20160321 Ver 1_WRC Comments_20161118

® North Carolina Wildlife Resources Commission
Gordon Myers, Executive Director
November 18, 2016
Mr. David Brown
U.S. Army Corps of Engineers, Regulatory Branch
151 Patton Avenue, Room 208 ;'
Asheville, North Carolina 28801-5006
SUBJECT: Highlands Biological Station
UT to Mill Creek, Macon County
Dear Mr. Brown:
Biologists with the North Carolina Wildlife Resources Commission (NCWRC) reviewed an application to
impact 0.04 acres of wetland and 69 feet of an unnamed tributary (UT) to Mill Creek associated with
Ravenel Lake in Highlands, Macon County. I visited the site with the project designer and Highlands
Biological Station in April of this year. 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).
The project should not impact wild trout, and project activities do not need to be avoided during the trout
moratorium. Ravenel Lake has a wetland fringe of varied width around its perimeter; the wetland has
many characteristics of a Southern Appalachian Bog, including numerous bog plant species resulting from
intentional planting and natural recruitment. The lake impounds several streams that are UTs to Mill
Creek.
The project proposes to build an outdoor classroom, resulting in 0.04 acres of wetland fill and 69 feet of
impact to a UT to Mill Creek. The lower end of the stream channel will be filled and the stream
redirected to the open water of the lake in another location. The classroom will be built on pilings placed
in the open water portion of the lake. The dam will be reinforced and a coldwater siphon installed in
order to transform the lake release from a topwater spillway to a siphon that will pull water from the
lower 1/3 of the lake.
It is unclear if there will be temporary impacts to wetlands during construction associated with equipment
mobilization; these impacts should be minimized by keeping the footprint small and using mats to
minimize soil disturbance. Details are not provided for the methods that will be used to control sediment
loss from the construction site; it is important to retain sediment on site.
In order to construct the outdoor classroom in the dry, lake levels will be lowered with pumps until the
coldwater siphon is in place, after which lake levels will be adjusted with the siphon. Downstream flows
Mailing Address: Habitat Conservation • 1721 Mail Service Center • Raleigh, NC 27699-1721
Telephone: [phone] • Fag: [phone]

Highlands Biological Station Page 2 November 18, 2016
UT Mill Creek, Macon County
.will be maintained, and during lake refill, a proposed flow of greater than 40 gal/min (or 0.09 cfs) will be
maintained. We recommend that minimum flows during refill be either 50% of incoming flows or the
30Q2 value. Using the flow statistics for the Mill Creek site in Giese and Mason (1993) as a reference,
we estimated flow statistics for Lake Ravenel by applying a ratio of the Ravenel Lake drainage area (0.3
mit) to that of the Mill Creek gauged site (1.15 miz). This results in an estimated 7Q10 of 0.08 cfs, a
30Q2 of 0.23 cfs, and a mean annual flow of 1.05 cfs.
We appreciate the Highland Biological Station's efforts to improve outflows from Ravenel Lake by
installing a coldwater siphon. We are supportive of the objective to create an outdoor classroom, as well.
We offer the following recommendations to minimize impacts to fish and wildlife resources: _
1. Work should be accomplished as quickly as possible and vigilance used in sediment and erosion
control during site preparation, construction, and clean up. Disturbed areas should be seeded,
mulched and matted as soon as possible. Sediment and erosion controls should be installed to retain
sediment in the work area and out of the lake.
2. Lake drawdown should be accomplished with pumps set at the surface of the lake in order to
minimize sediment release downstream. Once the coldwater siphon is on line, it is important to
monitor the turbidity of the outflows; if outflows are turbid due to sediment loss from construction
activities, then activities should cease. If surface pumps can maintain appropriate lake levels and
reduce turbidity in outflows, then they should be used instead.
3. Any erosion control matting used be free of plastic or nylon mesh, as this type of mesh netting
frequently entangles wildlife and is slow to degrade, resulting in a hazard that may last for years.
4. Downstream flows should be maintained at all times, and during lake refill a minimum of 50% of the
incoming flows or the 30Q2 flow of 0.23 cfs maintained.
5. Temporary impacts to wetlands should be minimized. Any areas impacted should be replanted with
native species.
6. Wetland areas to be permanently and temporarily impacted should be surveyed for rare plants and
these plants transplanted to other areas of the wetland before impacts.
Thank you for the opportunity to review and comment on this project. Please contact me at (828) 558-
6011 if you have any questions about these comments.
Sincerely,
Andrea Leslie
Mountain Region Coordinator, Habitat Conservation Program
ec: Philip Ellis, Robinson Design Engineers
Jim Costa, Highlands Biological Station
Tim Fox, NC Division of Water Resources
Byron Hamstead, US Fish and Wildlife Service