20011729 Ver 1_Approval Letter_20051205

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December 5, 2005
Town of Siler City
Attn: Mr. Joel Brower
PO Box 769
Siler City, NC 27344-0769
Alan W. Klimek, P.E. Director
Division of Water Quality

Re: Construction/Expansion of the Existing Rocky River Lower Reservoir, Chatham County
DWQ Individual Water Quality Certification No. 3482
DWQ Individual Isolated Wetland Permit No. 14
DWQ Project No. 01-1729
USACE Action ID. No. 200220234
APPROVAL of 401 Water Quality Certification & Isolated Wetland Permit
Dear Mr. Brower:
Attached hereto is a copy of revised Certification No. 3482 issued to the Town of Siler City, NC, dated
June 28, 2005. This Certification approval shall also act as your approved Isolated Wetland Permit. In
addition, you should get any other federal, state or local permits before you go ahead with your project
including (but not limited to) 404 Permit, Erosion and Sediment Control, Stormwater, Dam Safety, Non-
discharge and Water Supply Watershed regulations. This Certification replaces the one issued to you on
June 28, 2005.
If we can be of further assistance, do not hesitate to contact us.
AWK/BDIcbk
Attachments: Certificate of Completion
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Sincerely,
Alan W. Klimek, P.E.
cc: U.S. Army Corps of Engineers, Raleigh Regulatory Field Office
Wilmington District, USACOE
DWQ Raleigh Regional Office
DLR Raleigh Regional Office
Jim Mead, DWR
US Fish & Wildlife. Service, Raleigh Field Office, PO Box 33726, Raleigh, NC 27636-3726
N.C. Division of Wildlife Resources
DWQ 401 Oversight / Express Permitting Unit
Boyd DeVane, DWQ Planning Branch
File Copy
Central Files
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:/lh2o.enr.state.nc.us/ncwetiands
No°e Carolina
W,W11rY
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Town of Siler City /DWQ Project No. 01-1729
Page 2 of 7
December 5, 2005
NORTH CAROLINA 401 WATER QUALITY CERTIFICATION
& ISOLATED WETLAND PERMIT
THIS CERTIFICATION (Individual Water. Quality Certification No. 3482) is issued in
conformity with the requirements of Section 401 Public Laws 92-500 and 95-217 of the United
States and subject to the North Carolina Division of Water Quality (DWQ) Regulations in 15
NCAC 2H, Section.0500 to the Town of Siler City for impacts to 9,027 feet of perennial stream
channel, 1,588 feet of intermittent stream channel, and 7.67 acres of jurisdictional wetlands in the
Cape Fear River Basin, associated with the construction/expansion of the existing Rocky River
Lower Reservoir in Chatham County, North Carolina, pursuant to an application filed on the 27th
day of November of 2001, and including modifications and additions as described within the
Public Notice issued by the U.S. Army Corps of Engineers dated July 15, 2004.
This letter shall also act as your approved Isolated Wetland Permit. This Permit (Individual
Isolated Wetland Permit No. 14) is issued in conformity with the requirements of the North
Carolina Division of Water Quality (DWQ) Regulations in 15 NCAC 2H, Section 0.1300 to the
Town of Siler City for impacts to 1.52 acres of isolated wetlands in the Cape Fear River Basin,
associated with the construction/expansion of the existing Rocky River Lower Reservoir in
Chatham County, North Carolina, pursuant to an application filled on May 19, 2003 and
including modifications and additions as described within the Public Notice issued by the U.S.
Army Corps of Engineers dated July 15, 2004.
The application and supporting documentation provides adequate assurance that the proposed
work will not result in a violation of applicable Water Quality Standards and discharge
guidelines. Therefore, the State of North Carolina certifies that this activity will not violate the
applicable portions of Sections 301, 302, 303, 306, 307 of PL 92-500 and PL 95-217 if
conducted in accordance with the application, the supporting documentation, and conditions
hereinafter set forth.
This approval is only valid for the purpose and design submitted in the application materials and
as described in the Public Notice. If the project is changed, prior to notification a new
application for a new Certification is required. If the property is sold, the new owner must be
given a copy of the Certification and approval letter and is thereby responsible for complying
with all conditions of this Certification. Any new owner must notify the Division and request the
Certification be issued in their name. Should wetland or stream fill be requested in the future,
additional compensatory mitigation may be required as described in 15A NCAC 2H .0506 (h) (6)
and (7). If any plan revisions from the approved site plan result in a change in stream or wetland
impact or an increase in impervious surfaces, the DWQ shall be notified in writing and anew
application for 401 Certification may be required. For this approval to be valid, compliance with
the conditions listed below is required.
Conditions of Certification & Isolated Wetland Permit:
1. Impacts Approved - The following impacts are hereby approved as long as all of the
conditions of this Certification and Isolated Wetland Permit are met. No other impacts are
approved including incidental impacts.
Town of Siler City / DWQ Project No. 01-1729
Page 3 of 7
December 5, 2005
Amount Approved
(Units)
Perennial Stream 9,027 feet)
Intermittent Stream 1,588 (feet)
404 Wetlands 7.67 (acres)
Isolated Wetlands 1.52 (acres)
2. Compensatory Mitigation (Final Plan Needed) - Mitigation must be provided for the
proposed impacts as specified by the USACE and must include a minimum of 7.67 acres of
wetland restoration and/or creation. A final compensatory mitigation plan (based on the Draft
Wetland & Stream Mitigation Plan dated May 24, 2004) must be approved in writing by the
DWQ Office before any of the impacts approved herein are conducted. Additionally, the
compensatory mitigation plan must be completely constructed and implemented according to
the plans approved by DWQ. The mitigation must be maintained according to the approved
plan and permanently protected by the use of conservation easements or similar protections.
Any repairs or adjustments to the mitigation site must be made according to the approved
plan or must receive written approval from DWQ to make the repairs or adjustments.
3. The terms of condition set forth in this document shall become a management strategy that
will be implemented by the Town under the oversight of the Director of the Division of
Water Quality. There will also be developed a Reservoir Management Team which will
guide the Division of Water Quality in its efforts to ensure the optimum operation of the
reservoir for the protection and improvement of the quality of the Rocky River. A major part
of the reservoir strategy will be to simulate storm events by releasing pulses of water from
the new control structure with the intent to mimic natural flow and dislodge filamentous algal
mats that occur along the river. The volume, velocity and duration needed to improve the
quality of the river will be evaluated by the Reservoir Management Team based on studies
undertaken while Siler City is drawing 4 mgd from the new control structure. When Siler
City begins to pull more than 4 mgd, the management strategy, as outlined in this document,
will be reviewed to determine if adjustments are needed under the new flow regime. The
amount of water required to provide the pulses will be such that at least a 20 cfs pulse for a
12-hour period can be released from the dam and the number of required pulses will be
limited to one pulse every thirty (30) days. The River Management Team shall consist of
representatives from at least the Division of Water Quality, Division of Water Resources,
N.C. Wildlife Resources Commission and US Fish and Wildlife Service, the Town of Siler
City and the Friends of the Rocky River organization (unless the agencies decline to be
represented on the Team).
4. The Town will ensure there is a "pulse" release of 20 cfs for a 12-hour period every 30 days
whenever the aggregate storage remaining in the two reservoirs is greater than 40 percent
(Tiers 1 and 2.) Pulses are only required when no natural events of similar magnitudes are
observed.
5. Division of Water Resource Conditions incorporated as conditions of this Certification shall
include:
Town of Siler City / DWQ Project No. 01-1729.
Page 4 of 7
December 5, 2005
1. Minimum Flow Regime - During development of the environmental assessment for this
project, the Town agreed to a minimum release regime to maintain aquatic habitat
downstream of the expanded reservoir. There are three tiers of minimum flows -
depending on the combined volume of usable storage available in both the upper and
lower reservoirs on the Rocky River. The triggers for each tier as follows:
• Tier 1 - releases to be made when the combined usable storage of both the upper and
lower reservoirs is greater than or equal to 70 percent of the combined total usable
storage.
• Tier 2 - releases to be made when the combined usable storage is less than 70 percent,
but greater than or equal to 40 percent of the total usable volume.
• Tier 3 - releases to be made when the combined usable storage is less than 40 percent
of the total usable volume.
5.2. The quantity of the release varies by month and tier, and is shown in the table below.
During initial filling of the new reservoir the minimum release should be made at tier 1
levels, rather than following the tiers in reverse order.
Minimum Release in
CFS
Month Tier 1 Tier 2 Tier 3
JAN 6.0 3.5 0.5
FEB 6.0 3.5 0.3
MAR 6.0 3.5 0.3
APR 9.0 4.5 0.3
MAY 8.0 4.0 0.3
JUN 5.0 2.0 0.3
JUL 2.5 1.0 0.3
AUG 2.0 1.0 0.3
SEP 2.0 1.0 0.3
OCT 3.5 2.0 0.3
NOV 5.0 2.5 0.5
DEC 7.0 3.5 0.5
5.3. Reductions in Withdrawals in Conjunction with Tier 2 or Tier 3 Minimum Releases -
Water supply withdrawals from the Rocky River will be reduced by ten percent when
the release is reduced from tier 1 to tier 2, and by another ten percent (20 percent total)
when minimum releases are reduced from tier 2 to tier 3 levels. The amount of
reduction in withdrawal will be based on the average daily withdrawal for the 60-day
period immediately prior to the first reduction in minimum release. The water supply
operator shall achieve each reduction in withdrawal within two weeks of each reduction
in minimum release. The water system operator shall document reduction in water
withdrawals by submitting reports of daily water withdrawals to the Department. The
reports should also include daily readings from the minimum release metering system at
the dam. These reports shall be submitted every two weeks for as long as the minimum
release is reduced below tier 1 levels.
Town of Siler City / DWQ Project No. 01-1729
Page 5 of 7
December 5, 2005
5.4. Water Quality and Minimum Release Design - The plans for the minimum release
structure submitted by the Town indicate that water would be drawn from a depth of 5
feet off the bottom of the impoundment. The Division of Water Quality was consulted
to see if there would be the potential for reservoir stratification and release of water with
low levels of dissolved oxygen using the proposed design. After reviewing data for the
upstream reservoir on Rocky River, DWQ concluded that there is a definite potential for
stratification and low dissolved oxygen levels from the proposed depth of the release for
minimum flows. The upstream reservoir has shown strong stratification and dissolved
oxygen levels as low as 1 milligram per liter (mg/1) at depths of about 6 feet from the
surface (the proposed design would be about 15 feet below the normal pool level). State
water quality standards set the minimum level for dissolved oxygen at 4 mg/1
instantaneous and 5 mg/l daily average.
To avoid potential downstream water quality problems, the outlet structure shall be
designed so that the minimum release can be drawn from at least three levels in the
impoundment. These levels should be: two feet below normal pool; seven to eight feet
below normal pool; and from the currently planned level of five feet off the bottom. It is
anticipated that under most circumstances the release would come from the uppermost
level, with the others being used if impoundment levels are temporarily reduced. The
consultant should work with the Dam Safety program of the Division of Land Resources on
options to accomplish the goal of being able to withdraw water from at least three levels
(top, middle, and bottom) of the reservoir.
5.5. Downstream Gaging - The Town submitted plans for metering the minimum release at the
outlet from the dam. These plans are acceptable as long as the metering system is
calibrated with field measurements after the new reservoir has filled, and at least every
two years thereafter. Calibration measurements should be provided to the Department
within 30 days of completion.
During review of the environmental assessment for this project, concerns were raised
regarding downstream flows and habitat for aquatic species - including federally listed
endangered species. It will be important to monitor flows in the Rocky River to ascertain if
the minimum release is conveyed downstream without excessive channel loss, and to make
sure that assimilative capacity flows in the vicinity of the confluence with Loves Creek are
maintained.
Because both the quantity and quality of water released downstream to the Rocky. River are
so critical, the Town - in cooperation with the USGS - shall install and maintain a
continuous recording gage in the vicinity of U.S. Highway 64, upstream of Loves Creek.
This gage shall be equipped to monitor both stream discharge and water quality. Water
quality parameters to be monitored shall include dissolved oxygen, temperature, pH, and
conductivity. After reviewing the water quality data collected over a 5-year period
following filling of the new reservoir, the agencies and the River Management Team
developed as provided above will evaluate if it will be necessary to continue monitoring
water quality parameters.
Town of Siler City / DWQ Project No. 01-1729
Page 6 of 7
December 5, 2005
Plans for the gauging described above shall be submitted to the Department for approval
prior to installation.
6. The Town of Siler City's Unified Development Ordinance shall include:
• Minimum buffer requirements along the Rocky River, perennial tributaries and
intermittent tributaries within the Town's ETJ to between 50 and 200 feet. A 200-foot
buffer imposed along the entire reach of the Rocky River within the Town's planning .
area and along all perennial and intermittent streams within 2,500 feet of the Rocky
River. Beyond 2,500 feet, the buffer requirement shall be 100 feet for perennial streams
and 50 feet for intermittent streams within the Town's jurisdiction. Areas within the
Town's jurisdiction but outside of the Rocky River subbasin are required to have 100-
foot buffers on perennial streams and 50-foot buffers on intermittent streams. The
definition of intermittent and perennial streams shall be similar to definitions used by the
DWQ within the Neuse Buffer Rule, 15A NCAC 02B .0233;
• All new developments shall limit impervious surfaces by limiting/discouraging the use of
curb and gutter and requiring grassed swales where the slope is less than 5%;
• Stormwater controls shall be required for any new development exceeding 7 percent
impervious surface area;
The direct discharge of stormwater via ditches or pipes in or through buffer areas shall be
prohibited unless otherwise treated through best management practices. Alternate
stormwater discharge methods, such as infiltration practices, shall be encouraged over the
use of detention ponds.
7. A fenced 100-foot vegetative buffer shall be maintained at a minimum around the expanded
reservoir, except for encroachments described in pages 34-39 of the Final Mitigation Plan,
including a paved state road, an electric transmission line, a cabin and a dam of a pond. All
wetlands and stream channels within this buffer shall be preserved, enhanced or restored, as
appropriate.
8. 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:
8.1.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.
8.2.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.
9. 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 404/401Permit Application. All
construction activities, including the design, installation, operation, and maintenance of
Town of Siler City / DWQ Project No. 01-1729
Page 7 of 7
December 5, 2005
sediment and erosion control Best Management Practices, shall be performed so that no
violations of state water quality standards, statutes, or rules occur;
10. 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;
11. The Town of Siler City and its contractors shall conduct construction activities in a manner
consistent with State water quality standards and any other appropriate requirements of State
law and federal law. If the Division determines that such standards or laws are not being met
during construction or subsequent operation of the dam, or that State or federal law is being
violated, or that further conditions are necessary to assure compliance, the Division may
reevaluate and modify this Certification to include conditions appropriate to assure water
quality compliance in accordance with 15A NCAC 2H.0507(d). Before modifying the
Certification, the Division shall notify the US Army Corps of Engineers, provide public notice
in accordance with 15A NCAC 2H.0503 and provide opportunity for public hearing in
accordance with 15A NCAC 2H.0504. Any new or revised conditions shall be provided to the
Director in writing, shall be provided to the United States Army Corps of Engineers for
reference in any Permit issued pursuant to Section 404 of the Clean Water Act, and shall also
become conditions of the 404 Permit for the project;
12. Certificate of Completion - Upon completion of all construction and mitigation work approved
within the 401 Water Quality 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;
Other condition:
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 Permit.
If this Certification and Isolated Wetland Permit is unacceptable to you, you have the right to an
adjudicatory hearing upon written request within sixty (60) days following receipt of this
Certification. This request must be in the form of a written petition conforming to Chapter 150B
of the North Carolina General Statutes and filed with the Office of Administrative Hearings,
6714 Mail Service Center, Raleigh, N.C. 27699-6714. If modifications are made to an original
Certification, you have the right to an adjudicatory hearing on the modifications upon written
request within sixty (60) days following receipt of the Certification. Unless such demands are
made, this Certification shall be final and binding.
This the 5th day of December, 2005
DIVISION OF WATER QUALITY
41-14 ?- CJ'-
?il Alan W. Klimek, P.E.
AWK/BD/bz/cbk rev ?1