SW5200501_Email_20200918

Georgoulias, Bethany
From: Farkas, Jim J
Sent: Friday, September 18, 2020 10:54 AM
To: Josh Crumpler
Subject: RE: [External] Re: SW5200501 - Coolwick Warehouse
Josh,
I was looking over the additional information you provided on 9/16/2020. Everything looks good except for a few small
issues:
Please correct the following:
- General:
o The sediment storage elevation needs to be accounted for. When calculating the volume of the main
pool or forebay, the volume of the sediment storage is excluded. For example, if the sediment storage
top elevation for the main pool is at elevation 392 ft, then the stage -storage table would start at this
elevation, not at the excavated bottom elevation (391.5 ft). It does not appear that accounting for the
sediment storage elevation will require a redesign of the pond.
o The forebay entrance must be deeper than the forebay exit. Figure 5 in the Wet Pond Chapter of the
Manual shows more or less what we are looking for (See attached sketch for how this can be
incorporated in your design).
o Typically, the vegetated shelf plant density of 50 plants per 200 sf equates to 2 foot on center spacing (3
foot on center is shown) please ensure that the planting density is adequate.
- Application:
o Section IV, 10 —The impervious surface area table needs to be updated to account for the existing BUA
as such:
Impervious" Surface Area
Drainage Area 1
Buildings
25400
Streets
16974
Parking
2705
Sidewalks
669
Existing BUA
12633
Tota 1
58381
- Calculations:
o Main Pool Volume:
■ As noted above, the main pool volume calculation (Stage -storage table) does not account for
the sediment storage area. Assuming that the sediment storage top elevation in the main pool is
at elevation 392 ft (6 inches above the excavated bottom), the stage -storage table for the main
pool would look like the following:
Stage
SA
Volume
392
2456
-
393
2723
2590
394
2997
2860
395
3280
3139
396
3570
3424
Total 4
j 12013

o The average depth calculation will need to be updated with the new main pool volume. (12,013 cf /
3,570 sf = 3.4 ft)
o Forebay Volume:
As noted above, the forebay volume calculation (Stage -storage table) does not account for the
sediment storage area. Assuming that the sediment storage top elevation in the forebay is at
elevation 393 ft (6 inches above the excavated bottom of the forebay exit and 12 inches above
the excavated bottom of the forebay entrance), the stage -storage table for the main pool would
look like the following:
Stage
SA
Volume
393
629
-
394
738
684
395
855
797
396
979
917
Total 4
2397
NOTE: This results
in a forebav volume that is witl
main pool).
iin 15-20% of the main pool volume. (19.9% of
o Please provide calculations showing that the inlets and outlets are stable per prior comment 3c.
- O&M-EZ Form:
o The O&M-EZ Form is filled out correctly, just make sure that the original, signed hard copy gets
submitted.
- Supplement-EZ Form:
o Cover Page:
■ Filled out correctly, just make sure that the original, signed hard copy gets submitted.
o Drainage Areas Page:
■ Drainage Area 1 Column, Line 18—This is the design volume based on the 1" design storm
(4,762 cf per the calculations).
o Wet Pond Page:
■ Line 2 - This is the design volume based on the 1" design storm (4,762 cf per the calculations).
■ Line 21—The top of the sediment storage zone must be included. This item must be at least 6
inches above the excavated bottom of the main pool (Line 20).
■ Line 25—The temporary pool elevation is based on the design volume. The O&M-EZ Form
appears to have the correct value for this (396.85 ft).
■ Line 27 —See prior comment.
■ Line 28—The average depth of the main pool is calculated (Using Eq. 2) as the volume of the
permanent pool (Line 27) divided by the surface area of the main pool (Line 26) (Equal to about
3.4 ft).
■ Line 32 — See prior comment.
■ Line 34—The cleanout depth of the forebay is the vertical distance from the permanent pool
elevation (396 ft) to the top of the sediment storage elevation (Line 21), expressed in inches.
■ Line 35 — NOTE: This value is correct. This item is the actual provided volume whereas Line 2 is
the design volume based on the design storm.
■ Line 37 —This value (2 in) does not match the plans (1.25 in). Revise as needed. NOTE: The cell
may not readily accept numbers with a decimal. If this is the case, you can put a note on Line 55
with the correct value.
■ Line 44 — See prior comment.
■ Line 48 —Typically, if a bent elbow is present on the drawdown orifice, the drawdown orifice
draws from below the permanent pool elevation.
■ Line 53 — Please specify the type of grass cover that will be used on the embankment of the wet
pond (It can't be a clumping grass).
■ Line 54—A planting plan has been provided (Sheet C-9).
- Plans

o Please show the sediment storage top elevations (Sheet C-9) for both the forebay and main pool.
o The riser detail (Sheet C-9) shows the drawdown orifice as 2 in. (1.25 in. in the profile) and the invert as
490.50 ft (396.00 ft in the profile).
o The emergency spillway detail (Sheet C-9) shows the spillway elevation at 493.25 ft (397.75 ft in the
profile).
o Please specify the type of grass cover that will be used on the embankment of the wet pond (Sheet C-9)
Please provide the following:
- Revised Plans — 2x hard copies of the revised sheets (revised from prior submittal) and 1x full electronic copy of
the plans uploaded to Laserfiche.
- Revised Application — 2x hard copies of the revised pages (revised from prior submittal) and 1x full electronic
copy of the Application uploaded to Laserfiche. New signature is not needed.
- Revised Calculations — 1x hard copy of the revised calculations and 1x full electronic copy of the calculations
uploaded to Laserfiche. Don't forget original signature.
- Revised Supplement-EZ Form — 2x hard copies of the revised pages (revised from prior submittal, don't forget
original signature) and 1x full electronic copy of the Application uploaded to Laserfiche.
Since these are really minor things, once I get the hard copies, anything else that may have changed from addressing
these issues, and the documents are uploaded to Laserfiche (Provided everything is still in order), we can issue the
permit without doing another formal 30-45 day review.
Let me know if you have any questions or would like to discuss.
Jim Farkas
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral, & Land Resources — Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
[phone]
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19, the Department of Environmental Quality has
adjusted operations to protect the health and safety of the staff and public. Many employees are working remotely or
are on staggered shifts. To accommodate these staffing changes, all DEQ office locations are limiting public access to
appointments only. Please check with the appropriate staff before visiting our offices, as we may be able to handle your
requests by phone or email. We appreciate your patience as we continue to serve the public during this challenging
time.

From: Josh Crumpler <[e-mail]>
Sent: Wednesday, September 16, 2020 1:44 PM
To: Farkas, Jim J <[e-mail]>
Cc: larry Coole <[e-mail]>
Subject: [External] Re: SW5200501 - Coolwick Warehouse
External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
[e-mail]
Jim,
I just sent an email with a link to download the resubmittal we discussed. If you can't download from the link I
can email the plans and report individually as the file sizes are large.
Josh
Josh Crumpler, PE
Crumpler Consulting Services, PLLC
919-413-1704
From: Josh Crumpler <[e-mail]>
Sent: Wednesday, September 2, 2020 11:48 AM
To: Farkas, Jim J <[e-mail]>
Subject: Re: SW5200501 - Coolwick Warehouse
Thanks Jim. I'll make sure to have all this over to you next week via email to make sure it is designed correctly.
Josh
Josh Crumpler, PE
Crumpler Consulting Services, PLLC
919-413-1704
From: Farkas, Jim J <[e-mail]>
Sent: Wednesday, September 2, 2020 11:39 AM
To: Josh Crumpler <[e-mail]>
Subject: RE: SW5200501 - Coolwick Warehouse
Josh,
4

The riprap sizing charts I mentioned are located on pages 151 and 152 of the linked PDF
(https://f i I es. nc.gov/ncdeg/Energy % 20M i ne ra I % 20a nd % 2OLa nd % 2OReso u rces/Land % 20Reso u rces/Land % 2OQua I ity/E ro
Sion%20and%20Sediment%20Control%20Planning%20and%20Design%20Manual/Chapter%208/Chapter%208 rev%20
May% 202013. pdf).
Per an earlier version of our rules, we used to require that clay liners be 6-12 inches thick and not have a permeability
greater than 0.01 in/hr. As stated in our phone conversation today, the rules no longer require the liner, but it is
recommended in locations with well -drained soils so that the permanent pool remains permanent.
Let me know if you have any questions,
Jim Farkas
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral, & Land Resources — Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
[phone]
Jim. Farkas kncdenr. gov
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19, the Department of Environmental Quality has
adjusted operations to protect the health and safety of the staff and public. Many employees are working remotely or
are on staggered shifts. To accommodate these staffing changes, all DEQ office locations are limiting public access to
appointments only. Please check with the appropriate staff before visiting our offices, as we may be able to handle your
requests by phone or email. We appreciate your patience as we continue to serve the public during this challenging
time.
From: Farkas, Jim J
Sent: Friday, August 28, 2020 3:42 PM
To: Josh Crumpler <[e-mail]>
Cc: Valentine, Thad <[e-mail]>
Subject: RE: SW5200501 - Coolwick Warehouse
Good Afternoon,
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater Management Permit Application
for the subject project on July 28t", 2020. A review of that information has determined that the application is not

complete. Attached is a letter describing the items that need to be submitted. If you have any questions, please feel free
to contact me. My contact information is listed below.
Thank you,
From: Farkas, Jim J
Sent: Friday, June 19, 2020 10:19 AM
To: Josh Crumpler <[e-mail]>
Cc: Valentine, Thad <[e-mail]>
Subject: SW5200501 - Coolwick Warehouse
Good Morning,
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater Management Permit Application
for the subject project on May 8t", 2020. A review of that information has determined that the application is not
complete. Attached is a letter describing the items that need to be submitted. If you have any questions, please feel free
to contact me. My contact information is listed below.
Thank you,
Jim Farkas
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral, & Land Resources — Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
[phone]
Jim. Farkas kncdenr. gov
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Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19, the Department of Environmental Quality has
adjusted operations to protect the health and safety of the staff and public. Many employees are working remotely or
are on staggered shifts. To accommodate these staffing changes, all DEQ office locations are limiting public access to
appointments only. Please check with the appropriate staff before visiting our offices, as we may be able to handle your
requests by phone or email. We appreciate your patience as we continue to serve the public during this challenging
time.