20191153 Ver 1_Stormwater Management Plan from SEPI_20190829

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Highway Stormwater Program a
STORMWATER MANAGEMENT PLAN
(Version 2.08; Released April 2018) FOR NCDOT PROJECTS
WBS Element: 44361.1.1 TIP No.: U-5789 County(ies): Onslow Page 1 of 1
General Project Information
WBS Element:
44361.1.1 ITIP Number: U-5789 Project Type: Roadway Widening Date: 8/26/2019
NCDOT Contact:
Eric MurrayContractor
/ Designer:
SEPI Engineering & Construction
Address:
NCDOT Division 3 DDC
Address:
1 Glenwood Avenue
5501 Barbados Blvd.
Suite 600
Castle Hayne, NC 28429
Raleigh, NC 27603
Phone:
910-341-2000
Phone:
919-747-5839
Email:
ecmurra ncdot. ov
Email:
[e-mail]
City/Town:
Jacksonville, NC
County(ies):
Onslow
River Basin(s):
White Oak
CAMA County?
Yes
Wetlands within Project Limits?
Yes
Project Description
Project Length (lin. miles or feet):
1.15 Surrounding Land Use: Urban. Fully Built -Out. Mostly Commercial Development
Proposed Project
Existing Site
Project Built -Upon Area (ac.)
14.1 ac.
13.2 ac.
Typical Cross Section Description:
Proposed Typical section approximates the existing (-L-). Improvements consist of the
Western Blvd (-L-), 4-lane, 2-way traffic with 46-ft depressed grass median. Existing
addition / lengthening of turn lanes and the improvement proposed turning movements at
travel lanes are +/- 12-ft wide. 2-ft paved shoulder both sides. Typical section widens
existing intersection locations. Widening for turn lane storage is proposed along
at multiple intersection locations in order to accommodate turn lanes. Gateway North
Gateway North (-Y1-) and Jacksonville Parkway (-Y-).
Y1-) and Jacksonville Parkway (-Y-) are both 4-lane, 2-way traffic. Gateway North has
no median and Jacksonville Parkway has some raised concrete median.
Annual Avg Daily Traffic (veh/hr/day):
Design/Future: 41,500 Year: 2019
Existing: 52,000 Year: 2040
General Project Narrative:
For most of the project, fill slopes were designed at a 3:1 foot elevation ratio. For site 2, the slopes were steepened to a 2:1 foot elevation ratio, which avoided impacts to the
(Description of Minimization of Water
perennial stream near this site and reduced wetland impacts from 0.030 acres to 0.011 acres.
Quality Impacts)
The new drainage pipe will be buried approximately 1 foot below the natural stream bed, which will facilitate conveyance of aquatic organisms and help prevent scour holes. The
current drainage pipe shows evidence of a perched culvert, which is likely currently preventing the movements of most aquatic organisms.
Riprap at the northwestern outlet of the drainage pipe will not be placed in the stream channel to avoid permanent impacts to the stream. The riprap and GeoTextile fabric will
also minimize sedimentation of the stream.
A headwall will be constructed to avoid permanent impacts to the portion of the unnamed perennial stream that is southeast of Gateway Drive North. This headwall will also
prevent impacts to the surrounding wetland via fill slopes.
A silt fence will be placed along the limits of disturbance to discourage sedimentation of the stream. Appropriate sediment and erosion BMPs have been developed for the
project.
Waterbody Information
Surface Water Body (1):
Mill Creek NCDWR Stream Index No.: 19-9
NCDWR Surface Water Classification for Water Body
Primary Classification:
Class SC
Supplemental Classification:
Nutrient Sensitive Waters (NSW)
Other Stream Classification:
Impairments:
mercury H
Aquatic T&E Species?
No Comments: No habitat present
NRTR Stream ID:
Buffer Rules in Effect: N/A
Project Includes Bridge Spanning Water Body-7
No
I Deck Drains Discharge Over Buffer? I N/A
Dissipator Pads Provided in Buffer? N/A
Deck Drains Discharge Over Water Body?
I N/A
(If yes, provide justification in the General Project Narrative)
(If yes, describe in the General Project Narrative; if no, justify in the
General Project Narrative)
L. (If yes, provide justification in the General Project Narrative) I