SW4220503_Response To Comments_20220909

2524 Reliance Avenue
Apex, North Carolina 27539
FOR:
DATE:
RE:
Jim,
.:
BCSC
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Ei,hFEMAN CIVIL SURVEY COMPANY
Division of Water Resources — NC Department of Environmental Quality
Attn: Jim Farkas
512 N. Salisbury Street, Office 640M
Raleigh, NC 27604
September 9, 2022
Cane Creek Phase 8 — Stormwater Submittal
SW4220503
Please see the following comment responses:
Review Comments 08.25.22 — Stormwater Engineer
Please correct the following:
Phone: [phone]
[e-mail]
General:
1 Please upload the electronic files associated with this project as instructed per the 6/8/2022 email below at the
link provided (https:Hedocs.deg.nc.gov/Forms/SW-Supplemental-Upload).
Response: Electronic files have been uploaded as requested.
2 This project drains to a Nutrient Sensitive Water (NSW). Please provided documentation showing that 15A
NCAC 02H .1017(9)(c) is being met.
Response: Documentation has been provided that 15A NCAC 02H .1017(9)(c) is being met. SCM
Treatment swales have been designed to meet requirements, required document are provided for review.
Riprap lined swales are not vegetated conveyances. Per 15A NCAC 02H .1003(2)(c), non -vegetated
conveyances are only allowable for low -density projects when they cannot be avoided (these riprap lined swales
appear to be able to be avoided by reconfiguring the on -site drainage and by reducing the area draining to these
swales). For example, the flow along the east side of Harrier Lane is broken up between swales 7 & 8 via a
cross -culvert, something similar to this and/or relocating and/or adding some swales could reduce the need for
riprap lining on these certain swales.
Response: Ditches have been revised. There are no more swales lined with riprap. All swale are lined
with a vegetated conveyance and calculations have been provided in the permanent ditch calculations.
4 Please ensure that the on -site surface water area is accounted for in Section IV, 6 of the Application and on Line
4 of the Cover Page of the Supplement-EZ Form. The surface water area is the area between the banks of any
blue line streams shown on the USGS topographic map. You may need to recalculate the project density and
update it in the Application and Supplement-EZ Form.
Response: Applications have been revised to account for on -site surface water.
Calculations:
1. Please provide a source for the 10-year storm intensity values used in the swale calculations. If you are using a
time of concentration in excess of 5 minutes, please also provide the time of concentration calculations.
Response: 10-year storm table from NOAA has been provided in the permanent diversion ditch
calculations. Time of concentration used is 5 minutes.
2. The actual swale velocities shown in the calculations and Supplement-EZ Form do not appear to be correct. For
example, using Manning's Equation for Swale 1 and the provided variables from the actual conditions (n = 0.025,
A = 7.0 sf, Wp = 8.32 ft, R = 0.84, & S = 0.059 ft/ft) results in a flow value of approximately 90 cfs (The provided

Bateman Civil Survey Company, PC
Page 2
calculations show that the 10-year design flow is approximately 10 cfs so the velocity derived from the 90 cfs
flowrate is not reflective of the 10-year design storm). Please ensure that the calculations show the velocity for
the 10-year design storm as required per 15A NCAC 02H .1003(c)(ii).
Response: Ditch velocity rates have been revised using 10yr intensity of 5.09inlhr. Revised velocities
have been provided for your review.
3. Please provide a source/detail for the mattings/swale liners showing the maximum allowable velocities. Please
note that these liners must be permanent if they are to be used to show that the velocity is non -erosive.
Alternatively, you may use the maximum allowable velocities shown in Part C-11 of the Manual.
Response: Detail for the swale liners has been provided in the permanent diversion ditch calculations.
Application:
1. Section IV, 6 — Please include the on -site surface water area.
Response: On -site surface water area has been included.
2. Section IV, 7 & 10 — Please ensure that the on -site surface water area is excluded from the Project/Drainage
Areas. Please recalculate the % BUA as needed.
Response: On -site surface water area has been excluded from the Project/Drainage Areas and the %
BUA has been recalculated.
Section IV, 8 — Please recalculate the % BUA as needed.
Response: % BUA has been recalculated.
Supplement-EZ Form:
1. Cover Page:
Line 2 — Please ensure that the on -site surface water area is excluded from the Project Area.
Response: On -site surface water has been excluded from the Project Area.
Line 4 — Please include the on -site surface water area.
Response: On -site surface water area has been included.
2. Drainage Area Page:
Entire Site Column — Please complete the entire site column. For this project, the entire site column will match
the LID 1 column.
Response: Entire site column has been filled out.
Lines 5 & 6 — Please ensure that the on -site surface water area is excluded from the Project/Drainage Areas.
Response: On -site surface water area is excluded from the Project/Drainage Areas.
Line 12, Roof — The BUA allocated to the individual lots should not be recorded on this line (Line 12 is the
breakdown of all BUA not located on subdivided lots).
Response: BUA has been removed from this line.
Line 18 — Please recalculate the % BUA as needed.
Response: % BUA has been recalculated.
Line 19 — This item is not required for low -density projects.
Response: Noted.
3. Low -Density Page:
Line 5 — Please provide this value. If there are formatting issues with this cell, please place this information in the
additional information section (Line 15).
Response: Value has been provided.

Bateman Civil Survey Company, PC
Page 3
Line 12 — This item is required per 15A NCAC 02H .1003(4)(e).
Response: Item has been revised and dissipator pad has been provided.
Line 13 — This item is required per 15A NCAC 02H .1003(5).
Response: Revised, dissipator pas has been provided.
Line 14 — Please answer this item.
Response: Revised, there are no variations to rule .1003.
Please provide the following:
- 1x electronic copy of the submittal items originally requested on 6/8/2022.
- 1x hard copy & 1x electronic copy of the revised pages of the calculations.
- 1x hard copy & 1x electronic copy of the revised pages of the Application.
- 1x hard copy & 1x electronic copy of the revised pages of the Supplement-EZ Form.
- 1x hard copy (2x hard copies for plan sheets) & 1x electronic copy of anything else needed to address these
comments.
Hard copies should be mailed to me at the following address:
For FedEx/UPS:
Jim Farkas
512 N. Salisbury Street, Office 640M
Raleigh, NC 27604
Hand Delivery:
Please reach out to me prior to hand delivering a submission to make sure that I (or someone else in my group) will
be able to receive the submission. Do not leave the package in the foyer with the security guard.
NOTE: Hard copies should not be sent to a Regional Office. Doing so will delay the review process and the
submission package may be lost while being sent from the Regional Office to me in the Central Office.
Electronic copies should be uploaded at the following location:
https:Hedocs.deg.nc.gov/Forms/SW-SuPPIemental-Upload
Please provide these items within 30 calendar days or the application will be returned as incomplete. The return of a
project will necessitate resubmittal of all required items, including the application fee. Please reference the State
assigned project number SW4220503 on all correspondence.
If you need additional time to submit the information, please submit your request for a time extension to the Division
at the contact below. The request must indicate the date by which you expect to submit the required information. The
Division is allowed 90 days from the receipt of a completed application to issue the permit.
The construction of any impervious surfaces, other than a construction entrance under an approved Sedimentation
Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject to enforcement action pursuant to NCGS 143-
215.6A.
If you have any questions concerning this matter, please feel free to contact me at Jim. Farkas(o)ncdenr.gov or (919)
707-3646.
Kind Regards,
Thomas S. Speight Jr., PE
Civil Engineering & Land Development
P: 919.577.1080
tom(o)batemancivilsurvey.com