20171650 Ver 1_B-5687 stormwater management plan_20171221

Hi�hwdy North Carolina Department of Transportation
Stoj-in�vater � `1
,,.,,,.�,,,� Highway Stormwater Program _;;
STORMWATER MANAGEMENT PLAN
(Version 2.07; Released October 2016) FOR NCDOT PROJECTS
WBS Element: 45641.1.1 TIP No.: B-5687 County(ies): Warren Page 1 of 1
General Project Information
WBS Element: 45641.1.1 TIP Number: B-5687 Project Type: Bridge Replacement Date: 8/22/2017
NCDOT Contact: Matthew Lauffer, PE Contractor / Designer: Trenton Cormier, PE
Address: NCDOT Hydraulics Unit Address: ICA Engineering, Inc.
1590 Mail Services Unit 5121 Kingdom Way, Suite 100
Raleigh, NC 27560 Raleigh, NC 27607
Phone: [phone] Phone: [phone]
Email: mslauffer ncdot. ov Email: trenton.cormier hdrinc.com
City/Town: Warrenton Count ies : Warren
River Basin(s): Cape Fear CAMA County? No
Wetlands within Project Limits? Yes
Pro'ect Description
Project Length (lin. miles orfeet): 0.15 Surrounding Land Use: Low Residential, Wooded
Proposed Project Existin Site
Project Built-Upon Area ac. ac. ac.
Typical Cross Section Description: Lickskillet Road (SR 1620): 2 paved lanes (total 20' wide), 4' shoulder on each side (7' Lickskillet Road (SR 1620): 2 paved lanes (total 20' wide), 4' shoulder on each side.
with guardrail).
Annual Avg Daily Traffic (veh/hr/day): Desi n/Future: 760 Year: 2025 Existin : 380 Year: 2011
General Project Narrative: The North Carolina Department of Transportation (NCDOT) has proposed to replace Warren County Bridge #43 on Lickskillet Road (SR 1620) over Shocco Creek. The existing
(Description of Minimization of Water structure is an eight span bridge (4@15'-0"; 2@15'-1.5"; 2@15'-4.5") and is a timber deck on I-Beams supported by timber caps on timber piles. The proposed structure is a
Quality Impacts) three span (1 @35' (21 "PCCS), 1@75' (24"PCCS), 1@25' (21 "PCCS)), with 4' deep caps. This structure has been designed to have as little environmental, wetland, and surface
water impacts as possible. 2:1 roadway fill slope will be used in the wetland areas to minimize wetland impacts. The permanent drainage easement (PDE) will be set to have as
little wetland impacts as possible.
To avoid direct discharge of bridge storm water into the receiving water, deck drains are not required for the proposed bridge. Storm water impacts to the stream have been
minimized by utilizing grated inlets and pipes to collect bridge storm water and use rip rap outlet protection at 13+65 LT to dissipate energy to provide a diffuse flow (non-erosive
sheet flow) in a wooded area. This diffuse flow will run for a distance of 12'+/- before entering the buffer. On the same southwest quadrant, an existing roadside ditch outlets at
11+50 LT with a non-erosive outlet velocity and sheet flows 160' before entering the buffer. At the southeast quadrant an existing roadside ditch has outlet at 12+30 RT and will
be turned out by the proposed fill slope. At the northeast quadrant there is an existing ditch that outlets at 18+82 RT. This ditch flows for 70'+/- before entering the wetland as
non-erosive sheet flow. At the northwest quadrant there is an existing ditch that outlets at 17+10 LT. This ditch will be retained and the proposed fill slope will be lined with toe
protection. The ditch outlets and will become a non-erosive sheet flow 150'+/- before entering the buffer. Due to the nature of low impact bridge replacement, the increases in
stormwater discharges (post vs pre condition) are insignificant and the existing ditches do not need to be modified. Therefore, additional stormwater measures are not required.
Waterbod Information
Surface Water Body (1): Shocco Creek NCDWR Stream Index No.: 28-79-22
NCDWR Surface Water Classification for Water Body Primary Classification: Class C
Supplemental Classification: Nutrient Sensitive Waters (NSW)
Other Stream Classification: None
Impairments: None
Aquatic T&E Species? No Comments:
NRTR Stream ID: Buffer Rules in Effect: Tar-Pamlico
Project Includes Bridge Spanning Water Body? Yes Deck Drains Discharge Over Buffer? No Dissipator Pads Provided in Buffer? No
Deck Drains Dischar e 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)