SW6220904_Stormwater Narrative_20221102

Hidden Vallev Subdivision Storm Water Narrative
The site is currently undeveloped. The site is being developed as a single family
residential development. The site drains to Buffalo Creek past the property boundaries
on the eastern side of the parcel.
The site meets the qualifications of a low density development. The average density for
the development is 1.7 units/acre compared to the maximum of 2 units/acre to satisfy
the requirements set forth by NCDEQ. The roads within the development will convey
storm water via curb and gutter to curb inlets. The curb inlets have a short section of
pipe that conveys the storm water through a grassed swale. The Hoke County ordinance
requires the streets to have concrete curb and gutter. This storm system terminates at
grassed swales which ultimately discharge into the swales and eventually has over land
flow to Buffalo Creek. The swales provide flow velocities less than the allowable
velocities with the exception of Ditch #1 and #10. These ditches will be reinforced with a
permanent erosion control matting and will have permanent check dams to reduce flow
velocities and encourage infiltration. Ditch #10 also exceeds the allowable 5%
longitudinal slope as a result of existing topography and limitations resulting from the
orientation of proposed buildable lots. The roads in the subdivision are designed in
accordance with NCDCT.
Based on our study and review of the NCDEQ BMP manual and NC Session Law 2006-
246 Section 9 paragraph c, Hidden Valley Subdivision meets and/or exceeds the
requirements and intent for low density development.
409 Chicago Drive. Suite 112, rayettevi I le. NC 28306
office 1 910-426-6777 fax [phone]
On time, every time. I www.4Dsitesolut!ons.com