NC 18 (2)

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NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Colson H. Sullins Dee Freeman
Governor Director Secretary
September 18, 2009
SEP 2.2 2009
DENR - WATER QUALITY
MEMORANDUM - WETLANDS AND STORMWATER BRANCH
To: Melba McGee, Environmental Coordinator, Office of Legislative and Intergovernmental
Affairs
From: Amy Euliss, Division of Water Quality, Winston Salem Regional Office
Subject: Comments on the Finding of No Significant Impact related to proposed NC 18 (Sparta
Road) Improvements from existing SR 1002 (Mountain View Road) to ExistinOR 1717
(Yellow Banks Road), Wilkes County, State Project No. 6.761019, TIP R-340
This office has reviewed the referenced document dated June 2009. The NC Division of Water Quality
(NCDWQ) is responsible for the issuance of the Section 401 Water Quality Certification for activities that
impact Waters of the U.S., including wetlands. It is our understanding that the project as presented will
result in impacts to jurisdictional wetlands, streams, and other surface waters. NCDWQ offers the
following comments based on review of the aforementioned document:
Project Specific Comments:
If Any Class WS CA:
Review of the project reveals the presence of surface waters classified as Water Supply Critical
Area in the project study area. Given the potential for impacts to these resources during the
project implementation, NCDWQ requests that DOT strictly adhere to North Carolina regulations
entitled "Design Standards in Sensitive Watersheds" (15A NCAC 04B .0124) throughout design
and construction of the project. This would apply for any area that drains to streams having WS
CA(Water Supply Critical Area) classifications.
2. If Any Class IIQW:
Review of the project reveals the presence of surface waters classified as WS II; High
Quality Waters of the State in the project study area. This is one of the highest
classifications for water quality. Pursuant to 15A NCAC 2H .1006 and ISA NCAC 2B
.0224, NC DOT will be required to obtain a State Stormwater Permit prior to construction
except in North Carolina's twenty coastal counties.
General Comments:
3. The environmental document shall provide a detailed and itemized presentation of the proposed
impacts to wetlands and streams with corresponding mapping. If mitigation is necessary as
required by 15A NCAC 2H.0506(h), it is preferable to present a conceptual (if not finalized)
mitigation plan with the environmental documentation. Appropriate mitigation plans will be
required prior to issuance of a 401 Water Quality Certification.
Transportation Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internal: http:l/h2o.encstate.nc.uslncwetands/
NorthCarolina
Natimally
An Equal eppommity1 Affirmative Action Employer
4. Environmental assessment alternatives shall consider design criteria that reduce the impacts to
streams and wetlands from storm water runoff. These alternatives shall include road designs that
allow for treatment of the storm water runoff through best management practices as detailed in
the most recent version of Siormwater Best Management Practices, such as grassed swales,
bu£fer'aceas; preformed scour holes, retention basins, etc.
5. Afte the selection of the preferred alternative and prior to an issuance of the 401 Water Quality
Certification, the NCDOT is respectfully reminded that they will need to demonstrate the
avoidauce,imd,minimization of impacts to wetlands (and streams) to the maximum extent
practical. In accordance with the Environmental Management Commission's Rules { 15A NCAC
2H.0506(h)), mitigation will be required for impacts of greater than I acre to wetlands. In the
event that mitigation is required, the mitigation plan shall be designed to replace appropriate lost
functions and values. The NC Ecosystem Enhancement Program may be available for use as
wetland mitigation.
6. In accordance with the Environmental Management Commission's Rules {I 5A NCAC
2H.0506(h)), mitigation will be required for impacts of greater than 150 linear feet to any single
perennial stream. In the event that mitigation is required, the mitigation plan shall be designed to
replace appropriate lost functions and values. The NC Ecosystem Enhancement Program may be
available for use as stream mitigation.
7. Future documentation, including the 401 Water Quality Certification Application, shall continue
to include an itemized listing of the proposed wetland and stream impacts with corresponding
mapping.
8. NCDWQ is very concerned with sediment and erosion impacts that could result from this project.
NC DOT shall address these concerns by describing the potential impacts that may occur to the
aquatic environments and any mitigating factors that would reduce the impacts.
9. An analysis of cumulative and secondary impacts anticipated as a result of this project is required.
The type and detail of analysis shall conform to the NC Division of Water Quality Policy on the
assessment of secondary and cumulative impacts dated April 10, 2004.
10. NC DOT is respectfully reminded that all impacts, including but not limited to, bridging, fill,
excavation and clearing, and rip rap to jurisdictional wetlands, streams, and riparian buffers need
to be included in the final impact calculations. These impacts, in addition to any construction
impacts, temporary or otherwise, also need to be included as part of the 401 Water Quality
Certification Application.
11. Where streams must be crossed, NCDWQ prefers bridges be used in lieu of culverts. However,
we realize that economic considerations often require the use of culverts. Please be advised that
culverts shall be countersunk to allow unimpeded passage by fish and other aquatic organisms.
Moreover, in areas where high quality wetlands or streams are impacted, a bridge may prove
preferable. When applicable, DOT should not install the bridge bents in the creek, to the
maximum extent practicable.
12. Whenever possible, NCDWQ prefers spanning structures. Spanning structures usually do not
require work within the stream or grubbing of the streambanks and do not require stream channel
realignment. The horizontal and vertical clearances provided by bridges shall allow for human
and wildlife passage beneath the structure. Fish passage and navigation by canoeists and boaters
shall not be blocked. Bridge supports (bents) shall not be placed in the stream when possible.
13. Bridge deck drains shall not discharge directly into the stream. Stormwater shall be directed
across the bridge and pre-treated through site-appropriate means (grassed swales, pre-formed
scour holes, vegetated buffers, etc.) before entering the stream. Please refer to the most current
version of NCDWQ's Stormwater Best Management Practices.
14. Sediment and erosion control measures shall not be placed in wetlands or streams.
15. Borrow/waste areas shall avoid wetlands to the maximum extent practical. Impacts to wetlands
in borrow/waste areas will need to be presented in the 401 Water Quality Certification and could
precipitate compensatory mitigation.
16. The 401 Water Quality Certification application will need to specifically address the proposed
methods for Stormwater management. More specifically, stormwater shall not be permitted to
discharge directly into streams or surface waters.
17. If concrete is used during construction, a dry work area shall be maintained to prevent direct
contact between curing concrete and stream water. Water that inadvertently contacts uncured
concrete shall not be discharged to surface waters due to the potential for elevated pH and
possible aquatic life and fish kills.
18. If temporary access roads or detours are constructed, the site shall be graded to its preconstruction
contours and elevations. Disturbed areas shall be seeded or mulched to stabilize the soil and
appropriate native woody species shall be planted. When using temporary structures the area
shall be cleared but not grubbed. Clearing the area with chain saws, mowers, bush-hogs, or other
mechanized equipment and leaving the stumps and root mat intact allows the area to re-vegetate
naturally and minimizes soil disturbance.
19. Placement of culverts and other structures in waters, streams, and wetlands shall be placed below
the elevation of the streambed by one foot for all culverts with a diameter greater than 48 inches,
and 20 percent of the culvert diameter for culverts having a diameter less than 48 inches, to allow
low flow passage of water and aquatic life. Design and placement of culverts and other structures
including temporary erosion control measures shall not be conducted in a manner that may result
in dis-equilibrium of wetlands or streambeds or banks, adjacent to or upstream and down stream
of the above structures. The applicant is required to provide evidence that the equilibrium is being
maintained if requested in writing by NCD WQ. If this condition is unable to be met due to
bedrock or other limiting features encountered during construction, please contact NCDWQ for
guidance on how to proceed and to determine whether or not a permit modification will be
required.
20. If multiple pipes or barrels are required, they shall be designed to mimic natural stream cross
section as closely as possible including pipes or barrels at flood plain elevation, floodplain
benches, and/or sills may be required where appropriate. Widening the stream channel should be
avoided. Stream channel widening at the inlet or outlet end of structures typically decreases
water velocity causing sediment deposition that requires increased maintenance and disrupts
aquatic life passage.