SW6240903_Stormwater Narrative_20241002

5245 Red Hill Church Rd
FLEET TEMPLE Coats, NC 27521
ENGINEERING 910.658.2446
[e-mail]
PLLC Firm License P-2357
NC 42 Mini Storage
Buckhorn Township, Harnett County
07.31.2023
PROJECT NARRATIVE
Project & Site Description
The purpose of this project is to develop a 11.9 acre mini storage site. The property is
existing agricultural(row crops) and woodlands. Existing topography drains to the
north and south at slopes of approximately 3% -10%to Buckhorn Creek (north) and to
Avents Creek (south). A portion of the property is located within a High Quality
Watershed. No wetlands are present on the Site. The Site is limited to maximum 90%
impervious area upon build-out (High Density Development).
Adjacent Property
The land uses in the surrounding areas are residential and agricultural.
Soils
The soils in this project consist primarily of Pf (Pocalla loamy sand, 0 to 6% slopes). Pf
is categorized as well drained, permeability is moderately rapid, and is well 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.
Stormwater runoff from the new development flows primarily to the north and south
to two different streams (noted above). During construction, runoff will be conveyed
to temporary skimmer basins via sheet flow and diversion berms. The basins will be
converted into a proposed wet detention pond and a proposed infiltration basin upon
completion of site development. The wet detention pond and infiltration basin are
designed per NCDEQ Standards. Proposed overall impervious percentage for design
is 90.0% impervious. Runoff will flow into forebays for the wet detention pond via
grassed swales. The forebay will empty via a spillway into the main pond. The Pond is
constructed to draw down within the prescribed timeline of two (2) to five (5) days.
The Pond will release excess volume via an emergency spillway. The emergency
spillway is designed for a 100 yr storm. Infiltration basin is designed per NCDEQ
requirements - a soil analysis has been completed by a licensed soils scientist for the
infiltration basin.