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HomeMy WebLinkAboutWPO202100004 Correspondence 2021-07-22608 Preston Avenue P 434.295.5624 Suite 200 IF434.295.1800 T I M M O N S GROUP Charlottesville, VA 22903 www.timmons.com July 22, 2021 Matt Wentland County of Albemarle Community Development 401 McIntire Rd, North Wing Charlottesville, VA 22902 RE: Southwood Phase 1 Blocks 9, 10, & 11 — VSMP Permit Plan Review — WPO-2021-00004 - Comment Response Letter Dear Mr. Wentland: We have reviewed your comments from March 11, 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. Provide a completed and signed DEQ registration statement. This will be a modification if the existing permit will be used. The signed registration statement will be provided once obtained. It is our understanding the technical review of the plan can be completed to reach an approval with this being a requirement of permit issuance. 2. Provide a signed certification. The signed certification will be provided once contractor has been selected. It is our understanding the technical review of the plan can be completed to reach an approval with this being a requirement of permit issuance. B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code Section 17-404. 1. The PPP appears to be acceptable at this time. Acknowledged. An updated PPP is included with this submittal. 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, 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. The underground storage facility A will need to be removed from beneath the parking and travelway in front of Lots 71 and 72 and relocated outside of any travelways or where its repair/replacement will affect a travelway/entrance to a building. Engineering recommends it be moved to behind lots like SWM B. The storage facility has been relocated and redesigned accordingly. The new location is located outside of the travelway and would not impede access to the buildings in the event of major maintenance. Further the system is outside of the ACSA easement as well so as not to impede their maintenance. This location is the best available location to provide for vehicular access for typical maintenance without impact or limitation to the site should major maintenance ever be required. 2. Provide a chart showing the overall nutrient credit requirements for the development (currently this plan and WP0201900062). Include the amounts for what has been treated on -site and what has been purchased. After the post -construction phosphorus control requirement reaches 10 lbs. /yr., VAC25-870-69(B)3 will need to be met. An overall phosphorous removal tabulation has been provided on Sheet C6.2 for this development, WP0201900062, and subsequently submitted Southwood PHA Blocks 11 and 12 (WP0202100022). This table will be provided with future WPO submissions associated with the approved rezoning. Please consider this a living document and guidance to demonstrate our intent and ability to provide the minimum 75%treatment credit on site. 3. This plan cannot be approved until the 3.95 lbs./yr. of nutrient credits have been purchased. Verify this meets 9VAC25-870-69 Section B and contact Ana Kilmer prior to purchasing credits. Acknowledged. This will be coordinated with Ana Kilmer and proof of nutrient credit purchase will be provided once the purchase has occurred. 4. The outlet from SWM B will need to be released into an adequate channel. Currently it appears to release on the slope above the existing road ditch. The outlet location has been adjusted to better align with the existing channel. Updated field collected topographic data has been added to better depict the existing drainage swale to the ex 30" culvert. 5. Label the steepness of the slopes and include a note that the maximum steepness is 2:1. This includes the slope around steps. Slope labels, as well as the requested note, have been provided on Sheets C5.3 — C5.5. No slopes exceed 2:1. 6. Provide a level area adjacent to parking (such as on Alley 1) so residents are not exiting their vehicle directly onto a slope. A 5' wide level area has been provided adjacent to New Leaf Drive. 7. Provide more detail on SWM A and SWM B, including on the outlet structures (particularly for SWM A, as the flow is split). Underground detention details have been provided on Sheets C6.6-6.8. 8. Provide details for the Contech Jellyfish system. Details have been provided on Sheets C6.9 and the jellyfish has been revised to a Hydro International upflow filter. 9. The landscaping plan is not being reviewed or approved with these plans, only the locations relative to the storm system. The proposed trees should not be located directly next to inlets (such as on Road 1). Acknowledged. Tree locations have been adjusted to provide more space between inlets and trees. Tree locations over top of SWM B have been coordinated with the manufacturer and deemed acceptable. Adequate soil depth for the selected species is provided see note on sheet 1-1.2 at the top of the sheet. D. Erosion and Sediment Control Plan (ESOP) 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. Show the trap needed for the wash rack on the Construction Entrance. Wash racks have been shown on all Construction Entrances. See Sheets C3.2 — C3.4. All runoff from vehicle washing at the Entrances is directed to downstream traps and basins via diversion dikes. An additional area for a small trap has been illustrated adjacent to the construction entrances. 2. Include a detail for a Paved Construction Entrance. A Paved Construction Entrance detail has been provided on Sheet C3.1 and is shown in E&SC Phase II, Sheets C3.5-C3.7. 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 bryan.cichocki@timmons.com . Sincerely, Brya Cichocki, PE Project Manager