SW6191201_Responce to Comments_20200210

Subject: Request for Additional Information - COMMENT RESPONSE
Stormwater Permit No. SW6191201
Lynn Ridge Subdivision
Harnett County
1. As designed, the project does not meet all of the requirements for a low -density project
(Section II, 2). Per 15A NCAC 02H .1003 (2)(c), "Stormwater that cannot be released as
dispersed flow shall be transported by vegetated conveyance." This rule allows for a
minimal amount of non -vegetated conveyances for unavoidable situations where water
needs to be piped under driveways and/or roadways. The proposed pipes are avoidable
(Aside from the propose pipe to allow the existing stream to pass under road "A"). Please
remove the avoidable non -vegetated conveyance from the project or provide a revised
application and the required items for a high -density submission.
STREET CROSS SECTION IS CURB & GUTTER WITH SIDEWALKS ON BOTH
SIDES OF ROADS. PIPES ARE STUBBED UNDERNEATH SIDEWALKS AS NEEDED. CB
& PIPE AT LOT 22/23 HAS BEEN CHENGED TO A CONCRETE FLUME & SWALE
COMBINATION.
2. Since the applicant is the property owner, Section III, 2 a & b are not required.
APPLICATION REVISED
3. Please include any surface water that exists within the property boundary in Section IV,
6. If there are surface waters within the property boundary but the total amount is less
than 0.01 acres, please indicate that the amount of surface waters is "< 0.01 acres" and
treat this value as zero for calculation purposes. Please also recalculate Section IV, 7 & 8
as needed. REVISED
4. Please provide an original, signed copy of the low -density supplement form (Section V
and Section VI, 3). ENCLOSED
5. Please provide an original, signed copy of the deed restriction form (Section VI, 2).
ENCLOSED
6. Please provide calculations showing how the 10-year flow (Q10) and velocity (V actual)
were calculated for the proposed curb outlet swales (Section VI, 7). ENCLOSED
7. Please show the stream buffer for the stream located east of the project area and west of
Lipscomb Road (Section VI, 8p). JD WAS EVALUATED BY A LICENSED SOIL SCIENTIST
AND INDICATED NO JURISDICTIONAL STREAM BUFFER IN THIS AREA SUBJECT
TO USACE VERIFICATION (USACE VERIFICATION IS NOT COMPLETED YET)
8. Please provide a soils report showing the SHWT elevation for the areas of the proposed
curb outlet swales (Section VI, 9). SOILS REPORT ENCLOSED. LOCATIONS SHOWN ON
S-4
9. Please replace the text "xxxxxx square feet" with the proposed square footage per lot on
the deed restriction form (Section VII). Please also add the stormwater permit number to
this form and have it re -signed and re -notarized. REVISED TO 2,457SF/LOT
10. Since the applicant is the property owner, Section IX is not needed. With your
permission, I will place a large red "X" though this section on the signed original copy. If
this is unsatisfactory to you, please provide a revised original application.
REVISED APPLICATION ENCLOSED

11. Please address the following on the Low Density Supplement Form:
a. 77 lots with a BUA of 2,478 sf per lot yields a total of 190,806 sf, not 190,865 sf.
Please revise the application and supplement to reflect this. BUA HAS BEEN REVISED
b. Please label the swales on the plans so that the information in the Low Density
Supplement Form can be verified. LABELS ADDED
c. Section IV, j - The maximum allowable discharge velocity for a swale
discharging into a wetland is 2.0 fps. Swales 3 and 5 discharge at a rate of 2.2 fps
into the wetlands, please revise. SWALES REVISED
d. Section IV, n - Please ensure that all swales are at least 100 feet in length.
LENGTH NOTED ON PLANS
12. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, and 1 hardcopy of other
documents. Pdfs must be uploaded using the form at:
https:Hedocs.deq.nc.gov/Forms/SW—Project—Submittal
ENCLOSED