20120658 Ver 1_WRC Comments_20120808

IQ North Carolina Wildlife Resources Commission 9
Gordon Myers, Executive Director
MEMORANDUM
TO: Eric Alsmeyer, Raleigh Regulatory Field Office
U.S. Army Corps of Engineers
FROM: Shari L. Bryant, Piedmont Region Coordinator �� P
Habitat Conservation Program �l
DATE: 8 August 2012
SUBJECT: Public Notice for Duke University for Construction of the Duke University Water
Reclamation Pond, Durham County, North Carolina. Corps Action ID #: SAW -2012-
01043.
Biologists with the North Carolina Wildlife Resources Commission (NCWRC) have reviewed the
subject public notice. Our comments are provided in accordance with provisions of the Clean Water Act
of 1977 (as amended), Fish and Wildlife Coordination Act (48 Stat. 401, as amended; 16 U.S.C. 661 -
667e), and North Carolina General Statutes (G.S. 113 -131 et seq.).
The applicant proposes to permanently impact 1,674 linear feet of perennial stream channel for
construction of a 5.52 acre water reclamation pond on an unnamed tributary to Sandy Creek in the Cape
Fear River basin. The purpose of the project is to provide a consistent non - potable water source for a
centralized chiller plant for Duke University, and to offset demand to the City of Durham's drinking
water supply. The applicant is proposing onsite compensatory mitigation that includes restoration and
enhancement of 3,249 linear feet of a perennial stream that drains to Sandy Creek on the Duke University
Central Campus. Also, to mitigate for impacts, the applicant has proposed to construct a wetland bench
along the edge of the pond, provide a minimum flow release, construct a riprap apron spillway to provide
diffuse flow and oxygenation, and maintain or establish a vegetated riparian buffer around the pond.
Construction of instream dams can modify stream flows, affect water quality, and alter the natural
diurnal, seasonal, and annual patterns of the upstream and downstream movements of instream biota
(Yeager 1993). Also, there is the potential for downstream stream bed erosion and degradation caused by
outfall waters that are relatively free of sediment (Kondolf 1997). Generally, NCWRC recommends that
small impoundments be located off - channel and wetlands be avoided.
The Division of Water Resources (DWR) indicates the proposed dam does not meet the minimum
threshold for establishing a minimum flow release (i.e., 7Q 10 greater than 0.2 cubic feet per second or a
point source discharge in the affected reach). The applicant has used stream gages to measure baseflow
and it was determined to be 0.289 cfs. Although DWR does not mandate a minimum flow release, the
Mailing Address: Division of Inland Fisheries • 1721 Mail Service Center • Raleigh, NC 27699 -1721
Telephone: [phone] • Tax: (919) 707 -0028

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8 August 2012
Duke Water Reclamation Pond
Corps Action ID #: SAW- 2012 -01043
design of the intake riser structure would allow for at least one -half of the baseflow to pass downstream
year- round. We are pleased to see the applicant is proposing to maintain a minimum flow release even
though it is not required. This should help to minimize downstream aquatic impacts. Also, we are
pleased to see the applicant is proposing to construct a wetland bench, maintain a vegetated buffer, and
perform stream restoration within the impacted watershed. These too should help to minimize impacts to
aquatic and terrestrial wildlife resources.
Should the permit be issued, we offer the following recommendations to further minimize
impacts to aquatic and terrestrial wildlife resources.
1. The outflow pipe should be designed to draw water within 1 to 2 feet of the bottom, but not on
the bottom. This design will prevent buildup of poorly oxygenated water and improve water
quality in the pond. The discharge should be aerated to enhance dissolved oxygen levels.
2. Outflow water temperatures and dissolved oxygen should be monitored. Outflow water
temperatures should be compared to inflow water temperatures and should not exceed the
temperature standard for piedmont streams.
3. Concrete is toxic to aquatic life and should not be allowed to come in contact with surface waters
until cured.
4. Residual flow in the stream below the dam must be maintained during filling of the impoundment
to protect aquatic life. However, turbid water should not be discharged. Until water in the
impoundment is clear, flexible pipe should be used to maintain any stream flow around the
impoundment.
5. All mechanized equipment operated near surface waters should be inspected and maintained
regularly to prevent contamination from fuels, lubricants, hydraulic fluids or other toxic
materials.
6. Rock, sand, or other materials should not be excavated from the stream channel except in the
immediate permitted area. Also, sandbags, flexible pipe, or other stable diversion structures
should be used to avoid excavation in flowing water.
7. A plan should be developed to manage sediment behind the dam. Potential examples include
periodic flushes (thorough sediment analysis and prior assessment of the foreseeable effects of
releasing sediment must be included) and sediment removal (passive techniques are preferred
such as sediment trapping devices).
8. Native wetland species should be planted in the wetland bench, and native trees or shrubs should
be planted in the riparian buffer. Using native species instead of ornamentals should provide
benefits by reducing the need for water, fertilizers, and pesticides.
9. If the applicant proposes to stock fish in the impoundment, then only native piedmont species
should be stocked. A stocking permit from the NCWRC is required to stock any species of fish,
mollusks, or crustaceans in the public inland fishing waters of North Carolina. Applications for a
stocking permit are available at http: / /www.newildlife.ar F. There is no fee associated with the
permit application process.
10. If fish are stocked in the impoundment, then the outlet structure should be screened to prevent
migration of fish out of the impoundment. Also, to minimize impingement and entrainment of
fish in the water intake structure, it should be designed with passive screens and openings not to
exceed one centimeter and with a maximum intake velocity of 0.5 fps (feet per second).

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8 August 2012
Duke Water Reclamation Pond
Corps Action ID #: SAW- 2012 -01043
11. Sediment and erosion control measures should be installed prior to any land clearing or
construction. These measures should be routinely inspected and properly maintained. Excessive
silt and sediment loads can have numerous detrimental effects on aquatic resources including
destruction of spawning habitat, suffocation of eggs, and clogging of gills of aquatic species.
Thank you for the opportunity to comment on this project. If we can be of further assistance,
please contact our office at (336) 449 -7625 or shari.bryant(ainewildlife.org.
Literature cited
Kondolf, G.M. 1997. Hungry water: effects of dams and gravel mining on river channels.
Environmental Management 21:533 -551.
Yeager, B. L. 1993. Dams. Pages 57_114. In C. F. Bryan and D. A. Rutherford, editors. Impacts on
warmwater streams: Guidelines for evaluation. Southern Division, American Fisheries Society, Little
Rock, Arkansas.
ec: Ian McMillan, NCDWQ