20190328 Ver 1_17BP.6.R.75_HYD_SMPv2.07_(20180104)_20190307

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STORMWATER MANAGEMENT PLAN ---
(Version 2.07; Released October 2016) FOR NCDOT PROJECTS
WBS Element: 17BP.6.R.75 TIP No.: SF-250141 County(ies): Cumberland Page 1 of 2
General Project Information
WBS Element: 17BP.6.R.75 TIP Number: SF-250141 Project Type: Bridge Replacement Date: 2/26/2019
NCDOT Contact: Christy Wright Huff, P.E. Contractor / Designer: Atkins
Address: NCDOT Hydraulics Unit Address: 1616 E Millbrook Road, Suite 160
1020 Bridge Ridge Drive Raleigh, NC 7609
Raleigh, NC 27610
Phone: [phone] Phone: [phone]
Email: qcail(cc�ncdot.qov Email: kenneth.hunu(cr�.atkinsqlobal.com
City/Town: Unincorporated County(ies): Cumberland
River Basin(s): Cape Fear CAMA County? No
Wetlands within Project Limits? No
Project Description
Project Length (lin. miles or feet): 0.062 mi Surrounding Land Use: Rural, Agricultural
Proposed Project Existing Site
Project Built-Upon Area ac. 0.2 ac. 0.1 ac.
Typical Cross Section Description: 2-lanes at 11' each with +/-2-4' paved shoulders 2-lanes at 9' each with +/-4' unpaved shoulders
Annual Avg Daily Traffic (veh/hr/day): Design/Future: 330 Year: 2019 Existing: 330 Year: 2004
General Project Narrative: This project replaces existing BR#250141, 2 Span @ 35.34' (1@17.84', 1@17.5'), Reinforced Concrete Floor on Timber Joists, timber caps, piles and bulkheads, with a 1@ 34'
(Description of Minimization of Water 9" x 8'-9" Aluminum Box Culvert, with headwalls, sills and baffles. There is a slight increase in the impervious area of the project, however, there is no real increase in drainage
Quality Impacts) due to the increased impervious area. Runoff from the roadway impervious surface will be captured in special cut ditches and discharged at the existing ditch outfall points. The
discharge velocity in the ditches is non-erosive with a range between 2-4 fps.
Waterbody Information
Surface Water Body (1): South River Tributary I NCDWR Stream Index No.: 18-68-12
NCDWR Surface Water Classification for Water Body Primary Classification: Class C
Supplemental Classification: Swamp Waters Sw
Other Stream Classification: None
Impairments: None
Aquatic T8�E Species? No Comments:
NRTR Stream ID: Buffer Rules in Effect: N/A
Project Includes Bridge Spanning Water Body? No Deck Drains Discharge Over Buffer? N/A Dissipator Pads Provided in Buffer? N/A
Deck Drains Discharge Over Water Body? No (If yes, provide justification in the General Project Narrative) (If yes, describe in the General Project Narrative; if no, justify in the
(If yes, provide justification in the General Project Narrative) General Project Narrative)

HighWay North Carolina Department of Transportation "���°,�
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� - - - ����` Highway Stormwater Program �
STORMWATER MANAGEMENT PLAN --
(Version 2.07; Released October 2016) FOR NCDOT PROJECTS
WBS Element: 17BP.6.R.75 TIP No.: SF-250141 Count ies : Cumberland Pa e 2 of 2
Bridge to Culvert Avoidance and Minimization
Proposed Structure Summary
Sheet No. 8� Station Sheet No.: 4 Station: 12+70.50 -L- Number of Barrels: 1
Drainage Area (ac or sq mi): 2.31 sq miles Barrel Width/Diameter (ft): 34' 9"
Surface Water Body: 1 South River Tributa I Barrel Hei ht ft : 8' 9"
Culvert T e: Aluminum Box Culvert Culvert Len th ft 46'
Avoidance and Minimization Efforts: Special stilling basins will be used as needed, along with impervious dikes for temporary diversion of flow.
(Bridge to Culvert)
Stream Slope Fish and/or Aquatic Life Passage
Existing Average Stream Slope (%): 0.30 % Existing Low Flow Channel Dimensions
Proposed Culvert Slope (°/a): 0.00 % in the Stream:
Culvert Burial
Proposed Culvert Burial Depth (ft):
Existing Streambed Material: Silt Proposed Low Flow Dimensions
Through the Culvert:
Proposed Sills/Baffles: 1' sill backfilled with native material
Existing Low Flow Velocities in the
Stream (ft/s):
ropose ow ow e oci ies roug
the Culvert (ft/s):
Alternating Low Flow Sills/Baffles:
Culvert/Stream Alignment
Stream Patterns Upstream and Downstream Immediately upstream of the structure, the stream pattern is relatively straight which increases the likelihood of scour. Downstream there is more
of the Culvert that Could Affect Fish meandering so this should not affect fish passage or bank stability.
Passage and Bank Stability:
Bed Forms Impacted by Culvert (riffles, None
pools, glides, etc.):
Low Flow Floodplain Bench Required? No
(provide justification)
Bends at Inlet/Outlet? No
(describe culvert alignment with stream)
Stream Realignment Necessary? (provide No
justification)
Bank Stabilization: Class I Rip Rap is proposed at the inlet and outlet
Outlet Velocities
Natural Stream Channel 2-yr Velocity (ft/s): 1.4 Natural Stream Channel 10-yr Velocity (ft/s): 1.8
Proposed Culvert 2-yr Outlet Velocity (ft/s): 1.4 Proposed Culvert 10-yr Outlet Velocity (ft/s): 2.3
Roadway Geometric Considerations
Evaluate/Describe Roadway Geometric Constraints: