U-5951 US 17 interchange upgrades.pdf

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ROY COOPEK
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MICHA�L S. RLGAN
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Enviro��nientc�l LINUA CULYGPYGR
Qualit y hrlcrim Uireclnr
January 3, 2018
MEMORANI)UM
To: Brian I Iarding, NCDOT Division 3 llDC llesign Engineer
From: Joamie Steenhuis, NC Division of Water Resources, Wilming[on Regional Office.�
Subject: Scoping comments on proposed interchange upgrade improvements a[ [he US 17 Businass (Marine Blvd.)
and US l7 intersection in Onslow County, Sta[e Project Nu. WBS No. 45S70.L1, STIP U-5951.
Reference your correspondence dated December 20, 2017 in which you requested comtnents for the referenced
project. Preliminary analysis of Ihe project reveals lhe potenlial for multiple impacts [o sireams and jw�isdictional
wetlands in [he project area. More specifically, impacls to:
Stream Name River Basin S[ream Classifcation(s) Stream Index 303(d) Listing
Number
Sand Run Brancl� White Oak SC;NSW 19-10-1 N/A
Scales Creek White Oak SC;I I W, NSW 19-16-4 N/A
Dee Gull Creek White Oak SC;NSW 19-9-I N(A
Further investigatio��s at a liigher resolution should be under[aken [o verify the presence of other streams andJor
jurisdictional wetlands in the area Ln [he event that any jurisdic[ional areas are identified, [he Division of Water
Resources requests that NCDO'1' co��sider tlie following enviromnental issues for the proposed project:
Project Specific Comments:
Sandy Run Branch, Scales Creek and Deep Gully Creek are all classified as NSW waters of the State. The
NCD W R is very concemed with sediment �nd erosion impacts Ihat could result from lhis project. The
NCD W R recommends thal highly protective sedimenl and erosion conh'oI BMPs be implemented to reduce
the risk of' nutrient runoff to these Creeks. Additionally, to mee[ the requirements of NCDO'I"s NPDES
permit NCS0000250, [he NCUWR requests [ha[ road design plans provide lreatmen[ offhe storm water
runuff (hrough bes[ management practices as detailed in the mos[ recent version of the Norlla Cnrolinn
Depn��hiren� qf'!'rn��s�a•la�ion Stornnvu[er Ues� Mnnugemen! Prnctices Too(bo.r manual.
2. Review of the project reveals the presence of surface waters classified as HQW; High Quality Waters of the
State in [he project s[udy area. 'T'his is one of the highest classifications for waler quality.
3. Scales Creek is also designated as a PNA (Primary Nursery Area) by the Division of Marine Fisheries in
this area.
General Project Comments:
4. "I'he environn�enlal docwuen[ should provide a detailed end ilemized presenlalion of lhe proposed impac[s
to wetlands and s[reams wilh wrresponding mapping. If mi[igation is uecessa�y as required by I SA NCAC
2H.0506(h), il is preferable to present a conceptu�l (if not finalized) initiga�ion plan with the environmen[al
docwnentation. Appropriate miligation plans will be required prior to issuance of a 40I Water Quality
Certitication.
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5. Environmental impact statement alternatives shall consider design criteria that reduce the impacts to streams
and wetlands from storm water runoff. These altematives 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 the
North Caro[ina Deparhnent ofTransportation Stormwater Best Management Practices Tool box manual,
such as grassed swales, buf%r azeas, preformed scour holes, retention basins, etc.
6. After the selection of the preferred altemative 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 Emironmental
Management Commissiods Rules (15A NCAC 2H.0506[h]), mitigation will be required For impacts of
greater than 1 acre to wetlands. In the event that mitigation is required, the mitigation plan shall be designed
to replace appropriate lost functions and values. North Cazolina Division of Mitigation Services may be
available for assistance with wetland mitigation.
7. In accordance with the Environmental Management Commission's Rules (15A NCAC 2H.0506[h]),
mitigation will be required for impacts of greater than 150 linear 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 North Carolina Division of Mitigation Services may be available for assistance with stream
mitigation.
8. 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.
9. The NCDWR is very concemed with sediment and erosion impacts that could result from this project. The
NCDOT shall address these concems by describing the potential impacts that may occur to the aquatic
environments and any mitigating facrors that would reduce the impacts.
] 0. 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.
11. 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 ofthe 401 Water Quality Certification Application.
12. 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.
13. Whenever possible, the NCD WR prefers spanning structures. Spanning structures usually do not require
work within the sheam or grubbing of the sheambanks and do not require stream channel realignment. The
horizontal and vertical cleazances 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.
14. Bridge deck drains shall not discharge directly into the stream. Stormwater shall be directed across the bridge
and pre-heated through site-appropriate means (grassed swales, pre-formed scour holes, vegetated buffers, etc.)
before entering the sheam. To meet the requirements of NCDOT's NPDES permit NCS0000250, please refer
to the most recent version of the North Carolina Department of Transportation Stormwater Best Management
Practices Toolbox manual for approved measures.
15. Sediment and erosion control measures should not be placed in wetlands or streams.

16. Borrow/waste azeas should avoid weUands to the maximum extent practicaL Impacts [o wetlands in
borrow/waste areas will need to be presented in the 40l Water Quality Certification and could precipitate
compensatory mitigation.
17. 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.
18. Based on the basic information presented in the document, the magnitude of impacts to wetlands and streams
is not known. The project may require an Individual Permit (IP) or Nationwide (NW) depending on the
amount of impacts proposed. Final permit authorization will require the submittal of a formal application by
the NCDOT to the Corps of Engineers and corresponding 401 Water Quality Certification from the DWR.
Please be advised that a 401 Water Quality Certification requires satisfactory protection of water quality to
ensure that water qualiry standazds are met and no wetland or slream uses aze lost. Please be awaze that any
approval will be contingent on appropriate avoidance and minimization of wetla�d and stream impacts to the
maximum extent practical, the development of an acceptable stormwater management plan, and the indusion
of appropriate mitigation plans where appropriate.
19. If concrete is used during construction, a dry work area shall be maintained to prevent d'vect contact between
curing concrete and sheam 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.
20. 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 azea shall be cleazed 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 azea to re-vegetate naturally and minimizes soil disturbance.
2 L 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 geater 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 culveRs 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 upsfream 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 NCDWR.
IFthis condition is unable to be met due to bedrock or other limiting features encountered during conshuction,
please contact the NCDWR for guidance on how to proceed and to determine whether or not a permit
modificatian will be required.
22. 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 strucmres typically decreases water velocity causing sediment deposition that requires
increased maintenance and disrupts aquatic liFe passage.
23. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved
under General 401 Certification Number 3883/Nationwide Permit No. 6 for Survey Activities.
24. 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.
25. All work in or adjacent to 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.
26. While the use of National 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.
27. Heavy equipment should be operated from the bank rather than in sheam 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.
28. 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.
29. Riparian vegetation (native trees 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 construction.
Thank you for requesting our input at this time. The NCDOT is reminded that issuance of a 401 Water Quality
Certification requires [hat appropriate measures be instituted to ensure that water quality standards aze met and
designated uses are not degraded or lost. If you have any questions or require additional information, please contact
Joarme Steenhuis at (9l0) 796-7306 [e-mail].
Electronic copy only distribution:
Aliso� Nichols, AICP, RS&H Project Manager
Mason Hemdon, NCDOT Division 3 DEO
Brad Shaver, US Army Corps of Engineers, Wilmington Field Office
Cathy Brittingham, NC Division oFCoastal Management
Stephen Lane, NC Division of Coastal Management
Kristi Lynn Carpenter, NCDWR
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