HomeMy WebLinkAboutWPO202000028 Correspondence 2020-10-22SHIMP ENGINEERING, P.C.
Design Focused Engineering
October 22, 2020
David James
County of Albemarle
Department of Community Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Response Letter #2 for WP0202000028 — Regent School of Charlottesville
Dear David,
Thank you for your review of the VSMP request for Regent School of Charlottesville. This letter contains
responses to County comments dated September 14, 2020.Our responses are as follows:
B. Stormwater Pollution Prevention Plan (SWPPP)
The SWPPP content requirements can be found in County Code section 17-405. A SWPPP
must contain (1) a PPP, (2) an ESCP, (3) a SWMP, and (4) any TMDL measures necessary.
1. You'll need to update Section 5. See comment D.1. (Rev.1) Not currently addressed.
Acknowledged, Section 5 hasn't been updated, as the channel is manmade per
Frank Pohl's email. Therefore, our SWM actually correct.
2. Complete Section 9 prior to approval. (Rev.1) Not addressed.
Acknowledged, Section 9 in the SWPPP file has been completed with this
submission.
C. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1. Show staging, stockpile, borrow, concrete washout locations on the PPP. Also, show
locations where concentrated stormwater may discharge. (Rev.1) Partially addressed.
Please show entire area (LOD) of site.
Acknowledged, PPP has been updated so that it is showing the full LOD.
2. Show possible stockpile/waste areas with silt fence around it. (Rev.]) Partially
addressed. Show on PPP.
Acknowledged, PPP has been updated so that it is multiple phases to match the
phases of the E&S Plan Phases.
D. Stormwater Manaeement Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is disapproved, and the reasons are provided in the comments below. The
stormwater management plan content requirements can be found in County Code section 17-
403.
1. You're discharging into a natural channel/stream and therefore site runoff must satisfy
Energy Balance regardless if the 2 LOA criteria are met in 9VAC25-870-66.B.4. (Rev.1)
SHIMP ENGINEERING, P.C.
Design Focused Engineering
Not addressed. This channel naturally floods (uncontained) and it's floodway is
mapped out by FEMA. As discussed, and through emails by local DEQ office it has
been determined that the POA is at a natural channel and Energy Balance must be
meet there.
Acknowledged, per email from Frank Pohl, this is a manmade channel.
2. Show Forest/Open Space protected in an easement. Submit an easement plat. Plat & deed
will need to be recorded prior to VSMP plan approval. (Rev.1) Partially addressed.
SWM easement plat & deed will need to be reviewed & recorded.
Acknowledged, the plat will be submitted in several days.
3. Provide HGL in profiles (LD-347). (Rev.1) Partially addressed. Provide the calcs
worksheet as well.
Acknowledged, LD-347 are provided with SWM packet included in this submission.
E. Erosion and Sediment Control Plan (ESCP)
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an
ESCP. This plan is disapproved, and the reasons are provided in the comments below. The
erosion control plan content requirements can be found in County Code section 17-402.
1. Sediment Traps: The height, H (ft.) are reported incorrect in the table on sheet 14 and
need to match the height shown on the plans. See the width to height table below. (Rev.1)
Revise ST-1 & 2 to meet spec minimums. I measure ST-1 to have H=6' and W=3.5',
ST-2 to have H=6'
1"2
3.13
MINIMUM TOP WIDTH (W)
REQUIRED FOR SEDIMENT
TRAP EMBANKMENTS
ACCORDING TO HEIGHT OF
EMBANKMENT (FEET)
Source: Va. DSWC
I-- w -a
x �
.5 0.5 2.0
2.0 1.0 2.0
2.5 1.5 2.5
3.0 20 2.5
J.5 2:5 3.D
,.0 3.D 3.D
5 3.5 a.D
5.0 4.0 4.5
rmwwnn
r
err..
xa ovm =
ommw
cxwxo
euv.
Plate 3.13-1
and w=3.5' embankment.
Acknowledged, ST-1 & ST-2 H=5'. The W have been revised to match the table you
provided. With this revision, W=4.5'. Please note that ST-2 have been shifted
upwards to meet the requirements.
SHIMP ENGINEERING, P.C.
Design Focused Engineering
F. Mitigation Plan IMP)
The mitigation plan requirements can be found in County Code Chapter 17-406.
1. (Rev.1) Provide total SF of canopy coverage. Ensure 2:1 area coverage.
Acknowledged, Total Canopy is now provided. Please see sheet C11.
If you have any questions or concerns about these revisions, please feel free to contact me at
Stephaniekshimp-en ing eering com or by phone at 434-227-5140.
Regards,
Stephanie Paul
Shimp Engineering, P.C.