HomeMy WebLinkAboutWPO202100054 Correspondence 2021-10-15608 Preston Avenue
P 434.295.5624
Suite 200 F 434.295.1800
T I M M O N S GROUP
Charlottesville, VA 22903 www.timmons.com
October 15, 2021
John Anderson
County of Albemarle
Community Development
401 McIntire Rd, North Wing
Charlottesville, VA 22902
RE: Keswick Family Pool — VSMP Permit Plan Review — WP02021-00054 - Comment Response
Letter
Dear Mr. Anderson:
We have reviewed all of your comments from October 7, 2021 and made the necessary
revisions. Please find our responses to the comments below in bold lettering.
A. 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. Revise the SWPPP title page to include ref. to W130202100054.
The WPO number has been added to the title page.
2. Please check to see if file 'flatten' issue may have affected SWPPP submittal by
stripping information; thanks for discussing this with me 10/06/2021.
Acknowledged. The SWPPP has been 'flattened'.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code Section 17-404.
Acknowledged.
ENGINEERING I DESIGN I TECHNOLOGY
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is disapproved for reasons listed below. The stormwater management plan
content requirements can be found in County Code Section 17-403.
1. General:
a. Add WP0202100054 to calculation packet cover.
WPO202100054 has been added to the cover sheet of the calculation
packet.
b. Add WP0202100054 to plan title sheet.
WPO202100054 has been added to the plan title sheet.
2. C4.0:
a. Show/label public drainage easement (SWM facility outfall pipe).
Drainage and SWM facility easements have been added to the plan. Please
see sheet C6.6 for a clear depiction of the easements to be recorded with
the plat.
b. Show/label SWM facility easement.
Drainage and SWM facility easements have been added to the plan. Please
see sheet C6.6 for a clear depiction of the easements to be recorded.
c. Please find easement application at:
https://www.albemarle.org/home/showpublisheddocuments/1052/6376240
89314100000
Acknowledged.
3. C5.0:
a. Note 3: Please ensure comment allowing contractor discretion with rooftop
storm routing is consistent with post -developed hydraulic routings in
calculation packet. Allowing the contractor flexibility to route roof leader
lines to 'nearest inlet' is inconsistent and may cause discharge higher than
reported in the calculation packet, if runoff intended to reach detention
bypasses detention.
Note 3 on sheet C5.0 has been revised to be consistent with the intent of
the SWM calculation packet.
b. Recommend label, note, or legend identify permeable pavers as Level 1
permeable pavers.
A label has been added to this sheet to identify the permeable pavers as
Level 1. On sheet C4.0 the hatching legend has been revised to "Level 1
Permeable pavers."
4. C6.2:
a. Include Construction Installation steps from VA DEQ Stormwater Design
Specification Design Specification No. 7.
The Construction Installation steps have been added to sheet C6.2.
b. Include underground detention Mfr. Specifications, typical details, and
specific details for proposed SWIM facility.
Please see details on Sheet C1.3.
5. C6.3:
a. Check upgradient drainage areas for Area 2 and Area 3, since it appears
upgradient areas may drain to permeable pavers in these areas.
Consistent with Approved WPO Plan WPO-2018-00078, upstream pervious
areas are intercepted with a gravel filter strip and underdrain prior to
draining onto the permeable pavement. The underdrain system conveys
runoff to the applicable storm structures.
b. Check CDA ratio, 3.09:1, permeable pavement drainage area 4, since VA DEQ
Stormwater Design Spec. Level 1 max. CDA ratio is 2.5:1. Revise, as needed.
A storm inlet has been added upgradient of the permeable pavement
section. The drainage area has been revised and the calculations has been
updated.
6. C6.0:
a. Stormwater Narrative: Please revise/clarify lb. nutrient credits proposed
(0.33 or 0.26 lb.)
The error has been corrected. With plan updates the correct amount is 0.34
pounds. The plans and stormwater narrative have been updated
accordingly.
D. 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 for reasons listed, below. The erosion control plan content
requirements can be found in County Code Section 17-402.
1. C3.0:
a. Check sediment trap #2 wet storage provided (61.9 cy) v. storage required
(65.5 cy).
The calculations have been revised.
2. C3.2:
a. Compare area of disturbance, 1.75 Ac., with VRRM.xIs 1.53 Ac. Please
reconcile.
The limits of disturbance has been reconciled.
b. Label ST1 floor dimensions, L x W.
Dimensions have been added to STl.
We have included PDF copies of the plans and calculations for your review. If you have any
questions or comments, please feel free to give me a call at 434.295.5624 or email at
Jessica.denko@timmons.com .
Sincerely,
Jessica Denko
Project Manager