SW1230602_Response To Comments_20230705

Legacy State Stormwater- Admin Review
Response to Comments
Good Morning,
We received your application for a new post-construction stormwater permit on 3/20/2023. At this time, the
submission is not administratively complete and cannot be accepted for review in its current condition. Please
provide the following submittal items within 30 calendar days (by close of business on 06/01/2023) so that we may
accept the project and begin the review process, otherwise, the project will be returned as administratively
incomplete.
Please provide 2x hard copies of revised sheets of the Application with the following:
1) Section IV, 9 - For high density projects, count 1 drainage area for each engineered stormwater SCM. Revise
the number provided in 9 to correspond to the number of SCMs provided. It appears that 1 SCM (the wet
pond) is being utilized, the vegetated swale bypassing the offsite drainage area does not need to be
included in this section.
Updated to reflect just 1 SCM.
2) Section IV, 10: Drainage Area - Please only include the drainage areas that are being treated by the SCM in
this section. When providing this number, please note that the drainage area shown in the plans on sheet C-
9.5: Post Development Drainage Map, will need to be revised to include all of the wet pond. (Note that the
Supplement-EZ "Entire Site" column is where the drainage area of the entire site will be accounted.)
Section IV, 10 has been updated to reflect only the drainage areas treated by the SCM(s).The previous
version of the drainage area map (C-9.5)was provided as assisting documentation to the Stormwater
Management Report(hydraulic analysis). The new drainage area map (C-9.7) has been added to show
drainage to each SCM (including all of the wet pond) in order to be consistent with the data on the
application.The Supplement-EZ has also been updated.
Please provide 2x signed & sealed hard copies of a plan sheet showing the following:
3) GENERAL MDCs 8 & 9 (15A NCAC 02H .1050(8) & (9)) - Please show the stormwater maintenance easement
on the plans and ensure the criteria are met. Stormwater maintenance access and easements for every SCM
must extend to the nearest public right-of-way.
SCM maintenance easement has been added on sheet C-9.8. Permanent recorded easement is in
progress by RHI Legacy Foundation (landowner and responsible party for O&M) and will be sent to
NCDEQ reviewer upon plan approval.
4) G.S. 143-214.7(b2)- Synthetic turf is noted on the plans. Please note that synthetic turf may be considered
either pervious or impervious depending on the specifications. Currently, the application, calculations,
Supplement-EZ, and plans reflect the intent for these to be pervious. The synthetic turf must meet the
specifications in 15A NCAC 02H .1055 MDC FOR PERMEABLE PAVEMENT. Please provide documentation in
the plans and calculations exhibiting adherence to these specifications. Otherwise, revise the package with
the synthetic turf accounted for as BUA.
Fields with synthetic turf are identified on sheet Athletic Field Surfacing Details(L-6.0) in addition to
the turf detail.The turf used meets the specifications in 15A NCAC 02H .1055 for permeable
pavement by exceeding the requirements.The requirement is 50in/hr, while the specified turf
provides 127in/hr.The underlaying material, 5' No. 57 stone, also meets these requirements. See
sheet L-6.0 for details and calculations. In addition, the specification sheet with infiltration calculations
from the manufacturer is attached.
5) 15A NCAC 02H .1053 (1 1)- Please provide a planting plan meeting the criteria in the MDC.

A planting plan has been provided as sheet L-1.7 which meets all criteria in 15A NCAC 02H .1053 (11).
Please refer to the MDC FOR WET PONDS (15A NCAC 02H .1053).
(1) Please provide calculations of the main pool surface area and volume sized using either the Hydraulic
Retention Time Method or SA/DA and Average Depth Method.
See attached calculations sheet.
(3) Please show sediment storage on plans. The forebay and main pool shall have a minimum sediment
storage depth of six inches.
Now shown on sheet C-9.2.
(5) Please provide calculations exhibiting the following:
(a) Forebay volume shall be 15 to 20 percent of the volume in the main pool.
(c)The water flowing over or through the structure that separates the forebay from the main pool shall
flow at a nonerosive velocity.
See both (a) and (c) in the attached calculations sheet.
(5) Please provide calculations exhibiting the following:
DRAWDOWN TIME. The design volume shall draw down to the permanent pool level between two
and five days.
See attached calculations sheet.
Provide a note for wet pond maintenance stating, "If sediment accumulates in the forebay in a manner that reduces
its depth to less than 75 percent of its design depth,then the forebay shall be cleaned out and returned to its design
state," per MDC FOR WETPONDS 5 (d).
Note shown on sheet C-9.2.