20240486 Ver 1_WRC Comments_20240429

® North Carolina Wildlife Resources Commission 9
Cameron Ingram, Executive Director
April 29, 2024
Ms. Amanda Fuemmeler
U.S. Army Corps of Engineers, Regulatory Branch
151 Patton Avenue, Room 208
Asheville, North Carolina 28801-5006
SUBJECT: Pigeonroost Pond Modification
Pigeonroost Creek, Watauga County
Dear Ms. Fuemmeler:
Biologists with the North Carolina Wildlife Resources Commission (NCWRC) reviewed an
application to dredge a pond, install a new outflow device, restore a reach of stream, and expand
a driveway, impacting at least 157 ft of Pigeonroost Creek and 0.087 acre of wetland in Watauga
County. Our comments on this application are offered for your consideration under provisions of
the Clean Water Act of 1977 (33 U.S.C. 466 et. seq.) and Fish and Wildlife Coordination Act (48
Stat. 401, as amended; 16 U.S.C. 661-667d).
There are Rainbow Trout in Pigeonroost Creek, and project activities should be avoided from
January 1 to April 15 to minimize impacts to trout reproduction. Rainbow Trout are sensitive to
excess sediment, so excellent erosion and sediment control is needed for this project.
The application proposes to dredge an existing pond, retrofit the spillway system, and install a
new riser. The riser will incorporate an adjustable coldwater release device. A reach of stream
that is braided downstream of the pond will be restored to a single channel. Flows will be
pumped around the pond during all in -pond work.
We offer the following recommendations to minimize impacts to the aquatic community:
1. Project activities should be avoided between January 1 and April 15 to minimize impacts to
trout reproduction.
2. Vigilance should be used in sediment and erosion control during site preparation,
construction, and clean up. Disturbed areas should be seeded, mulched and/or matted as
soon as possible.
3. Flows must be maintained downstream at all times, including during pond refill. We
recommend maintaining at least 50% of incoming flows in the downstream channel.
Mailing Address: Habitat Conservation • 1721 Mail Service Center • Raleigh, NC 27699-1721
Telephone: [phone] • Fax: [phone]

Pigeonroost Pond Modification Page 2 April 29, 2024
Pigeonroost Creek, Watauga Co
4. The coldwater release structure is adjustable. It should always be in use.
Thank you for the opportunity to review and comment on this project. Please contact me at
[phone] if you have any questions about these comments.
Sincerely,
Andrea Leslie
Mountain Region Coordinator, Habitat Conservation Program
cc: Adam Williams, Brushy Fork Environmental Consulting
Seren Homer, NC Division of Water Resources

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)
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 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.
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.