-
ately deep to deep, moderately well-drained to well-drained soils with
moderately fine to moderately coarse textures.
Soil Group - i s aving a mo erately high runoff poten-
tial due to slow infiltration rates. These soils consist primarily of soils in
which a layer exists near the surface that impedes the downward move-
ment of water, or soils with moderately fine to fine texture.
• Soil Group D-Represents soils having a high runoff potential due to
very slow infiltration rates. These soils consist primarily of soils with high
water tables, soils with a claypan or clay layer at or near the surface, and
shallow soils over nearly impervious parent material.
I
If the watershed is homogeneous (i.e., uniform land use and soils) the ON value
can be determined directly from Table 8.03b. Curve numbers fornonhomogene-
ous watersheds may be determined by dividing the watershed into homogeneous
subareas and computing a weighted average.
Step 3. Select design storm and determine runoff depth and volume for erosion
and sediment control using the 10-yr, 24-hr storm.
a. Determine rainfall amount, in inches, from Figures 8.03h through 8.03m
for the selected design storm. (The design storm is based on an SCS Type
II, 24-hr rainfall distribution.)

?R
8.03.8
Rev. 12193
v
Table 8.03b
Runoff Curve Numbers (CN)
Hyd i is Soil Group
A ? C D
Land Use/Cover
Cultivated land
without conservation 72 81 88 91
with conservation 62 71 78 81
Pasture land
poor condition 68 79 86 89
fair condition 49 69 79 84
good condition 39 `61`1 74 80

Meadow
good condition 30 58 71 78
Wood or forest land
Thin stand - poor cover, no mulch 45 66 77 83
Good stand - good cover 25 X55 70 77
Open spaces, lawns, parks, golf courses, cemeteries, etc.
good condition:
grass cover on 75%
or more of the area 39 61 74 80
fair condition:
grass cover on 50
to 75% of the area 49 69 79 84
Commercial and business
areas (85% impervious) 89 92 94 F 95
Industrial districts
(72% impervious] 81 88 91 93
Residential:' Development completed and vegetation establis hed
Average lot size Average % Impervious
1/8 acre or less 65 77 85 90 92
1/4 acre 38 61 75 83 87
1 /3 acre 30 57 72 81 86
1 /2 acre 25 54 70 80 85
1 acre 20 51 68 79 84
2 acre 15 47 66 77 81
Paved parking lots, roofs,
driveways, etc. 98 98 98 98
Streets and roads
paved with curbs and
storm sewers 98 98 98 98
gravel 76 85 89 91
dirt 72 82 87 89
Newly graded area 81 89 93 95
Residential: Development underway and no vegetation
Lot sizes of 1/4 acre 88 93 95 97
Lot sizes of 1/2 acre 85 91 94 96
Lot sizes of 1 acre 82 90 93 95
Lot sizes of 2 acres 81 89 92 94
'Curve numbers are computed assuming the runoff from the house and driveway is directed toward the street.
source: USDA-SCS
8.03.10

Rev. IV93

LA LM
Q

C/ • h\

)
a

I ?
0 ?d
a ! `1• z` S =

r 01 Ln\
C 1 Y .. b11=
?. \ T
i \ ??7
-
.

- a
6 ro J Ln ?•? /
'T
•
=
,? Y
„

N Q
IL M
?
I
I ?r cF
l
i
?y1 _ • J 2
I• 0
Z n f

EC-E. V!
O
y' ; O r 1
t ? - ?

u1

Ln
` n \1

Figure 8.03h 2-year 1 da y precipitation (inches)

1
r4 v
Appendices
8.03.11

Li

10
.o
Ll q?
Sri
n
c
r
1 PP. C ? iiJ
??O
G%?o 4 s; ? O^
L, pJ% i = J
~'Q
s?

S
-
Icz J r o` ;/y? L R i d

_.? i •

C p
1 = I• II-=Mb?1?•?•
T
Z ` ,•^' ?? Lf;
\
'
. .
/
1p1 `

L J 1 i
o
'
-'
cc Q
LL Q: I
_
j- o I
ar 1 S
T a Q I_ - 1
a =
OC ?_•? ?r '?
c .. -. c rE (weW??? Li

rh y• 1. ; ` '? - v
z ?•
I
i ?
? ?T
1
•
i c
I0%
M .-.. ;
• ?
"C' L
l
?
+

v 1 VC
Figure 8.0315
-year
1 day precipitation
(inches) `
1

c 1
Ln

8.03.12
Appendices
10
J
`JP',` p' h `? i •?
J
Ij' pl
1 r +• t? \ V
lclo?
= s W t
1 '?JP 1 -
Ill
N 1• w?M11R0 ? \ "•1
10
10
N U.
r
)
ID Ln
o 1 °
o a \ N
' 1 F o ° I= I 0 Ln
ixx
`•?j o % 337
i 'IT
p R
a• t
A
?r
%
t
z'
%
= 1 Y 0
Figure 8.03j 10-year 1 day precipitation (inches)
? .o
8.03.13
D
Li
00 00
11 I•J "? '\
F ?Y i , r Ln
00
..,j
o W
j / z ?• ? ?= a Zap
1 r ` _ ? ? t I : Ma
?,-1• _ .mac' r ? ? ;
10
°
.C CL
Q Li ° I• ??'\• i \ 2i/
C n Ln Jay, a l r •?
> J -
•p Q ; n I I r?? i1 ` '? ?p
Rs Z ? I r' ? ? ? ?f i
N ° Ul z I= ?• 4 1
o \
??-:?.• c EC.L MOUPG
140
r1 ?? J
ti? r 3 ? I
- •? o = r13A
L 31j1
17& ,
' :1 I n
s ?
Ln? 8 a
Figure 8.03k 25-year 1 day precipitation (inches) CO
' a n
i I
8.03.14
f?
1
Appendices
1 -
0
a
r ?
ar, i r '?
&
00
.

. C ? tai I _ V

cc:

_ ; f r o r ,?•
u

n
te
n,,
o ~• ? ? \
N I. ?

2
.
?. Ca

a Ln

.? I Y

10
•
co
.a•. a ? UaG??
.? o I HECkIF
r.
•
•
CI
LO N
`'
T v ?'
r_•1f. Lq
10

= Own 7??1p
i

CO

% 0%
m 1

_ ?,0.
\
r Figure 8.031 50-year 1 day precipitation (inches)
\

?r

I
r
r`
fa
8.03.15
0
a
8
r a.

o Q

U ?
a J
J
a
n U_
Z

a Q
?
0 0
I o 4V / _ ( o
ap J7• cu? 1i\ : c`? c
,y-n lam. / 0 I i
01
I _ : ?as? c 1 \ /?
I o
s I ci' . •?
o
r
10
,? ? wn3,31j
CC)
`O ?? " \• J t O?
\ z
%
? T
Figure 8.03m 100-year 1 day precipitation (inches)

8.03.16
i
O,
f?
6
0

C"
101
0
PEAK RATES OF
DISCHARGE FOR
SMALL WATERSHEDS
ON A STEEP SLOPE,
24-HOUR STORM,
TYPE II
DISTRIBUTION
i
i
i
0
C
DRAINAGE AREA, ACRES wv Jw
Figure 8.03q Discharge vs equivalent drainage area for average watershed slopes 8 - 50%.

cvw l u
8.03.20
Appendices
Table 8.03d
Slope Adjustment Factors
Slope
' 10' . 20 50 100 200
(percent) acres acres acres acres acres
Flat 0.1 0,49 0.47 0.44 0.43 0.42
0.2 0.61 0.59 0.56 0.55 0.54
0.3 0.69 0.67 0.65 0.64 0.63
0.4 0.76 0.74 0.72 0.71 0.70
0.5 0.82 0.80 0.78 0.77 0.77
0.7 0.90 0.89 0.88 0.87 0,87
1.0 1.00 1.00 1.00 1.00 1.00
1.5 1.13 1.14 1.14 1.15 1.16
Moderate 3 0.93 0.92 0.91 0.90 0.90
4 1.00 1.00 ` 1,00 1,00 1.00
5 1.04. 1.05 1.07 1.08 1.08
6 1.07 1.10 1,12 1.14 1.15
7 1.09 1.13 1.18 1.21 1.22
Steep 8 0.92 0.88 0.84 0.81 0.80
9 0.94 0.90 0.86 0,84 0.83
10 0.96 0.92 0.88. 0.87 0.86
11 0.96 0.94 0.91 0.90 0.89
21 X12
13 0.97
0.97 0.95
0.97 0.93
0.95 0.92
0.94 0 914
0.94
14 0.98 0.98 0.97 0.96- 0.96
15 0.99 0.99 0.99 0.98 0.98
16 1.00 1.00 1.00 1.00 1.00
20 1:03 1.04 1.05 1.06 1.07
25 1.06 1.08 1.12 1.14 1.15
30 1.09 1.11 1.14 1.17 1.20
40 1.12 1.16 1,20 1.24 1.29
50. 1.17 1.21 1.25 1.29 1.34
source: USDA-SCS

8.03.23

Table 8.03e
Adjustment Factors for Ponding and Swampy Areas
Adjustment factors where pondina and swampy areas occur at the design point.
Ratio of drainage Percentage of
are
and a to ponding
s ponding and Storm fre uenc ears
wampy area -swampy area 1 --5-0- 1
n
500

6
200 0.2 0.92 0.94 0.95
' 0.96 0.97 0.98

a
100 .5 .86 .87 .88 .90 .92 .93

50 1.0 .80 .81 .83 .85 .87 .89

(
. 2.0
2.5 .74
.69 .75
70 .76
72 .79
75 .82
78 .86
8
?
3.3
.64 .
.65 .
.67 .
.71 .
.75 .
2
.78

15 5.0
6
7 .59
57 .61 .63 .67 .71 .75

3
10 . . .58 .60 .64 .67 .71

5 10.0 .53 .54 .56 .60 .63 .68
20.0 .48 .49 .51 .55 .59 .64
Adjustment factors where ponding and swampy areas are spread throughout the
watershed or occur in central parts of the watershed
Ratio of drainage Percentage of
area to ponding ponding and Storm fre uency (years)
and swampy area swampy area _
z 5 _
lp 25 0 1
5 00
500
200 0.2 0.94 0.95 0.96 0.97 0.98 0.99

100 .5 .88 .89 .90 .91 .92 .94

50 1.0 .83 .84 .86 .87 .88 .90
2.0 .78 .79 .81 .83 .85 87
40 2.5 .73 .74 .76 .78 .81 .
84
30 3.3 .69 .70 .71 .74 .77 .
81
20 5.0 .65 .66 .68 .72 .75 .
78
15 6.7 .62 .63 .65 .69 .72 .
75
10 10.0 .58 .59 .61 .65 .68 .
71
5 20.0 .53 .54 .56 .60 .63 .
68
4 25.0 .50 .51 .53 .57 .61 .
.66
Adjustment factors where ponding and swampy areas are located only in upper
reaches of the watershed.
Ratio of drainage Percentage of
area to ponding ponding and Storm freq uent (years)
and swampy area swampy area 2 5 10 25 50 100

500 0.2 0.96 0.97 0.98 0.98 0.99 0
99
200 .5 .93 .94 .94 .95 .
.96 .
97
100 1.0 .90 .91 .92 .93 .94 .
95
50 2.0 .87 .88 .88 .90 .91 .
93
40 2.5 .85 .85 .86 .88 .89 .
.91
30 3.3 .82 .83 .84 .86 .88 89
20 5.0 .80 .81 .82 .84 .86 .
88
15 6.7 .78 .79 .80 .82 .84 .
.86
10 10.0 .77 .77 .78 .80 .82 84
5 20.0 .74 .75 .76 .78 .80 .
.82

8.03.24
Project: Wildcat Lake Dam
Project Number: 06129
Description: Spillway Calculations
Calculated B : JJB Checked B DP
Date: 10/9/2006
Storage Available in Pond Riser + 1 Foot :
Pond surface area @ 3751 = 509,652 SF = 11.70 acres
Crest of dam ® Elev 3754.5; Maximum High water level @ 0100 = 3753.0
Pool at to riser @ 3751 + 1 foot at elevation 3752 = 530,561 SF = 12.18 acres
Volume of storage = ((pool+pond surface)/2) ' (pool elev. - pond surface
=J 520,106 CF
Determine effect of available storage on Qom,„ vs Q.
Q;,, = 0100 + Base Flow= 425.61 + 2.9 = 428.5 CFS
Tp = ? = 18 minutes (see runoff calcs) " 60 sec/min = 1080 sec
Storage = (Q;,, - Qo„t) " Tp " 2 (safety factor)
520,106 = ( 428.51- QO,t) ' 1080 sec 1-2
low = 187.7 CFS
Combined capacity of riser/barrel (principal spillway) and emergency spillway = 187.7 CFS
(Note: Storage is calculated to 1 foot over riser; max pond elevation is 2.0 feet over top riser. This
adds additional storage as safety factor, not including 1.5 foot of freeboard above maximum pond elevation.)
Design principal spillway (ps) and emergency spillway (es) to handle 187.7 CFS
at 2 feet over top riser (leaving 1.5 foot freeboard above maximum pond elevation.)
"ax Pond Elev = 3753.0
Determine Flow in Riser/Barrel:
Determine flow through barrel at orifice flow (Q=cdA4(2gh))
Determine flow through riser at orifice flow (Q=cdA4(2gh))
Determine flow into riser at weir flow (0x„,LH3'2)
The least of the three is the allowable flow in the riser/barrel.
To elev. of riser 3751 = 32.2
Elev. at freeboard 3753 cd = 0.6 (coeff . of discharge)
bottom of riser 3720 c. = 3.0
end of barrel 3716
Dia of riser 72 inches L = 18.8 feet
riser pipe area 28.27 SF H = 2 feet
Dia of barrel 36 inches hbrre1= 31.50 feet
Barrel pipe area 7.07 SF
Height of riser 31 feet
Centerline of barrel 3721.5
1 of 2
Barrel orifice
IQ= 191.0 CFS

Riser orifice
IQ= 192.5 CFS

Riser weir
I Q= 160.0 CFS

The riser calculations are the limitin factor.
Qps = 160.0 CFS
Qo„ t = 187.7 CFS
Qo„ t - Qps = Qes

Qe$ = 27.6 CFS
Emergency Spillway (Concrete Channel)
D
W i
use:
Q = 27.6 CFS
N = 0.015
S = 0.392
Z = 2 :1
W= 2
ID= 0.35
-oncrete (Table 8.05b)
Thus, the combined Qout = 187.7 CFS
2of2

1
1
Project: Wildcat Lake Dam
Project Number: 06129
Description: Concrete Flotation Block
Calculated By: JJB Checked B DP
Date: 10/10/2006
3751
31'
4.5' 4
1 3720
I 8" Drain = 2.1 SF

36" Barrel = 12.6 SF
72" Riser = 18.9 SF
1 Water Displaced:
8" Drain = 2.1 *4.5 = 9.41 CF
36" Barrel = 12.6 *6 = 75.42 CF
72" Riser = 18.9 *31 = 584.35 CF
Total 669.18 CF

Water Displaced =Water Displaced * 7.48 al/CF
Water Displaced = 5005.47 gallons *2.0 Safe Factor
= 10010.94 gallons
Wei ht Displaced = Water displaced ( allons *8.33 lb/gal
Weight Displaced= 83391.13 ounds
' Concrete = 150 ound/CF
Volume of Concrete Required = 555.9 CF
i
11' 72" Riser
' 5'6" 36" Barrel
1 s ''
11'

Pipe Volumes
Less 8" = 1.57
Less 36"= 9.43
Less 72"= 47.13
58.12
5.5'Hi h*11.'*11'= 665.5 CF
665.5 - 58.121= 607.38 CF Concrete Provided
Vs. 555.90 CF Conc. Required Oka
1 of 1
Project: Wildcat Lake Dam
Project Number: 06129
Description: Rip Rap Outlet Protection Calculations
Calculated B : JJB Checked B : DEP
Date: 10/11/2006
Pipe diameter = 36 inches
Pipe Maximum Flow= 160 cfs
d50 Ri rap Size = 1.7 ft = 20.4 inches from Figure 8.06b
d50 Ri rap Size = 24 inches (sizes of rip rap available
Max stone dia dmax = 1.5 X d50 = 3 ft
Outlet stone thickness = 1.5 X dmax 4.5 ft = 54 inches
Appendices
LI
'Po -----IT

N
tom'
1
a
0
LO
Z. u
20,
luu _ 500
lUUV
Discharge (ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (T. < 0.5 diameter).

Rev. 1:x93
8.06.3
Emergency Spillway
Worksheet for Trapezoidal Channel
Project Description
Project File p:\2006\06129\misc\spillway.fm2
Worksheet Emergency Spillway
Flow Element Trapezoidal Channel
Method Manning's Formula
Solve For Channel Depth

Input Data
Mannings Coefficient 0.013
1
Channel Slope 0.392000 ft/ft
Left Side Slope 2.000000 H : V
Right Side Slope 2.000000 H : V
'
Bottom Width 2.00 ft
Discharge 27.60 cfs

Results
Depth 0.35 ft
' Flow Area 0.94 ft2
Wetted Perimeter 3.56 ft
Top Width 3.39 ft
' Critical Depth 1.23 ft
Critical Slope 0.002964 ft/ft
Velocity 29.43 ft/s
Velocity Head 13.46 ft
Specific Energy 13.81 ft
Froude Number 9.87
' Flow is supercritical.
Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 [phone]
FlowMaster v5.13
Page 1 of 1
APPENDIX B
McGiR
ASSOCIATES
Engineering* Planning • Finance
Post Office Box 2259
Asheville, North Carolina 28802
06129
i
wad
raw•, -
.,
ficr .L'1??e Chi-
* / , 'I 4rf
4 l
X14
II >
rr !!,i
EAR----?
-- f
$ r-
41
WILDCAT LAKE
. ¦ ¦ ¦ DRAINAGE AREA
•
AVERY COUNTY, NORTH CAROLINA
I
ti I
1 \
Office Use Only: Form Version March 05
USACE Action ID No. DWQ No. 06 - I 15 P?
(it any particular item is not applicable to this project, please enter "Not Applicable" or "N/A".)
1. Processing
IL,
1. Check all of the approval(s) requested for this project:
® Section 404 Permit ? Riparian or Watershed Buffer Rules
? Section 10 Permit ? Isolated Wetland Permit from DWQ
® 401 Water Quality Certification ? Express 401 Water Quality Certification
2. Nationwide, Regional or General Permit Number(s) Requested: 3
3. If this notification is solely a courtesy copy because written approval for the 401 Certification
is not required, check here: ?
4. If payment into the North Carolina Ecosystem Enhancement Program (NCEEP) is proposed
for mitigation of impacts, attach the acceptance letter from NCEEP, complete section VIII,
and check here: ?
i
5. If your project is located in any of North Carolina's twenty coastal counties (listed on page
4), and the project is within a North Carolina Division of Coastal Management Area of
Environmental Concern (see the top of page 2 for further details), check here: ?
IL [ Applicant Information D L9 ?
1. Owner/Applicant Information NOV 7 2006
Name: Edgar Tufts Memorial Association
Mailing Address: P. O. Box 2196 eENR - WATER QLjA,
High Point, North Carolina 27261 L'NUWATER
Telephone Number: [phone] Fax Number: [phone]
E-mail Address: [e-mail]
2. Agent/Consultant Information (A signed and dated copy of the Agent Authorization letter
must be attached if the Agent has signatory authority for the owner/applicant.)
Name: Murray M. White, Jr.
Company Affiliation: Edgar Tufts Memorial Association
Mailing Address: P. O. Box 2196
High Point, North Carolina 27261
.Telephone Number: _(336) 889-4747 Fax Number: [phone]
E-mail Address:[e-mail]
Updated 111112.005
I
Page 5 of 12
III. Project Information
4
i
5.
Attach a vicinity map clearly showing the location of the property with respect to local
landmarks such as towns, rivers, and roads. Also provide a detailed site plan showing property
boundaries and development plans in relation to surrounding properties. Both the vicinity map
and site plan must include a scale and north arrow. The specific footprints of all buildings,
impervious surfaces, or other facilities must be included. If possible, the maps and plans should
include the appropriate USGS Topographic Quad Map and NRCS Soil Survey with the property
boundaries outlined. Plan drawings, or other maps may be included at the applicant's discretion,
so long as the property is clearly defined. For administrative and distribution purposes, the
USACE requires information to be submitted on sheets no larger than 11 by 17-inch format;
however, DWQ may accept paperwork of any size. DWQ prefers full-size construction
drawings rather than a sequential sheet version of the full-size plans. If full-size plans are
reduced to a small scale such that the final version is illegible, the applicant will be informed that
the project has been placed on hold until decipherable maps are provided.
1. Name of project: Wildcat Lake Dam Repair
2. T.I.P. Project Number or State Project Number (NCDOT Only):
3. Property Identification Number (Tax PIN): 184802951025
Location
County: Avery Nearest Town: Banner Elk
Subdivision name (include phase/lot number):
Directions to site (include road numbers/names, landmarks, etc.): Take US 184 south from
Banner Elk. Turn Right on Hickory Nut Gap Road. Wildcat Lake Dam is located on the left
after the Grandfather Home for Children.
Site coordinates (For linear projects, such as a road or utility line,
separately lists the coordinates for each crossing of a distinct waterbody.)
Decimal Degrees (6 digits minimum): ON
6. Property size (acres): 14.60 acres
7. Name of nearest receiving body of water: Wildcat Creek
8. River Basin: Watauga
(Note - this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http://h2o.enr.state.nc.us/admin/maps/.)
9. Describe the existing conditions on the site and general land use in the vicinity of the project
at the time of this application: Site is currently used as a recreational lake and the
surrounding area is generally woodlands. The Grandfather Home for Children is located
immediately downstream of the lake.
attach a sheet that
OW
Updated 11/1/2005
Page 6 of 12
10. Describe the overall project in detail, including the type of equipment to be used: Bulldozers,
loaders, dump trucks and excavators will be used to install the earthen dam and the primary
and emergency spillways.
11. Explain the purpose of the proposed work: The purpose of this work is to repair the existing
dam that is beginning to fail. A primary and emergency spillway will be installed as well as
a bottom lake drain. Instead of attempting to repair the existing concrete dam it will be
turned into the dam core. An earthen dam will then be constructed around the concrete core
This will bring the dam up to current standards and ensure the functionality of the dam
IV. Prior Project History
If jurisdictional determinations and/or permits have been requested and/or obtained for this
project (including all prior phases of the same subdivision) in the past, please explain. Include
the USACE Action ID Number, DWQ Project Number, application date, and date permits and
certifications were issued or withdrawn. Provide photocopies of previously issued permits,
certifications or other useful information. Describe previously approved wetland, stream and
buffer impacts, along with associated mitigation (where applicable). If this is a NCDOT project,
list and describe permits issued for prior segments of the same T.I.P. project, along with
construction schedules. N/A
V. Future Project Plans
Are any future permit requests anticipated for this project? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application.
N/A
VI. Proposed Impacts to Waters of the United States/Waters of the State
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
wetlands, open water, and stream channels associated with the project. Each impact must be
listed separately in the tables below (e.g., culvert installation should be listed separately from
riprap dissipater pads). Be sure to indicate if an impact is temporary. All proposed impacts,
permanent and temporary, must be listed, and must be labeled and clearly identifiable on an
accompanying site plan. All wetlands and waters, and all streams (intermittent and perennial)
should be shown on a delineation map, whether or not impacts are proposed to these systems.
Wetland and stream evaluation and delineation forms should be included as appropriate.
Photographs may be included at the applicant's discretion. If this proposed impact is strictly for
wetland or stream mitigation, list and describe the impact in Section VIII below. If additional
space is needed for listing or description, please attach a separate sheet.
1. Provide a written description of the proposed impacts: The proposed primary and emergency
spillway will discharge into the Wildcat Creek streambed. The current discharge overtops
the dam. There will be temporary disturbance during the earthen dam and the two spillways
construction.
Updated 11/1/2005
Page 7 of 12
2. Individually list wetland impacts. Types of impacts include, but are not limited to
mechanized clearing, grading, fill, excavation, flooding, ditching/drainage, etc. For dams,
separately list impacts due to both structure and flooding.
Wetland Impact
Site Number
(indicate on map)
Type of Impact Type of Wetland
(e.g., forested, marsh,
herbaceous, bog, etc.) Located within
100-year
Floodplain
( es/no) Distance to
Nearest
Stream
(linear feet) Area of
Impact
(acres)
N/A

Total Wetland Impact (acres)
3. List the total acreage (estimated) of all existing wetlands on the property:
4. Individually list all intermittent and perennial stream impacts. Be sure to identify temporary
impacts. Stream impacts include, but are not limited to placement of fill or culverts, dam
construction, flooding, relocation, stabilization activities (e.g., cement walls, rip-rap, crib
walls, gabions, etc.), excavation, ditching/straightening, etc. If stream relocation is proposed,
plans and profiles showing the linear footprint for both the original and relocated streams
must be included. To calculate acreage, multit)ly length X width. then divide by 43.560.
Stream Impact Perennial or Average Impact Area of
Number Stream Name Type of Impact Intermittent? Stream Width Length Impact
(indicate on ma) Before Impact (linear feet) (acres)
1 Wildcat Creek Fill for earthen Perennial 5 93 0
011
E dam .
2 Wildcat Creek Primary Spillway Perennial 5 93 0.011
3 Wildcat Creek RP Outlet Perennial 5 35 0
0004
Prot rotection .

Total Stream Impact (by length and acreage) 128 0.011
5. Individually list all open water impacts (including lakes, ponds, estuaries, sounds, Atlantic
Ocean and any other water of the U.S.). Open water impacts include, but are not limited to
fill, excavation, dredging, flooding, drainage, bulkheads, etc.
Open Water Impact
Site Number

(indicate on ma) Name
(if applicable) Waterbody
plicable)
Type of Impact Type of Waterbody

(lake, pond, estuary, sound, bay,
ocean, etc.) Area of

Impact
(acres)
I Wildcat Lake Fill Lake 0.20

Total Open Water Impact (acres) 0.20
Updated 11/1/2005
Page 8 of 12
6. List the cumulative impact to all Waters of the U.S. resulting from the project:
Stream Impact (acres): 0.016
Wetland Impact (acres): N/A
Open Water Impact (acres): 0.20
Total Impact to Waters of the U.S. (acres) 0.01
Total Stream Impact (linear feet): 128
7. Isolated Waters
Do any isolated waters exist on the property? ? Yes ® No
Describe all impacts to isolated waters, and include the type of water (wetland or stream) and
the size of the proposed impact (acres or linear feet). Please note that this section only
applies to waters that have specifically been determined to be isolated by the USACE.
8. Pond Creation
If construction of a pond is proposed, associated wetland and stream impacts should be
included above in the wetland and stream impact sections. Also, the proposed pond should
be described here and illustrated on any maps included with this application.
Pond to be created in (check all that apply): ? uplands ? stream ? wetlands
Describe the method of construction (e.g., dam/embankment, excavation, installation of
draw-down valve or spillway, etc.):
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.):
Current land use in the vicinity of the pond:
Size of watershed draining to pond: Expected pond surface area:
VII. Impact Justification (Avoidance and Minimization)
Specifically describe measures taken to avoid the proposed impacts. It may be useful to provide
information related to site constraints such as topography, building ordinances, accessibility, and
financial viability of the project. The applicant may attach drawings of alternative, lower-impact
site layouts, and explain why these design options were not feasible. Also discuss how impacts
were minimized once the desired site plan was developed. If applicable, discuss construction
techniques to be followed during construction to reduce impacts. Repairs to current concrete dam
were evaluated. Such repairs would be temporary and would not correct the issue of no existing
spillway or lake drain.
VIII. Mitigation
DWQ - In accordance with 15A NCAC 2H .0500, mitigation may be required by the NC
Division of Water Quality for projects involving greater than or equal to one acre of impacts to
freshwater wetlands or greater than or equal to 150 linear feet of total impacts to perennial
streams.
Updated 11/1/2005
Page 9 of 12
USAGE - In accordance with the Final Notice of Issuance and Modification of Nationwide
Permits, published in the Federal Register on January 15, 2002, mitigation will be required when
necessary to ensure that adverse effects to the aquatic environment are minimal. Factors
including size and type of proposed impact and function and relative value of the impacted
aquatic resource will be considered in determining acceptability of appropriate and practicable
mitigation as proposed. Examples of mitigation that may be appropriate and practicable include,
but are not limited to: reducing the size of the project; establishing and maintaining wetland
and/or upland vegetated buffers to protect open waters such as streams; and replacing losses of
aquatic resource functions and values by creating, restoring, enhancing, or preserving similar
functions and values, preferable in the same watershed.
If mitigation is required for this project, a copy of the mitigation plan must be attached in order
for USACE or DWQ to consider the application complete for processing. Any application
lacking a required mitigation plan or NCEEP concurrence shall be placed on hold as incomplete.
An applicant may also choose to review the current guidelines for stream restoration in DWQ's
Draft Technical Guide for Stream Work in North Carolina, available at
http://h2o.enr.state.nc.us/newetiands/stimgide.html.
Provide a brief description of the proposed mitigation plan. The description should provide
as much information as possible, including, but not limited to: site location (attach directions
and/or map, if offsite), affected stream and river basin, type and amount (acreage/linear feet)
of mitigation proposed (restoration, enhancement, creation, or preservation), a plan view,
preservation mechanism (e.g., deed restrictions, conservation easement, etc.), and a
description of the current site conditions and proposed method of construction. Please attach
a separate sheet if more space is needed.
N/A
2. Mitigation may also be made by payment into the North Carolina Ecosystem Enhancement
Program (NCEEP). Please note it is the applicant's responsibility to contact the NCEEP at
[phone] to determine availability, and written approval from the NCEEP indicating
that they are will to accept payment for the mitigation must be attached to this form. For
additional information regarding the application process for the NCEEP, check the NCEEP
website at http:Hh2o.enr.state.nc.us/wm/index.htm. If use of the NCEEP is proposed, please
check the appropriate box on page five and provide the following information:
Amount of stream mitigation requested (linear feet):
Amount of buffer mitigation requested (square feet):
Amount of Riparian wetland mitigation requested (acres):
Amount of Non-riparian wetland mitigation requested (acres):
Amount of Coastal wetland mitigation requested (acres):
i
Updated 11/1/2005
Page 10 of 12
IX. Environmental Documentation (required by DWQ)
1. Does the project involve an expenditure of public (federal/state/local) funds or the use of
public (federal/state) land? Yes ? No
2. If yes, does the project require preparation of an environmental document pursuant to the
requirements of the National or North Carolina Environmental Policy Act (NEPA/SEPA)?
Note: If you are not sure whether a NEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ? No ?
3. If yes, has the document review been finalized by the State Clearinghouse? If so, please
attach a copy of the NEPA or SEPA final approval letter. Yes ? No ?
X. Proposed Impacts on Riparian and Watershed Buffers (required by DWQ)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
1. Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Neuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 02B .0243 (Catawba) 15A NCAC
2B .0250 (Randleman Rules and Water Supply Buffer Requirements), or other (please
identify V Yes ? No
2.
If "yes", identify the square feet and acreage of impact to each zone of the riparian buffers.
If buffer mitigation is required calculate the required amount of mitigation by applying the
buffer multipliers.
Zone* Impact
(square feet)
Multiplier Required
Mitigation
1 3 (2 for Catawba)
2 1.5
Total
Lone 1 extends out 3U feet perpendicular from the top of the near bank of channel; Zone 2 extends an
additional 20 feet from the edge of Zone 1.
3. If buffer mitigation is required, please discuss what type of mitigation is proposed (i.e.,
Donation of Property, Riparian Buffer Restoration / Enhancement, or Payment into the
Riparian Buffer Restoration Fund). Please attach all appropriate information as identified
within 15A NCAC 2B .0242 or.0244, or.0260. N/A
Updated 11/1/2005
Page 11 of 12
XI. Stormwater (required by DWQ)
Describe impervious acreage (existing and proposed) versus total acreage on the site. Discuss stormwater
controls proposed in order to protect surface waters and wetlands downstream from the property. If
percent impervious surface exceeds 20%, please provide calculations demonstrating total proposed
impervious level. There is no existing or proposed impervious acreage. Silt fence and a check dam will
be installed during the construction phase.
XII. Sewage Disposal (required by DWQ)
Clearly detail the ultimate treatment methods and disposition (non-discharge or discharge) of
wastewater generated from the proposed project, or available capacity of the subject facility.
N/A
XIII. Violations (required by DWQ)
Is this site in violation of DWQ Wetland Rules (15A NCAC 2H.0500) or any Buffer Rules?
Yes ? No
Is this an after-the-fact permit application? Yes ? No
XIV. Cumulative Impacts (required by DWQ)
Will this project (based on past and reasonably anticipated future impacts) result in additional
development, which could impact nearby downstream water quality? Yes ? No
If yes, please submit a qualitative or quantitative cumulative impact analysis in accordance with
the most recent North Carolina Division of Water Quality policy posted on our website at
http://h2o.enr.state.nc.us/ncwetlands. If no, please provide a short narrative description:
XV. Other Circumstances (Optional):
It is the applicant's responsibility to submit the application sufficiently in advance of desired
construction dates to allow processing time for these permits. However, an applicant may
choose to list constraints associated with construction or sequencing that may impose limits on
work schedules (e.g., draw-down schedules for lakes, dates associated with Endangered and
Threatened Species, accessibility problems, or other issues outside of the applicant's control).
J O,o
Applicant/Agent's Signature ate
(Agent's signature is valid only if an authorization letter from the applicant is provided.)
Updated 11/1/2005
Page 12 of 12
ou
WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
DALE E. PENNELL, P.E.
4????,,tt?s° Ott
t
E McG- ill;
ASSOCIATES A3 wA1
Engineering* Planning* Finance z
COGCD
Post Office Box 2259
Asheville, North Carolina 28802 °°P?A?aaiecta`
10
OCTOBER, 2006
06129

WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 1 Review of State Instructions
SECTION 2 Existing Conditions at Wildcat Lake Dam
SECTION 3 Design Storm Calculations and Proposed Spillway System
APPENDIX A Design Calculations
APPENDIX B Location Map
2006/02129/misc/TOC.doc
WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
1
SECTION 1
' REVIEW OF STATE INSTRUCTIONS
r
In letters from Mr. Mike Goodson and Ms. Janet Boyer, PE of the North Carolina Department of
Environment and Natural Resources, Land Quality Section dated December 28, 2004 and June
30, 2006 respectively, three specific areas of concern with the Wildcat Lake Dam were
identified. These areas are as follows:
r
1. Cracks and spalling on the face of the dam. One crack of major concern is the one that
' extends from the top of the dam down to the bottom drain. Continue to monitor the
cracks near the left and right abutments and center of the dam.
' 2. Seepage present at the bottom left of the dam.
3. An updated emergency action plan (EAP) is required for this dam.
r
In order to respond to the State's request, the owner of the dam, The Edgar Tufts Memorial
Association, retained the services of McGill Associates to prepare the dam's repair plan.
1
r
1
r 2006/06129/misc/Sectionl.doc
1
r

WILDCAT LAKE DAM
' PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
' SECTION 2
EXISTING CONDITIONS AT WILDCAT LAKE DAM
Wildcat Lake Dam is located in Avery County, off of Hickory Nut Gap Road, south of Banner
Elk. The lake is privately owned, by the Edgar Tufts Memorial Association, and is currently
used for recreation for several facilities, including the Grandfather Home for Children.
The surface area of the lake is approximately 509,650 square feet, or 11.7 acres, and is at an
' elevation of 3751 feet above sea level. The watershed area draining to the lake is approximately
372 acres, as determined from the USGS quad map "Elk Park", having a maximum elevation of
4680 feet. The watershed is made up of single-family residential properties, vacation homes,
farmland, and undisturbed forest and mountain land. Wildcat Creek drains this watershed,
passing through the lake. A location map is enclosed in Appendix B.
The existing outlet for the lake is in the form of a 15" ductile iron pipe on the eastern end of the
dam. The elevation of the invert of this pipe is 3728. This pipe continues to plug and currently a
2" PVC pipe is stuck in the DIP to help this drain work. The only other means of flow control is
' the overflow over the concrete dam. This generally occurs on the western side of the dam. The
15" DIP discharges on an embankment near the dam. The drainage then flows to a pool along
the toe of the dam where the water drains to the original streambed.
i
The current dam was constructed in 1933 to provide hydroelectric power to the area. There is
extensive cracking and spalling of the concrete. Also, the existing dam does not have a bottom
' drain nor is there an effective primary or emergency spillway. The only means for water to
effectively leave the lake is to overtop the dam as the 15" DIP drain clogs frequently.
i
i

1 2006/06129/misc/Section2.doc

WILDCAT LAKE DAM
PROPOSED REPAIR PLAN
AVERY COUNTY, NORTH CAROLINA
SECTION 3
DESIGN STORM CALCULATIONS AND PROPOSED SPILLWAY SYSTEM
DESIGN STORM CALCULATIONS
The design storm for this project is the hundred year storm. Calculations are shown in Appendix
A. The rational method determined that the hundred year flow is 425.6 CFS while the SCS
method determined that the flow is 275 CFS. Therefore, the flow estimated by the rational
method was used. A base flow of 2.9 CFS was determined by the current outflow from the,
lake's siphons. Therefore, a total design storm of 428.5 CFS was used. The time of
concentration, also assumed to be the time of peak flow, was determined to be 18 minutes, as
shown in Appendix A.
PROPOSED SPILLWAY SYSTEM
In order to properly size a spillway system, the temporary reservoir storage within the lake at
Wildcat Lake Dam was determined to account for its effect on the sizing of the spillway. The
storage volume used in the spillway calculations was determined by measuring the surface area
at the normal water level (NWL) elevation and at the water level elevation when the water begins
to flow through the emergency spillway and then calculating the volume based on the difference
in elevation between the two water levels. The normal water level is three (3) feet below the
dam crest, so the high water level was set at two (2) feet above the normal water level, leaving
one (1) foot of freeboard for safety. The storage amount was thus calculated to be 520,100 cubic
feet (CF). Using this volume along with the time of peak flow, the design flow out of the lake
(Q-out) was determined to be 188 CFS. The calculations are shown in Appendix A.
The most effective spillway for this dam is a standard riser/barrel structure with a lined
emergency channel. A 72" riser and 36" barrel, with 2-feet of head, will be used. This system is
capable of handling 160 CFS. The difference in the riser/barrel capacity (160 CFS) and the Q-
out (188 CFS) became the basis for the lined emergency channel design. A concrete lined
emergency channel was designed, using a 2-foot width. The calculations for this option are
shown in Appendix A. Installation of the riser and barrel will require a breach of the dam, so the
PVC pipe siphons will be used to regulate flow from the lake and prevent sedimentation to the
receiving stream during construction. The riser will have a concrete anti-flotation block and
combination trash rack/cold water return. The existing concrete dam will be used as a concrete

Wildcat Lake Dam
Section 3
Page 2
core. The 36" barrel will be bored through the existing concrete dam and sealed with watertight
mastic.
The dam's downstream slope will be constructed at a 2:1 slope since this area is located in a tight
valley surrounded by bedrock. The emergency spillway will be constructed next to the dam fill
slope on undisturbed ground.
2006/06129/misc/Section1doc
APPENDIX A
f
McGill
ASSOCIATE S
Engineering* Planning • Finance
Post Office Box 2259
Asheville, North Carolina 28802
06129

Project: Wildcat Dam
Project Number: 06129
Description: Runoff Calculations
Calculated B JJB Checked By: I DP
Date: 10/9/2006
' Site is near Banner Elk, NC.
Drainage Area = 372 acres
Runoff Calculations (Rational Method)
Runoff Coefficient C er Table 8.03a

Cdrives, walks &roofs = 17.96 acres X 0.8 = 14.37
Csoii = 2.00 acres X 0.3 = 0.60
Cgrass = 90.02 acres X 0.3 = 27.01
Cwoodiands = 262.02 acres X 0.15 F 39.30
Total 81.28

Cadjusted = 81.28 / 372.001 = 0.22
Q I ac!

a = area = 372 acres See attached U.S.G.S. Ma
c = runoff coefficient = 0.22
i = rainfall intensity, based on time of concentration and year of the storm
' to _ [L /H] /128 H = 4680-3720 = 960 feet
L = 7675 feet
' Itc _ [31803/766]0-3 /128 = 17.0562 minutes = 18 minutes
i from Figure 8.03f @ 18 minutes

i2 = 2.5 in/hr i25 = 4.0 in/hr
i5 = 3.0 in/hr i5o = 4.4 in/hr
i,o = 3.5 in/hr i1oo = 5.2 in/hr

Qz = 372 * 0.22 * 2.5 = 204.6 CFS
Q5 = 372 * 0.22 * 3.0 = 245.5 CFS
Q10 = 372 * 0.22 * 3.5 = 286.4 CFS
025 = 372 * 0.22 * 4.0. = 327.4 CFS
Q50 = 372 * 0.221 - 4.4 = 360.1 CFS
Q1oo = 372 * 0.22 * 5.21 = 425.6 CFS
1 of 2
r
I
Runoff Calculations SCS Method
II
Area = 372 acres
Hydraulic length = 7675 feet
Average Slope = H/L = 12.5%
CN

CNdnves, walks &roofs = 17.96 acres X 98 = 1760.08
CNso;, = 2.00 acres X 89 = 178.00
Cgrass = 90.02 acres X 61 = 5491.22
Cwoodiands = 262.02 acres X 55 = 14411.10
Total 21840.40

'
Rainfall Amount Figures 8.03h-m Rainfall Depth Fi ure 8.03c)

CNad]usted= 21840.401 / 372.001 = 5$.71
CN = 60.00 Soil Group B, Ad'. above -See Figure 8.03b
2 year, 1 day 3 inches 0.33 inches
5 year, 1 day = 4 inches 0.76 inches
10 year, 1 day= 5 inches 1.30 inches
25i ear, 1 day= 5.5 inches 1.61 inches
50 year, 1 day = 6 inches 1.92 inches
100 year, 1 day = 7 inches -7 -2-6-07 1 nches
t Equivalent Drainage Area = L = 209aos
7675 = 209ao.s
a = 405.7 acres equivalent drainage area (Figure 9.03n)
' Peak Drainage = .160 CFSAnch runoff (Figure 8.03q)
Adjusted Peak Discharge =
' Peak Discharge * Rainfall Depth * (actual acreage/eq. area) * Slope Factor * Ponding Factor
Actual Acreage/Equivalent Area = 0.9
Slope Factor = 0.925
' Pondin Factor: Adjusted Q

0.64 2 year, 1 day = 28.66
0.65 5 year, 1 day = 67.04
0.67 10 year, 1 day= 118.20
0.71 25 year, 1 day = 155.12
0.75 50 year, 1 day = 195.41
0.78 100 year, 1 day= 275.20
USE 425.6 CFS from Rational Method for Design Calculations
Base flow is equal to the amount of water through three of the 3" PVC siphons
' currently going over the dam. This is equal to 0.95 CFS per pipe or a total
base flow of 2.9 CFS.
' USE A TOTAL FLOW OF 428.5 CFS FOR DESIGN CALCULATIONS FOR THE 100 YEAR STORM.
2of2
1 o
1 .
Table 8.03a
Value of Runoff Coefficient
C Land Use C
1 (C) for Rational Formula : Lawns:
n areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10
rhood areas 0.50-0.70 Sandy soil; ave
2-7% 0
1
F

' .,
.
0-0.15
Sandy soil, steep, 7% 0.15-0.20
Residential:
l: Heavy soil, flat
2% 0
13-0
17
,
.
.
mily areas 0.30-0.50 Heavy soil, ave., 2-7% 0.18-0.22
ts, detached 0.40-0.60 Heavy soil
stee
7% 0
25
0
,
p,
.
-
.35
t s, attached 0.60-0.75
1 Suburban 0.25-0.40 Agricultural land:
Bare packed soil
Industrial: Smooth 0
6 C, 6
30
0
.
-
.
Light areas 0.50-0.80 Rough 0. 50,
Heavy areas 0.60-0.90 Cultivated rows
Heavy soil no crop 0.30-0.60
Parks, cemeteries 0.10-0.25 Heavy soil with crop 0.20-0.50

1 Sandy soil no crop 0.20-0.40
Playgrounds 0.20-0.35 Sandy soil with crop 0.10-0.25
Pasture
Railroad yard areas 0.20-0.40 Heavy soil 5-0.45

1 Sandy soil 0.05-0-25
Unimproved areas 0.10-0.30 Woodlands _0.25 D, (Jr
Streets:
Asphalt 0.70-0.95
Concrete 0.80-0.95
'
1 Brick 0.70-0.85
Drives and walks 0
75-0
85
.
.
0,5
1 Roofs 0.75-0.85
l
NOTE: The designer must use judgment to select the appropriate value
within the range for the appropriate land use. Generally, larger rger areas with
permeable soils, flat slopes, and dense vegetation should have lowest C
values. Smaller areas with slowly permeable soils, steep slopes, and
sparse vegetation should be assigned. highest C values.
1 Source; American Society of Civil Engineers
1 The overland flow portion of flow time may be determined from Figure 8.03a
.
The flow time (in minutes in the channel can
be estimated b calculating
by the
average velocity in feet per minute and dividing
P the length
feet
(in b the
) by
1 average velocity.
Step 4. Determine the rainfall intensity, frequency, and duration (Figures 8.03b
through 8.03g-source: North Carolina State Highway Commission; Jan.
19

i 73). Select the chart for the locality closest to your location. Enter the
"duration" axis of the chart with the calculated time me of concentration, Te. Move
vertically until you intersect the curve of the appropriate design storm, then

1 move horizontally to read the rainfall intensity factor, i, in inches per hour.
Step S. Determine peak discharge, O (ft3/sec), by multiplying the previously
determined factors using the rational formula (Sample Problem 8.03a).
N
1 8.03.2
Appendices
0
r
m
r
U
G
a
C
C
C
fC
C
ca
I Figure 8.03f Rainfall intensity duration curves-Asheville.
is
7n
0
r
N
m
r
U
C
a
C
41
_S 01
ro O.E
C
0.4
0.2
0.1
Duration
5 10 20 40 60 2 3 4 6 8 12 18 24
' Minutes Hours
Duration
r' Figure 8.03g Rainfall intensity duration curves-Charlotte.
E
,'
8.03.7
-- v v iG io L9 '
MYnutes Hours

SCS Peak Discharge Method
The peak discharge method of calculating runoff was developed by the USDA
Soil Conservation Service and is contained in SCS Technical Release No. 55
(TR-55) entitled Urban Hydrology for Small Watersheds, Second Ed.; June
1986. This method of runoff calculation yields a total runoff volume as well as
a peak discharge. Use of the SCS method is illustrated in Sample Problem 8.03b
and in Chapter 7, Sample Erosion and Sedimentation Control Plan.

Step 1. Measure the drainage area On acres); the hydraulic length (distance
from most remote point to design point, in feet); and the average slope (percent)
' of the watershed.
Step 2. Calculate a curve number, CN, for the drainage area.
The curve number, CN, is an empirical value, which establishes a relationship
between rainfall and runoff based upon characteristics. of the drainage area.
Table 8.03b contains CN values for different land uses, cover conditions, and .
hydrologic soil groups. Hydrologic group assignments for most common soils
' in North Carolina are given in Appendix 8.01. If the soil name is not known,
judge the soils based on the group description below:
• Soil Group A-Represents soil having a low runoff potential due to high
infiltration rates. These soils consist primarily of deep, well-drained sands
and Rra v -- y
tely low runoff potential
Soil Group B-Represents soils
•
r
due [o moderate infiltration ratessist primarily of moder-
.
_
deep to deep, moderately well-drained soils with
ately
M
moderately fine to moderately c
hi
h runoff
oten-
i s ratel
amo
Soil G
y
g
p
roup -
•
tial due to slow infiltration rates. These so ils consist primarily of soils in
which a layer exists near the surface that impedes the downward move-
ment of water, or soils with moderately fine to fine texture.
Soil Group D-Represents soils having a high runoff potential due to
very slow infiltration rates. These soils consist primarily of soils with high
water tables, soils with a claypan or clay layer at or near the surface, and
shallow soils over nearly impervious parent material.
If the watershed is homogeneous (i.e., uniform land use and soils) the CN value
can be determined directly from Table 8.03b. Curve numbers for nonhomogene-
ous watersheds may be determined by dividing the watershed into homogeneous
subareas and computing a weighted average.
Step 3. Select design storm and determine runoff depth and volume for erosion
and sediment control using the 10-yr, 24-hr storm.
a. Determine rainfall amount, in inches, from Figures 8.03h through 8.03m
for the selected design storm. (The design storm is based on an SCS Type
' II, 24-hr rainfall distribution.)
8.03.8

-' Rev. 12193
v
Table 8.03b
Runoff Curve Numbers (CN)

A Hydrologic Soil Group
C D
L
Land Use/Cover °?
Cultivated land
without conservation 72 81 88 91
with conservation 62 71 78 81
Pasture land

oor condition
F
68
79
86
89
air condition 49 69 79 84
good condition 39 61? 74 80
Meadow
good condition 30 58 71 78
Wood or forest land
Thin stand - poor cover, no mulch 45 66 77 83
Good stand - good cover 25 X55 70 77
Open spaces, lawns, parks, golf courses, cemeteries, etc.
good condition:
grass cover on 75%
or more of the area 39 61 74 80
fair condition:
grass cover on 50
to 75% of the area 49 69 79 84
Commercial and business
areas (85% impervious) 89 92 94 95
Industrial districts
(72% impervious) 81 88 91 93
Residential:' Development completed and vegetation established
Average lot size Average % Impervious
1 /8 acre or less 65 77 85 90 92
1 /4 acre 38 61 75 83 87
1/3 acre 30 57 72 81 86
1 /2 acre 25 54 70 80 85
1 acre 20 51 68 79 84
2 acre 15 47 66 77 81
Paved parking lots, roofs,
driveways, etc. 98 98 98 98
Streets and roads
paved with curbs and
storm sewers 98 98 98 98
gravel 76 85 89 91
dirt 72 82 87 89
Newly graded area 81 89 93 95
Residential: Development underway and no vegetation
Lot sizes of 1/4 acre 88 93 95 97
Lot sizes of 1/2 acre 85 91 94 96
Lot sizes of 1 acre 82 90 93 95
Lot sizes of 2 acres 81 89 92 94
'Curve numbers are computed assuming the runoff from the house and driveway is directed toward the street.
source: USDA-SCS
8.03.10

Rev. 12/93

Appendices
Ln Ln
Q p '?

t iM .°' ti„ 1 \ \ Ln

.a

J J
CL Ln
0 = +
3

Lr!
1 ao:_ iz;
?'
? ? X17.3
Ln

_ Ln
t

1
l

Figure 8.03h 2-year 1 = i , Ln
day precipitation (inches) \
e
j
Ln Q

8.03.11

i

i

N 8
r a
c Q
E
o ? Q
.a Q

CL
? Q
N
z
cc Q

i

i Figure 8.031 5-year 1 day 1

8
03
12
.
.
u,
10
Li
Ln

Ja' . Ql. ? J ?
L/! a Y; . O
I
l CYO t f
Ir •
;•
u C •?

v
.?
r r
y o

1
h 2
r
ux '?,, 1 j
\

2
1 I• ?"_?=•?,\ i ` J 1
? = oq7 111

3

I J
Li 1 4 •I ? /
W ?-

js V

1
lop

1 s 2,= s 1
-• ?e e?e?•e?,? V1
1 jr r? ?; ? ? 1 ?t
M l• (? '. 2 4
1
1

Ln

?• c .t
-~
,O
.
%

? r

v 1 Y
\? ?•

m (inches) "O
1
1 `LA
fa
d
s
s
S ?
I ?

r7

Appendices
r-
Ln ?'$+
10
o
10
J °
? ly. OL
v p
N g f W :
3J1• ? •\ z i 2 i
.2 00
Ca H N 1. I ??• I ._
CL 9 Q Ln 2 ° 10
Lf;
Lr;
2 ?~
CD
0 r,4
CO ?L %-C-\,- L11
Irv ?? OL °s.Io'? ° , Ln
2 r '
u
10
e
i ? vy / Y
° J Ln
10
l
2 r
? zv%
2
l
s l y CO
Figure 8.03j 10-year 1 day precipitation (inches) 1
V
u _ 1
?` a r
1 `0
8.03.13
i
1 a d
p
Y 4?
IJ Y? ?
1W CO
Ln
ir t I ??
N 8 %0 CO
1 'D I w ??
Ca %0
i ? i. %0
LO w p ?~ 1 t
N Ill : > ?• ? 1
Ln f.
j o Iratw?e?svaCc
to 1 f+! ` ?= J
? ? V V
L_p? o n3^310
1 ; 1 e p 1
Ln
I t: 7 :J. 15 1 r`
CL L
1 a
t
7 Z
%
1
Figure 8.03k 25-year 1 day precipitation (inches)
f •^y CO
0 r`
10
' 8.03.14
4
CO
?Y
Ln II\-?``ye'
-j 7 ? o
r
a
i- 1
G
a V r-- • i
.0 Ln
0
- z z
N g
J
a - a
J ? -
}}}} i o
cc J{
v
r n Z ? C Z= 3 ?,
a `O > 1rl
LO ' `Vitt \ ?[ •'OY.
t
' Figure 8.031 50-year 1 day precipitation (inches)
Appendices
0
1 0.

r
0
>
I
e
S
.CyIE J?4\
N
Li
V

T r`
•
o?
n
d.
8.03.15
c
1 u ?`"??? tr;jam s' •? ; '?
Joe
U Q ( N I• =wen=•III ' T. z` 1???w :
o
I Q
CL _ O o [ 3
I Z
J 1 o I o I MCP' ` \' ..
Q ° r
' 'o 1- -' - t - ?- - ° = I co
s I z 1 ? o
~ Z I I r o /'' z
1
w \ ? I ? M 1
wp %? v 17 Imo. ?
s
z
tf1
1 \ 1 0,
Figure 8.03m 100-year 1 day precipitation (inches) 1 ?l
o,
co
r?V 1
' 8.03.16

u
0
PEAK RATES OF
DISCHARGE FOR
SMALL WATERSHEDS
ON A STEEP SLOPE,
24-HOUR STORM,
TYPE II ,
DISTRIBUTION
i
c
c

V
0
2 5 10 20 50 100 200
DRAINAGE AREA, ACRES
.
Figure 8.03q Discharge vs equivalent drainage area for average watershed slopes 8 - 50%.
F
t
1
I
8.03.20
JVV

2000 l'

Appendices
Table 8.03d
Slope Adjustment Factors
Slope 10• 20 50 100 200
(percent) acres acres acres acres acres
Flat , 0.1 0.49 0.47 0.44 0.43 0.42
0.2 0.61 0.59 0.56 0.55 0.54
0.3 0.69 0.67 0.65 0.64 0.63
0.4 0.76 0.74 0.72 0.71 0.70
0.5 0.82 0.80 0.78 0.77 0.77
0.7 0.90 0.89 0.88 0.87 0.87
1.0 1.00 1.00 1.00 1.00 1.00
1.5 1.13 1.14 1.14 1.15 1.16
Moderate 3 0.93 0.92 0.91 0.90 0.90
4 1.00 1.00' 1.00 1.00 1.00
5 1.04. 1.05 1.07 1.08 1.08
6 1.07 1,10 1.12 1.14 1.15
7 1.09 1.13 1.18 1.21 1.22
Steep 8 0.92 0.88 0.84 0.81 0.80
9 0.94 0.90 0.86 0.84 0.83
10 0.96 0.92 0.88 0.87 0.86
11 '0.96 0.94 0.91 0.90 0.89
12
X13 0.97
0.97 0.95
0.97 0.93
0.95 0.92
0.94
0.94
14 0.98 0.98 0.97 0.96- 0.96
15 0.99 0.99 0.99 0.98 0.98
16 1.00 1.00 1.00 '1.00 1.00
20 1 03 1.04 1.05 1.06 1.07
25 1.06 1.08 1.12 1.14 1.15
30 1.09 1.11 1.14 1.17 1.20
40 1.12 1.16 1.20 1.24 1.29
50. 1.17 1.21 1.25 1.29 1.34
source: USDA-SCS

8.03.23
1

Table 8.03e
Adjustment Factors for Ponding and Swampy Areas
Adjustment factors where ponding and swampy areas occur at the design point.
Ratio of drainage Percentage of
area to ponding
and s ponding and Storm fre uenc ears
wampy area swampy area 2 5 50 - ---1-0-0
7/ 500

200 0.2 0.92 0.94 0.95 0.96 0.97 0.98
t
100 .5 .86 .87 .88 .90 .92 .93

50 1.0
2.0 .80
.74 .81
.75 .83
.76 .85
.79 .87
82 .89
86
w
40
'(? 2.5
3
3 .69 .70 .72 .75 .
.78 .
.82
?
Lp . .64 .65 .67 .71 .75 .78

15 5.0
6
7 .59 .61 .63 .67 .71 .75

J 1 .
10.0 .57
.53 .58
.54 .60
.56 .64
.60 .67
63 .71
68
5 20.0 .48 .49 .51 .55 .
.59 .
.64
C.-
J

I

0

0

u
Adjustment factors where ponding and swampy areas are spread throughout the
watershed or occur in central parts of the watershed
Ratio of drainage Percentage of
area to ponding
and ponding and Storm freq uency ears
_
swampy area swampy area 2 5 1 5
_ 50 100
500
200 0.2 0.94 0.95 0.96 0.97 0.98 0.99

100 .5 .88 .89 .90 .91 .92 .94

50 1.0 .83 .84 .86 .87 .88 .90

40 2.0 .78 .79 .81 .83 .85 .87

30 2.5 .73 .74 .76 .78 .81 .84

20 3.3 .69 .70 .71 .74 .77 .81

15 5.0 .65 .66 .68 .72 .75 .78

10 6.7 .62 .63 .65 .69 .72 .75

5 10.0 .58 .59 .61 .65 .68 .71

4 20.0 .53 .54 .56 .60 .63 .68
25.0 .50 .51 .53 .57 .61 . .66
Adjustment factors where ponding and swampy areas are located only in upper
reaches of the watershed.
Ratio of drainage Percentage of
area to ponding ponding and Storm fre quency (years)
and swampy area swampy area _
2 5 10 25
50 100
500
200 0.2 0.96 0.97 0.98 0.98 0.99. 0.99

100 .5 .93 .94 .94 .95 .96 .97

50 1.0 .90 .91 .92 .93 .94 .95

40 2.0 .87 .88 .88 .90 .91 .93

30 2.5 .85 .85 .86 .88 .89 .91

20 3.3 .82 .83 .84 .86 .88 .89

15 5.0 .80 .81 .82 .84 .86 .88

10 6.7 .78 .79 .80 .82 .84 .86

5 10.0 .77 .77 .78 .80 .82 .84
20.0 .74 .75 .76 .78 .80 .82
8.03.24
Project: Wildcat Lake Dam
Project Number: 06129
Description: Spillway Calculations
Calculated B : JJB Checked B DP
Date: 10/9/2006
Storage Available in Pond Riser + 1 Foot :
Pond surface area @ 3751 = 509,652 SF = 11.70 acres
Crest of dam @ Elev 3754.5; Maximum High water level @ 0100 = 3753.0
Pool at to riser @ 3751 + 1 foot at elevation 3752 = 530,561 SF = 12.18 acres
ume of storage =
` (pool elev. - pond surface elev.
=1 520,1061CF
Determine effect of available storage on QM„ vs Q.
Q;, = Q100 + Base Flow= 425.61+ 2.9 = 428.5 CFS
Tp = to = 18 minutes (see runoff calcs) ' 60 sec/min = 1080 sec
Storage = (Qi, - Qw) ' Tp " 2 (safety factor)
520,106 = ( 428.51- O.J ' 1080 sec 1-2
low = 187.7 CFS
Combined capacity of riser/barrel (principal spillway) and emergency spillway = 187.7 CFS
(Note: Storage is calculated to 1 foot over riser; max pond elevation is 2.0 feet over top riser. This
adds additional storage as safety factor, not including 1.5 foot of freeboard above maximum pond elevation.)
Design principal spillway (ps) and emergency spillway (es) to handle 187.7 CFS
at 2 feet over top riser (leaving 1.5 foot freeboard above maximum pond elevation.)
Max Pond Elev = 3753.0
Determine Flow In Riser/Barrel:
Determine flow through barrel at orifice flow (Q=cdAq(2gh))
Determine flow through riser at orifice flow (Q=cdAq(2gh))
Determine flow into riser at weir flow (Q=c„,LH32)
The least of the three is the allowable flow in the riser/barrel.
To elev. of riser 3751 k7_32.2
Elev. at freeboard 3753 cd= 0.6 (coeff. of discharge)
bottom of riser 3720 c,,,,= 3.0
end of barrel 3716
Dia of riser 72 inches L = 18.8 feet
riser pipe area 28.27 SF H = 2 feet
Dia of barrel 36 inches hbwrel = 31.50 feet
Barrel pipe area 7.07 SF
Height of riser 31 feet
Centerline of barrel 3721.5
1 of 2
t
Barrel orifice
Q = 191.0 CFS
Riser orifice
IQ= 192.5 CFS
Riser (weir)
IQ= 160.0 CFS
The riser calculations are the limiting factor.
QPS = 160.0 CFS
Qart = 187.7 CFS
Clout " Qps = Qes
Qes = 27.6 CFS
Emergency Spillway (Concrete Channel)
D
W I
use: Q = 27.6 CFS
N = 0.015
S = 0.392
Z = 2 :1
W= 2
, D= 0.35
Thus, the combined Clout = 187.7 CFS
Concrete (Table 8.05b)
2of2

Project: Wildcat Lake Dam
Project Number: 06129
Description: Concrete Flotation Block
Calculated By: JJB Checked By: DP
Date: 10/10/2006
' 3751
61
31'
4.51 4
r
' 3720
I
8" Drain = 2.1 SF
36" Barrel = 12.6 SF
72" Riser = 18.9 SF
Water Displaced:

8" Drain = 2.1 *4.5 = 9.41 CF
36" Barrel = 12.6 *6 = 75.42 CF
72" Riser = 18.9 *31 584.35 CF
Total 669.18 CF

Water Displaced =Water Displaced * 7.48 al/CF
Water Displaced = 5005.47 gallons *2.0 Safety Factor
= 10010.94 allons
Weight Displaced = Water displaced ( allons *8.33 lb/gal
Weight Displaced = 83391.13 ounds

Concrete = 150 ound/CF

Volume of Concrete Required = 555.9 CF
t
f
11' 72" Riser

5'6" "

' 36
Barrel
?
I v E:
= J =

lf
i
11' 101

I 5.5'Hi h*1V*11'= 665-.5-CF
Pipe Volumes
Less 8" = 1.57
Less 36"= 9.43
Less 72"= 47.13
58.12

665.5 - 58.121= 607.38 CF Concrete Provided
Vs. 555.90 CF Conc. Required Okay
1 of 1
Project: Wildcat Lake Dam
Project Number: 06129
Description: Rip Rap Outlet Protection Calculations
Calculated B : JJB Checked B : DEP
Date: . 10/11/2006
Pipe diameter = Winches
Pipe Maximum Flow= 160 cfs
d50 Ri rap Size = 1.7 ft = 20.4 inches from Figure 8.06b
d50 Ri ra Size = 24 inches (sizes of rip rap available
Max stone dia dmax = 1.5 X d50 = 3 ft
Outlet stone thickness = 1.5 X dmax 4.5 ft = 54 inches
Appendices
3Qo ??
CI)
_N
a
0
LO
Za?
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (T. < 0.5 diameter).
u
Rev. 12/93
3.06.3
--- """ J
w LUUU
Discharge (ft3/sec)

' Project Description
Project File p:\2006\06129\misc\spillway.fm2
Worksheet Emergency Spillway
' Flow Element Trapezoidal Channel
Method Manning's Formula
Solve For Channel Depth

Input Data
Mannings Coefficient 0.013
' Channel Slope 0.392000 ft/ft
Left Side Slope 2.000000 H : V
Right Side Slope 2.000000 H : V
' Bottom Width 2.00 ft
Discharge 27.60 cfs

Results
Depth 0.35 ft
Flow Area 0.94 ft2
Wetted Perimeter 3.56 ft
Top Width 3.39 ft
' Critical Depth 1.23 ft
Critical Slope 0.002964 ft/ft
Velocity 29.43 ft/s
Velocity Head 13.46 ft
Specific Energy 13.81 ft
Froude Number 9.87
' Flow is supercritical.

Emergency Spillway
Worksheet for Trapezoidal Channel
FlowMaster v5.13
Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 [phone] Page 1 of 1
i
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
APPENDIX B
McGiH
A S S O C I A T E S
'Engineering o Planning • Finance
Post Office Box 2259
Asheville, North Carolina 28802
06129
J / r- P> r
?/ % I mot: - ?v " frtAll-
ATIC
r_
,
J
1.
\J t -4
0 1
or
&e n
r
-D e r
--
??;
'
.1 i
• 0 J I }
_ Ch
I l

f • /
t

It
Iy

rj
1 1 ! ! r"
WV, •
r,
V

Dlo-~~52
YY
lORTH CAROLINA
G
V
~G ~
~ '9 ~ e ~O
"J ~ 4"MALEY ~ N `V 2 7G Zf

C~ 184
~aF ~ ~ PROJECT
Thr C,P Oti ~
194 19E HEAroN rowN of ,94 LOCATION
ANNER ELK
ELK PAR ~ wi~~ cAT ~o O ~C~ gOO~ C~!-
105 ~ LAKE 105 ~2~' ~O
SUGAR MOUNTAINe .~O
221
MINNEAPOLISe 0 ~LLAGE ER nr~ornrnea ~uncE
NEwtANO
~ ~ ° ' ~ ~~P
= QP~
m
~ ~
n 0
~ OANIEL BOONE ~ LINVILLf. e G~ w1LDLIFE MANAGEMENT DnrviEl BOONE IDLiGE ~M~A~AGEMENI O~\~
, ~ AREA V
Vu
~ ~ ~O
~~o ~ GP
BURKE COUNTY lIY
AVERY CO. e AIRPORT W
T ~
o p~NE a R~~~ o
~0 SP 19E ~ 'o McDOWELL COUNTY SCHEDULE OF DRAWINGS
J
a
N O NOT TO SCALE G1 . COVER SHEET -VICINITY MAP
M
O O E1 ...EXISTING CONDITIONS AND DEMOLITION PLAN
N
C1 DAM REPAIR PLAN
3 ~~~11 ~llf~~~ D ,,,NcRo,
~ ~ °°O ~ °eo C2 SITE ACCESS PLAN
e
N , ~ e ~ - SEA °
o a- z55a~ ° a ~ D1 DAM PROFILE AND MISCELLANEOUS DETAILS
~ °°°o ~p °o°°°~/
UL . MIJI:tLLHNtVUS Ut IAILS
o A S S 0 C A T E S ENGINEERING OCTOB Roos
D3 MISCELLANEOUS DETAILS
0 55 BROAD STREET ASHEVILLE> NC 28801 PH. [phone]

1 PROPOSED N0. DATE BY REVISION DESCRIPTION ~ W
LEGEND-EXISTING CONDITIONS ~ ~o \ ~ \ Opp UTILITY POLE \ \ \ I \ \ RIPRAP OUTLET y
\ ~ ~ PROTEC110N (SEE DETAIL Z N
SHEE~D~-} _ I
~ GUY WIRE ANCHOR FO 1 m W¢~
OMH MANHOLE \ ~ \ \ l I (PROP GwM WATER METER ~ \ ~ ~ ~ \ \ \ \ ~I I I ~ (~ILL WATER VALVE EE f~ROPOSED ~ z ~ [-i ~
S~ILLWAY TURNDOWN
\ (EE DETAIL SHEET D3) ~ ' exis~NC ~ w a
1 BEDR CK CHANNEL FOR NALOCAT CREEK
A,„ Fine nroRnNr PROPOSED ~ \ ~ ~ \ ~ \ \ ~ I ~ROP0~SED \ 1
~ cnrcn ensiN/oROa w~Er CONCRETE CONSTRUCTION JOINTS ~ ~ ~ ~ \ ~ ~ ~ ~ 1 I I ~ I Ei 1ERGENCY PILLV~(AY L `°~o' 20'-O" ON CENTER AT CENTERLINE OF SPl4LWAY ~ ~ ~ X I I I 9LLV~(AY LNDS f ~ ~ ~
_ _ _ _ = cuwERr (RADIAL TO CENTERLINE) ~ \ ~ X X X~ S~~N \ \ 1 ~ ~ ~ i i I I I 1X
- X~~ \ ~ ~ PROPOSED ~ g U z z
X f CHECK DAM ~ ~
FMB MAILBOX OR PAPER BOX ~ - oPe POSTAL DROP BOx (TO BE REUSED IN RIPRAP ~F ~ a
orE~. TELEPHONE PEDESTAL 1 I I I IAA ~ I OUTLET PROTECTION) ; o Q ~ p, ~a
PEA. I I O a
FtNCE PROPOSED \ ~ ~ ~ I I d"
TREES/SHRUBS EMERGENCY SPILLWAY ' ~ I ~ ~z
rRee~wE (39.2% SLOPE) ~ ~ f ~ ~ ~`~w
~ ` zQ
~ ~ I ~a
/ ,o e p ,0 20 ao C7 a
ERE30 2F~ EMERGENCY SPILLWAY \ l (I l \ INV. 3716.0 / ~ GRAPHIC SCALE ~ ~ ~
x ~ '
PROPOSED I \ ° 3) ~ ~ PROPOSED / ~ ~ W N
EMERGENCY SPILLWAY ° ~ • ~ r y O
(2~ WIDE CONCRETE CHANNEL) ?0 ~ ' 2:1 SLOPE / / ~P,~ >j~,,
~~s m
BEFORE YOU DIG! /
CALL 1-800-632-4949 PROPOSED ~ '
N.C. ONE-CALL CENTER EMERGENCY SPILLWAY } IT'S THE LAWI
(3.299' SLOPE) 'A / ~ 1 l / ~ \ ~
~p
PROPOSED . ° / I ~ ~
~ ~ ix/ ~ ~ ~
EMERGENCY SPILLWAY BEGINS
EL. 3751.0 X a ' ° ~ / 1 1 ~ I ~ - - \ I \ 330 i ~
. /a / 1
/ ~ Q Q ' / / Z
PROPOSED ~ 1 ~ / PROPOSED ~ J
SPILLWAY TURNDOWN / ~ ~ ~ 1 ` / ~ TEMPORARY SILT FENCE (TYP.) AND D Q
~ X LIMITS OF DISTURBED AREA = 0.6 ACRES Q ~ ~
(SEE DETAIL SHEET D) ~ ' \ 1 ' ~ / /
~ I ~ / / ~ - N 3,¢0 j,~ _ _ _ W W o ~
x ~ /
r ' ~ j ~ ~
~ ~ _
~ / ~
l -
~ ` ~ ~ oJQ Z
l ~l lL ` ~ / \ ~ , / / / / / / ~ / \ 3~zo o
x
I ~ y \ PROPOSED
NOTES: ~ ~ ~ ~ ~ ~ DAM CREST
1.) ALL GRASSED AREAS ON DAM FACES ~ I ~ / ~ EL. 3754.5
SHALL BE MATTED WITH NAG S75 AFTER / ~ ~ / \ eoTron+
SEEDING. ~ / / ' / ~ \ ~ EL. 3718.52
/ ~ , ~
2.) POND SHALL BE COMPLETELY / / ~ ~ ~ ~ PR DRAINED BEFORE AND DURING ~ yo ~ ~ ~ ~ / \ ~ PRI CONSTRUCTION BY SIPHONS, PUMPS, OR ~ / ~ ~ / ~ ~ wnreR 170
\ PROPOSED '/j / ~ ~ ~ ~ ~ N p}[
`PRIMARY SPIIIWAY' / ~ ~ _ / ~ ~ ; rER 1J0 LF 36" DIP / _ a
OTHER MEANS, AND DISCHARGED INTO ~ ~ / ~ / ~ ~ ~ ~ ~ ~ / I i + /
STREAM UPSTREM OF CHECK DAM. NO / -~{ii I
SILTATION OF DOWNSTREAM WILL BE / ~ ~ ~ ~ ~ / ~ ~
ALLOWE0. / / ~ ~ ~ / % , ~a° J _ - ~ ~F;
~ ~ i ~ J ~
~ I i ` ` ~ Nam I I
I ~ ~ ~ ~ ~ ~ ~ /
/ ~ j PR~OP~SE~= ~mv~,}~ww
~ O m J W W ~ ~ AM C EST , o°aZmz~
I I f / N~TALC~BAiR/RH~CSNARET~H AM T9 / ~ i
V` D ~ N / J ~ ~ m~ Q VI O N Z
N{ATE~RIIGF~T ~AST~/ ~ ~ ~ ~ O 4 U w¢ W O \ ~ I / ~ / D l~ O U D U
PROPOSED ~ / ~ ~ ~ ~
NORMAL POOL AFTER ~ ~ ~ ~ ~ / ~ ~ / ~ , 340
/ ~ I ~~;~ZIn. W.CH LR~~ /
EL~.N3751.O110N / ~ / ~ / ~ ~ ~ ~ ~ ~ / ~ ~ ~
o ~ ~ / 2~~ E 3'30
1 / / / \ \ PROPf~S D ~ ~~b~ n'
a j ~ / UM~S OF DISTUR~D AREA = 0.6 ACRES
,w~ / ~ P jO~OSED ~ W
~ ~ j ~ h1AUL RQAAD WITH 6" RAILROAD BALLAST
~ / / / / ~ / / / RISER INV. EL. 3720A
f / / / / 3>20 J,,~' / / / r ~ ~ ~ / ~ SEE EET C2
~ / ~ ~ ~ / / ~ / / / /PROPOSED \ /
U / / ~ / / / / ~ / / / ~ / ~ / ~ / / / / WITH' COLD WATER RETURN RISER ~ / ~ ~ / PROPOSED ~ SHELTER
~ / / / / ~ / ~ ~ / TOP EL. 3751 A ~ / / ~ / N / / J ~ G~ENCfi FOR INURE / J ~ f ~ / ~ / /
/ , ~ , ~ ~ ~ / ~ / / ~ / / ~ BOTTOM EL. 3720.0 A ~ , / ~
o ~
/ WILDCAT LAKE ~ /PROXIM#E o~, HEMLocK SHEET
° JIM H U E &C Assq(IATPS, P LAKE BOTTOM o / EL. 3720,89
PROF SStONAL LAND S'URVEYJR PROPOSED / 11 1~~ .MAPLE j(DO( NOT DISTURB)
a Y10, BO 1452 BURN LLE NORTH C OUNA 8714 / SALE; 17,-- 10 / $ FLANGED RESILIENT 10
SEAT GATE VALVE NOTE: LOCATIONS OF EXI TING TILITIE AS SHO ARE HONM ARE ONLY.,' r\ , 1
EXACT LOCATION ARE 0 BE RIFIED IN THE IELD BY -/FIELD BY HE CON ACTOR.