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Home My WebLink AboutWPO201900062 Correspondence 2020-06-05. •#��0 i 0® 608 Preston Avenue P 434.295.5624 T I M M O N S GROUP suite 200 F 434.295.1800 Charlottesville, VA 22903 www.timmons.com June 5, 2020 Matt Wentland Albemarle County Community Dev. 401 McIntire Rd, Rm. 227 Charlottesville, VA 22902 RE: Southwood Redevelopment — Village 1- VSMP Permit Plan Review — WP0201900062 — Rev. 1 Comment Response Letter Dear Mr. Wentland: We have reviewed all of your comments from Rev. 1 dated May 14, 2020 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 signed Registration Form. A signed Registration Form has been included in the SWPPP. (Rev. 1) Comment addressed. 2. Provide a signed Certification. A signed Certification has been included in the SWPPP. (Rev. 1) Comment addressed. 3. Include the information on impaired waters in Section 7. The TMDL Report for Moores Creek has been included in the SWPPP. (Rev. 1) Comment addressed. Revision 1 comments: 4. The proposed area of disturbance is listed differently throughout the SWPPP and plans (12.88 ac. On the Registration Statement, 15.58 ac. In the Nature of Activity, 15.04 ac. In the VRRM not including forest and open space). Please revise to have the same acreage. The proposed area of disturbance has been revised on the plans and throughout the SWPPP. B. Pollution Prevention Plan (PPP) ENGINEERING I DESIGN I TECHNOLOGY The PPP content requirements can be found in County Code Section 17-404. 1. The PPP is acceptable at this time. Acknowledged. 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 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. A FDP permit application and a Flood Study will need to be submitted and approved [18.30.3.12, 18.30.3.13]. Acknowledged. A flood plain permit will be submitted/approved prior to the VSMP and final plat approval. Rev. 1 Comment not addressed. A draft of a Flood Study has been attached. However, this outfall has been recently revised. A final Flood Study for the proposed outfall shall be submitted prior to plan approval. 2. This plan cannot be approved until the 1.84 Ib/yr of nutrient credits have been purchased. Please contact Ana Kilmer prior to purchasing credits. Acknowledged. We have reached out to Ana Kilmer in regard to purchasing nutrient credits. Note that with the revised routing, 1.38 Ib/yr of nutrient credits is required. Rev. 1 Comment not addressed. We have reached out to Ana Kilmer in regard to purchasing nutrient credits. 3. Please contact Ana Kilmer to complete a Stormwater Management Facilities Maintenance agreement. We have reached out to Ana Kilmer to complete a Stormwater Management Facilities Maintenance agreement. Rev. 1 Comment addressed, the agreement will need to be recorded prior to approval. We have reached out to Ana Kilmer to complete a Stormwater Management Facilities Maintenance Agreement. 4. The Forest and Open Space Easement, SWM Facility easements and Mitigation easement will need to be shown on the Final Plat and a Deed of Dedication will need to be signed and recorded for this easement. The Deed will be filled out by the County and forwarded to the applicant when the plat is nearing approval. Acknowledged. Rev. 1 Response noted. 5. Show and label all proposed easements on the plans, including facility and access easements. All easements have been shown and labeled on the Grading and Drainage Plan on sheets C4.05-C4.08. Rev. 1 Comment partially addressed. Revise the easement linetype so it shows up clearer. Show easements on the entrance culvert, structure 600 on the entrance road, and on the structures/pipes in the parking lots of the proposed apartment buildings (others may not be listed). Easements have been added at structure 600 and through parking lots at condo buildings. 6. Clearly shown and label how the bioretention will be accessed for maintenance. An access easement has been added in the vicinity of pipe 201. Rev. 1 Comment partially addressed. The maximum slope for a grassed access is 20%, please revise. [Design Standards Manual]. Grading has been revised to 20% maximum for 10' wide access path. 7. Include the bioretention maintenance and inspection schedules from DEQ BMP Spec. 9 on the plans. DEQ BMP Spec. 9 maintenance and inspection schedules have been added to the Stormwater Summary on sheet C6.01. Rev. 1 Comment addressed. 8. Include the planting plans for the bioretention. A planting plan has been added for the bioretention. See sheet L1.01 and L1.02. Rev. 1 Comment partially addressed. Only one biofilter shows any plantings on the landscape plan. Provide separate details/tables for the biofilter plantings following the requirements in DEQ BMP Spec. 9 sections 6.8 and 6.9. Plantings for both biofilters have been shown on sheets L1.01 and L1.02. 9. Provide the routing calculations for the bioretention. Bioretention routing calculations have been included in the calculation book. Rev. 1 Comment addressed. 10. Show and label the pre-treatment requirements for the level 2 bioretention on the plans. Gabion basket forebay wall details have been added to sheet C6.00. Rev. 1 Comment partially addressed. Show and label both of the two required pre - treatments for each Level 2 biofilter. Include the size of the pre-treatment cells. [DEQ BMP Spec. 9, Table 9.3 and Section 6.4] Per Table 9.4, pre-treatment cell and gravel diaphragm have been provided at each bioretention basin. Riprap-lined pre-treatment cell has been added to detail for additional clarity. 11. Provide more detail on the path through bioretention 2. Bioretention 2 has been relocated and revised. (Rev. 1) Comment addressed. 12. Include the County As -built requirements on the plans. The As -built Road Plan policy has been added to the Notes and Details on Sheet C1.00. Rev. 1 Comment not addressed. Include the VSMP As -built requirements. The VSMP As -Built requirements have been added to sheet C1.00. 13. On Sheet C6.0, include a breakdown of the proposed and conceptual impervious areas in each biofilter drainage area. The proposed and conceptual impervious areas have been labeled for each drainage area on sheet C6.00. Rev. 1 Comment addressed. 14. Show more detail for the outfall into the stream. Include the stream banks, as it will need to outfall directly in the stream to not use energy balance. Include a drainage area map for the stream to show the 1% is being met. Outfall location has been revised. 1% drainage area map has been added to plans on sheet C6.02. Rev. 1 The provided DA map appears to be incorrect. Areas are included that enter the stream below the proposed outfall and areas that drain to the other side of the Interstate. I've attached a printout from County GIS showing the drainage area at the pipe outfall. Stormwater management approach has been revised to include an oversized storage pipe to meet energy balance requirements. See sheet C6.00 for additional information. 15. Contact the Army Corp and provide correspondence allowing the outfall into the stream. We have reached out to the Army Corp pertaining to the outfall into the stream. Rev. 1 Comment not addressed, response noted. We are in communication with the Army Corp on the revised outfall and will provide correspondence in future submittals. 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 approved, 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. The ESC ",mien appeaFs acceptable at this time Acknowledged. Revision 1 Comments: 2. Provide a sediment trap for the grading on the northeast side of the entrance. The final grading should also be revised to direct the runoff to the culvert instead of having channelized runoff flowing into the road. Sediment Trap #3 has been added. Ditch has been added in the proposed condition to direct runoff to culvert. Note that storm pipes along Road 1 have been sized for future development by others on this parcel with approximately 80% impervious surface. We have included PDF copies of the plans and calculations for your review. If you have any questions or comments, please feel free to email me at clint.shifflett@timmons.com . Sincerely, Clint Shifflett, PE Project Manager