HomeMy WebLinkAboutU-5731 Scoping letter� �
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MICHAELS.REGAN
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Envir'orortental S. JAY ZIMMERMAN
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August23,2017
MEMORANDUM
"I'o: Charles R. Cox, PC, RS&f I Project M�nager
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From: Jo�m�e S[eenhuis NC Division of W�ter Resow'ces, W ilmington Regioual Oftice \ ��
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Subject Scoping comments on proposed improvcmen[s lo the intcrsec[iou of US 74 and US 17/US 421 in New
Hanover County, State Project No. W BS No. 54022.1. I,'I'IP U-5731.
Referencc your correspondence deted August 18, 2017 in which you requested comments for thc referenced projec[.
Preliminary �nalysis ofthe project reveals the potential for multiple im�acts to stre�ms and jw�isdiclional weNands
in the project m�ca. More specifically, impacts ro:
Siream Nnme River 6asin Stream Classification(s) Slream Index 303(d) Listing
Number
NG Ce �e �eTr River C� e Pear C;Sw 18-(63) N/A
Pmther investigations at a higher resolution shuuld bc undcrtakcn to verify the presence of other slreams and/or
jurisdictional wetlands in the area. In Ihe evenl that anyjurisdiciional areas are ideulilied, Ihe Division of Wa[er
Resom�ces requesls thTt NCDO'C consider the following envirounrenlal issues Cor Ihe proposed project
Gencral Projec[ Conunents:
7�he enviroumental document shoulcl provide �i detniled and i[emized presentatiou of the proposed impacts to
wetlands and slre.�ms witl� corresponding mapping. IEmitigation is necessary as required by ISA NCAC
2H.0506(h), il is preCerable to preseut a conceptual (it not linalized) mitigation plau with the environmen[al
documenlation. Appropriate milig�tion plans will be required prior to issuance of 2 401 Waler Quality
Certitica[ion.
2. Environmental impact stltement al[erna[ives sh�ll consider design criteri� lhnl reduce the impacts to streams
and wetlands from storm water runofE These al[ernalives sh�ll include ro�d designs that tjllow for tre�imenl
of Ihe storm water runoCf through besl managemen[ practices as detailed in [he mosL recent version of the
Na�th Cm�olina Depm�tmerrl oJTrans��oiTnlron Slorunvn(e�• Bes[ Marrngemen( Prantices Too[ bos manual,
such as grassecl swales, bufCer areas, prefunned scour holes, retention basins, etc.
After the selec[ion of the preferred alterna[ive and prior to an issu�nce of the d01 Water Qu�lity Ce�tific�tion,
[he NCllO'f is respectfully remiudcd th�t �hcy will nced to demonstrate lhc avoid�ncc and minimization oF
imp.ic[s to wetlands (and sVeams) to tlie m�xinuun exten[ practical. In aeeordance with the Environmental
Mnnagemen[ Commission's Rules (ISA NCAC 2H.0506[h]), mitiga[ion will be required for impac�s of
greater thun I ncre lo wetlands. ln the even[ �liat mitigation is required, the mi[ig�[ion pl�n sh�ll be designed
to repince nppropriate lost functions and values. Nor[h Carolina Division of Mitigation Services may be
availnble for assist�nce with wetland mitig�tion.
`� No[hing Compares'--._
Statc o(Norlh Carolina � Iimironincnfal Quality
1617 Mnil Scrvicc Cenlzr � Ralcigh, �brth Carolina 27699-1GI7
4. In accordance with the Emironmental Management Commission's Rules ( l5A NCAC 2H.0506[hj),
mitigation will be required for impacts of greater than 150 linear feet to any perennial stream. In the event
that mitigation is required, the mitigation plan shall be designed to replace appropriate lost functions and
values. The North Carolina Division of Mitigation Services may be available for assistance with stream
mitigation.
5. 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.
6. The NCDWR is very concerned with sediment and erosion impacts that cauld result from 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.
7. 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 l0, 2004.
8. The NCDOT 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 Qualiry Certification Application.
9. Where streams must be crossed, the NCDWR 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 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 in the creek, to the maximum extent practicable.
l0. Whenever possible, the NCDWR 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)
should not be placed in the sheam when possible.
1 I. 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. To meet the requirements of NCDOT's NPDES permit NCS0000250, please refer
to the most recent version of the North Carolrna Department of Transporfatron Stormwater Best Man�gemen[
Practices Toolboz manual for approved measures.
12. Sediment and erosion control measures should not be placed in wetlands or streams.
13. Borrow/waste areas should 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.
l4. 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.
I5. Based on the information presented in the document, the potential magnitude of impacts to wetlands and
streams may require an Individual Permit (IP) application to the Corps of Engineers and corresponding 40l
Water Quality Certificatioa Please be advised that a 401 Water Quality Cer[ification requires satisfactory
protection of water quality to ensure that water quality standards are met and no wetland or stream uses are
lost. 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 contingent 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.
16. If concrete is used during consh-uction, 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 Iife and fish kills.
17. 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.
18. Unless otherwise authorized, placement of culverts and other structures in waters and streams 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 strucmres 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 structures. The applicant is
required to provide evidence that the equilibrium is being maintained if requested in writing by the NCDW R.
If this condition is unable to be met due to bedrock or other limiting features encountered during construction,
please contact the NCDWR for guidance on how to proceed and to determine whether or not a permit
modification will be required.
l9. If multiple pipes or barrels are required, they shall be designed to mimic natural stream cross section as
closely as possible inc(uding 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.
20. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved
under Geceral 40l CeRification Number 3883/Nationwide Permit No. 6 for Survey Activities.
21. Sediment and erosion control measures sufficient to protect water resources must be implemented and
maintained in accordance with the most recent version of North Carolina Sediment and Erosion Control
Planning and Design Manual and the most recent version of NCS000250.
22. All work in or adjacent ro stream waters 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.
23. While the use ofNational Wetland Inventory (NWI) maps, NC Coastal Region Evaluation of Wetland
Significance (NGCREWS) maps and soil survey maps are useful tools, their inherent inaccuracies require
that qualified personnel perform onsite wetland delineations prior to permit approval.
24. Heavy equipment should be operated from the bank rather than in stream channels 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.
25. 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 structures should be properly designed, sized and installed.
26. Riparian vegetation (native hees and shrubs) shall be preserved to the maximum extent possible. Riparian
vegetation must be reestablished within the construction limits of the project by the end of the growing season
following completion of constructian.
Thank you for requesting our input at this time. The NCDOT is reminded that issuance of a 401 Water Quality
Certification requires that appropriate measures be instituted to ensure that water qualiry standards are met and
designated uses are not degraded or lost. If you have any questions or require additional information, please contact
Joanne Steenhuis at (910) 796-7306 orjoanne.steenhuis@ncdenr.gov.
Electronic copy only distribution:
Brad Shaver, US Army Corps of Engineers, Wilmington Field Office
Mason Herndon, NC DOT Division 3 DEO
Brian Harding, NC DOT Division 3 DDC Design Engineer
Cathy Brittingham, NC Division of Coastal Management
Kristi Lynn Carpenter, NCDWR
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