HomeMy WebLinkAboutR-5885 scoping letter Mar 19-001.pdfROY COOPER
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Envfrortmenfal Quafliy
March 4, 2019
MEMORANDUM
To:
From:
Kris[a Kimmel, PE, NCDOT Division 3, DDC Engineer-Advanced ��n
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Joanne Steenhuis, NC Division of Water Resources, Wilmington Regional Oftice U
Subject: Scoping comments on proposed construction of a superstreetlsuperstreet intersection along the NC 24
corridor from Belgrade-Swansboro Road (SR 1434) to Front Street in Onslow county, STIP No. R-SS85.
Further investigations at a higher resolution should be undertaken to verify the presence of other sheams and/or
jurisdictional wetlands in the area. In the event that anyjurisdictional areas are identified, the Division of Water
Resources requests that NCDOT consider the following environmental issues for the proposed project:
Projec[ Specific Comments:
7'o meet the requiretnents of NCDOT's NPDES permit NCS000250, the road design plans shall provide
treatment of the stonnwater runoff through BMPs as de[ailed in the tnost recent version of the North Carolina
Depar[men[ of Transportation Storrnwater Best Management Practices Toolbox manuaL The BMPs should be
selected and designed to [he MEPnto reduce impacts of the target pollutants of concem (POCs) for the receiving
waters.
2. Review of [he projec[ reveals the presence of surface waters classified as SA; High Quality Waters of the State in
the project study area. 7'his is one of the highest classifications for water quality. The NCDWR is concemed
with any impacts that may occur to streams with this classification. It is preferred that Ntese resources be
avoided if at all possible. lf it is not possible to avoid these resources, the impacts should be minimized to the
greatest extent possible. Given the potential for impacts to these resources during [he project implementation,
[he NCDWR requests that the NCDOT adhere to North Carolina regulations entitled "Design Standards in
Sensitive Watersheds° ( I SA NCAC 04B .0124) throughout design and construc[ion of the project.
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Reference your correspondence dated February 25, 2019 in which you requested comments for the referenced project.
Preliminary analysis of the project reveals the potential for multiple impacts to streams and jurisdictional wetlands in
the project area. More specifically, impacts to:
General Project Comments:
3. The environmental document should provide a detailed and itemized presentation of the proposed 'unpacts to
wetlands and streatns with corcesponding mapping. If mitigation is necessary as requ'ved by l5A NCAC
2H.0506(h), it is preferable to present a conceptual (if not finalized) mitigation plan with the environmental
documentation. Appropriate mi[igation plans will be required prior to issuance of a 40l Water Quality
Certification.
4. Enviromnental impact statement altematives shall consider design criteria that reduce the impacts to sheams and
wedands from storm water runof£ These alternatives shall include road designs that allow for treatment of the
storm water runoff through BMPs as detailed in the most recent version of the North Caro[ina Department of
Transporta[ion Stormwater Best Management Practices Tool box manual, such as grassed swales, buffer areas,
preformed scour holes, retention basins, etc.
5. After 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 avoidance and minimization of impacts
to wetlands (and streams) to the maximum extent practical. In accordance with the Environmental Management
Commissiods Rules (15A NCAC 2H.0506[h]), mitigation will be required for impacts of greater than L acre to
wetlands. In the event that mitigation is required, the mitigation plan shall be designed to replace appropriate
lost functions and values. North Carolina Division of Mitigation Services may be available for assistance with
wetland mitigation.
6. In accordance with the Environmental Management Commission's Rules (15A NCAC 2H.0506[h]), mitigation
will be required for impacts of greater than 300 lineaz feet to any perennial stream [n the event that mitigation is
required, the mitigation plan shall be designed to replace appropriate lost functions and values. The NoRh
Carolina Division of Mitigation Services may be available for assistance with 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. The NCDWR is very concerned with sediment and erosion impacts that could result &om this project. The
NCDOT 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 Resource Policy on the assessment of secondary and
cumulative impacts dated April 10, 2004.
] 0. The NCDOT is respec[fully 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.
I I. Where streams must be crossed, the NCDWR prefers bridges be used in lieu of culverts. However, we realize
[hat economic considerations often require the use of culverts. Please be advised that culverts should 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, the NCDOT should
not install the bridge bents i� the creek, to the maximum extent practicable.
12. Whenever possible, the NCDWR prefers sparming structures. Spanning structures usually do not require work
within [he stream or grubbing of the streambanks and do not require stream channel realigmnent 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) should not be
placed in the stream when possible.
13. Bridge deck drains shall not discharge direc[ly into the stream. Stormwater shall be directed across the bridge and
pre-treated [hrouglt site-appropriate means (grassed swales, pre-fonned scour holes, vegetated buffers, etc J before
entering the stream. To meet the requirements of NCDOT's NPDES permit NC5000250, please refer to the most
recent version of the North Caro[ina Department of Transportatron Stormwater Best Management Practices
Toolbox manual for approved measures.
14. Sediment and erosion control measures should not be placed in wetlands ar streams.
15. Borrow/waste areas should avoid wetlands to the maximum extent practical. hnpacts to wetlands in
borrow/waste areas will need to be presented in the 40l Water Quality Certification and could precipitate
compensatory mitigation.
l6. The 401 Water Quality Certification application will need to specifically address the proposed methods for
stonnwater management. More specifically, stonnwater shall not be permitted to discharge directly into streams
or surface waters. To meet the requirements of NCDOT's NPDES permi[ NCS000250, please refer to the most
recent version of the North Carolina Department ofTransportation Stormwater Best Managemen[ Practices
Toolbox manual for approved measures.
17. The DWR cannot comment on pennit requirements with the limited information provided. Detailed field
delineation is required to detennine the presence or absence ofjurisdictional resources within the project limits.
[n addition, NCDOT must provide an estimate to any resources located within the construction limits of the
project area before we can specifically comment on NCDWR permit eligibility. Final permit authorization will
require the submittal of a formal application by the NCDOT and written concurrence from the NCDWR. Please
be aware that any approval will be wntingent on appropriate avoidance and minimization of wetland and stream
impacts to the maximum extent practical, the development of an acceptable stormwater management plan, and
the inclusion of appropriate mitigation plans where appropriate.
18. If concrete is used during construction, a dry work area shall be maintained to prevent direct contact between
curing concrete and s[ream water. Water that inadvertently contacts uncured concrete shall not be dischazged to
surface waters due to the potential for elevated pH and possible aquatic life and fish kills. Concrete shall be
handled in accordance with the NPDES Construction General Permit NCGO10000.
l9. 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.
20. Unless otherwise authorized, placement of culverts and other shuctures in waters and streams shall be placed
below the elevation of the streambed by one foot for all culverts with a diameter greater [han 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 wlverts 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 downstream of the above shuctures. 'Phe applicant is required to provide
evidence [hat the equilibrium is being maintained if requested in writing by the NCDWR. lf this condition is
unable to be met due to bedrock or o[her litni[ing features encountered during construction, please contac[ the
NCDWR for guidance on how to proceed and to detennine whe[her or not a pennit modification will be
required.
2 L 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, tloodplain benches, and/or sills may be required
where appropriate. Widening the stream channel should be avoided. Sheam 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.
22. If foundation test borings are necessary; it shall be noted i� the document. Geotechnical work is approved under
Genera1401 Certification Number 4085/Nationwide Permit No. 6 for Survey Activities.
23. Sediment and erosion control measures sufficient to protect water resources must be implemented and
maintained in accordance with [he most recent version of North Carolina Sediment and Erosion Control Planning
and Design Manual and the most recent version of NCS000250.
24. All work in or adjacent to stream wa[ers shall be conducted in a dry work area. Approved BMP measures from
the most current version of the NCDOT Construction and Maintenance Activities manual such as sandbags, rock
berms, cofferdams and other diversion structures shall be used to prevent excavation in flowing water.
25. While the use of National Wetland lnventory (NWI) maps, NC Coastal Region Evaluation of Wetland
Significance (NGCREWS) maps and soil survey maps are useful tools, their inherent inaccuracies require tha[
qualified personnel perform onsite wetland delineations prior to permit approval.
26. Heavy equipment should be operated &om the bank rather than in stream charmels in order to minimize
sedimentation and reduce the likelihood of introducing other pollutants into streams. This equipment shall be
inspected daily and maintained to prevent contamination of surface waters from leaking fuels, lubricants,
hydraulic fluids, or other toxic materials.
27. Riprap shall not be placed in the active thalweg channel or placed in the streambed in a manner that precludes
aquatic life passage. Bioengineering boulders or shvctures should be properly designed, sized and installed.
28. Riparian vegetation (native trees and shrubs) shall be preserved to the maximum extent possible. Riparian
vegetation must be reestablished within the conshuction limits of the project by the end of the growing season
following completion of construction.
Thank you for requesting our input at this time. The NCDOT is reminded that issuance of a 401 Water Quality
Certification requ'ves that appropriate measures be instituted to ensure that water quality standards are met and
designa[ad uses are not degraded or los[. If you have a��y questions or require additional information, please contact
Joanne Steenhuis at (910) 796J306 orjoanne.steenhuis@ncdenr.gov.
Electronic copy only distribution:
Mason Herndon, NC DOT Division 3 Environmental Supervisor
Brad Shaver, US Army Corps of Engineers, Wilmington Field Office
Cathy Brittingham, NC Division of Coas[al Management
Stephen Lane, NC Division of Coastal Management
Kristi Lynn Carpenter, NCDWR
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