HomeMy WebLinkAboutSW6230604_Stormwater Narrative_20230629 5245 Red Hill Church Rd
_1 1-1 FLEET TEMPLE Coats, NC27521
ENGINEERING 910.658.2446
fleet@ftempleengineering.com
PLLC Firm License P-2357
Fox Field Farms
Upper Little River Township, Harnett County
06.06.2023
PROJECT NARRATIVE
Project & Site Description
The purpose of this project is to develop a 94.1 acre residential subdivision. The
property is existing farmland and woodland. Existing topography drains to the south
at slopes of approximately 1% - 30% to an un-named tributary Upper Little River. No
wetlands exist on the property. The Site is limited to maximum 24% impervious area
upon build-out (Low Density Development).
Adjacent Property
The land uses in the surrounding areas are residential and agricultural.
Soils
The soils in this project consist of Bb (Bibb loam, frequently flooded), BnB (Blaney
loamy sand, 2 to 8% slopes), DoA (Dothan loamy sand, 0 to 2% slopes), DoB (Dothan
loamy sand, 2 to 6% slopes), LnD (Lillington very gravelly sandy loam, 8 to 15% slopes),
VeD (Vaucluse gravelly loamy sand, 8 to 15%slopes), and VeE (Vaucluse gravelly loamy
sand, 15 to 25% slopes)
Bb is categorized as poorly drained, moderately permeable, and is poorly suited to
most urban and recreational uses. BnB is categorized as well drained, moderately
slowly permeable, and is moderately suited to most urban and recreational uses. DoA
is categorized as well drained, moderately to moderately slowly permeable, and is
moderately suited to most urban and recreational uses. DoB is categorized as well
drained, moderately to moderately slowly permeable, and is moderately suited to
most urban and recreational uses. LnD is categorized as well drained, moderately
permeable, and is poorly suited to most urban and recreational uses. VeD is
categorized as well drained, moderately slowly permeable, and is moderately suited
to most urban and recreational uses. VeE is categorized as well drained, moderately
to moderately slowly permeable, and is poorly suited to most urban and recreational
uses.
Planned Stormwater Management, Erosion and Sediment Control
As shown on the Erosion Control Plan the project will be controlled and stabilized with
diversion berms, silt fence, rock check dams, and temporary skimmer basins with
baffles. Diversion berms will be constructed from topsoil graded from the site and will
be backed with silt fence where needed. All measures will be constructed and
maintained to NCDEQ & Harnett County standards and requirements.
After erosion control measures are removed. Surface waters from the roadway areas
will drain via grassed roadside ditches to owner maintained grassy swales which will
convey the runoff from the property. Impervious areas on some portions of the lots
will surface drain through the grassed yard areas over the natural contours of the Site.
Project impervious percentage is limited to 24%. Proposed impervious limits as
follows:
IMPERVIOUS AREA CALCULATIONS:
TRACT AREA: 4,100,801 SF
IMPERVIOUS AREA ALLOWED: 24% MAX (LOW DENSITY)
4,100,801 SF X 0.24=984,192 SF MAXIMUM ALLOWABLE IMPERVIOUS
IMPERVIOUS AREA BY DESIGN
120,174 SF ASPHALT
825,000 SF(11,000 SF/LOT MAX IMPERVIOUS X 75 LOTS)
945,174 SF TOTAL IMPERVIOUS BY DESIGN (23.1%)