SW3220301_Response To Comments_20220420

Kevin E. Herring ENGINEERING
16101 Silver Road, Oakboro NC 28129, 980-621-0935, [e-mail]
February 12, 2022
Memo To: Jim Farkas
NCDEQ Stormwater
From: Kevin E. Herring PE
Reference: Re -Submittal of Mini Warehouse USA
3622 W. Hwy 74, Wingate NC
This shall serve as a response to comments provided via email dated 1/18/22.
Please note that this re -submittal also reflects plan revisions for DEQ-EC and NCDOT. For your reference I have
included a breakdown of revisions previously provided to DEQ-EC. DEQ-EC revisions impacted the size and location of
skimmer basin which impacted the final SCM. NCDOT revisions primarily reflect the ADA ramps and showing milling
at the proposed entrance. Erosion Control has been approved.
Due to these revisions, full sets of plans and calcs have been provided in lieu of individual sheets.
For current DEQ-SW revisions:
1. SWU-101 application provided
2. Missing O&M Agreement pages provided
3. Supplement-EZ Form has been updated and provided. Note I may have not filled "Entire Site" column
correctly. All impervious area on the site drains to the proposed SCM.
4. DA sheet has been added to the plan set
5. No jurisdictional features on site and verification has been provided and noted on SWMP plan.
6. All offsite areas bypass the SCM except a small area in the existing NCDOT street and R/W. This area is fully
developed including our addition of the portion of the proposed entrance and sidewalk in the R/W. Roofs of the
proposed buildings will be designed to slope inward into the property to drain to SCM. All exterior areas
bypass the SCM except the portion in the existing street R/W as noted above.
Please advise if additional information is needed.
kh

BREAKDOWN OF REVISIONS
NOTE: REVISONS DID NOT INCREASE DISTURBED AREA
POND OUTFALL CULVERT
Pond outfall culvert is specified as ADS N-12 Type S which is a double wall pipe with is sufficient
for the compacted pond dam. Per their spec. Class 3 material compacted to 95% allows for a
maximum cover of 18 feet. The pond only has a maximum height of 6 feet. The typical 20' pipe
lengths allow for less joints. With this revision, I have further clarified in the pond detail notes
that the pipe shall be "double wall type S" and that "all associated joints have watertight seals"
SKIMMER REVISIONS INCLUDE:
1. Surface area revised to 435 x Q10
2. Top of Dam widened to 10 feet in extents of future permanent SCM pond
3. Interior slope is 3:1. Exterior slope is 2.5:1
4. Pond location adjusted slightly to accommodate 10' dam width and exterior slope
5. Emergency Spillway moved to cut section. Size also adjusted.
6. Confirmed 2' depth btw invert and top of riser (weir)
7. Adjusted elevations such that there is 1.0 ft freeboard btw top of riser (weir) and emer.
spillway
TD Revisions
l . TD detail on Sheet 8 revised as request to reflect 2' crest width
2. Portion of TD along top of slope removed
3. Fill slope revised to be incorporated as a dam for an extended area of the SB allowing for
it to be constructed during the initial grading phase.
4. Toe of slope moved 10' off channel for buffer. This area noted as 20' SDE
5. Top of dam in this area noted as minimum of 8' width. Exterior slope 2:1
6. Soil stockpile area relocated
7. Area noted to be filled and compacted upon full stabilization and established ground cover
of upstream basin
8. Confirmed that skimmer crest elevation of riser weir for final pond design exceeds required
SA of skimmer basin (435 x Q10) allowing for fill of extended area.
Other Changes
1 Building #2 and # 4 lengths shortened to revised pond location.
2. Building #1 lengthened to offset change in storage of Bldg #2
3. Building #7 size adjusted due to grading changes
4. Building #8 added to compensate
5. Minor changes to parking area
SUMMARY OF SHEET REVISONS
1. Cover sheet revised to reflect revision date
2. Site Plan (slit 2) revised to reflect building changes
3. SWMP (slit 4) revised to reflect associated pond changes
4. SWMP Details (slit 5) revised to reflect associated pond changes
5. EC plan (slit 6) revised to reflect grading changes
6. EC Details (sht 8) revised to reflect SB detail changes