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HomeMy WebLinkAboutWPO201900043 Correspondence 2020-02-05s �t TIMMONS GROUP YOUR VISION ACHIEVED THROUGH OURS. February 3, 2020 Emily Cox County of Albemarle Dept. of Community Dev. 401 McIntire Rd. Charlottesville, VA 22902 608 Preston Avenue P 434.295.5624 Suite 200 F 434.295.8317 Charlottesville, VA 22903 www.timmons.com RE: AutoZone Charlottesville Store #6464 — VSMP Permit Plan Review — WP0201900043 - Comment Response Letter Dear Ms. Cox: We have reviewed all of your comments from December 16, 2019 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. Registration statement must be filled out and signed. Acknowledged. The signed registration statement will be provided prior to final site plan approval. Rev.1: Comment not addressed. The registration statement will be signed once property has been purchased by the developer. 2. Section 9 (signed certification) must be signed. Acknowledged. Executed signed certitication page will be provided prior to final site plan approval. Rev.1: Comment not addressed. The signed certification will be signed once property has been purchased by the developer. B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code section 17-404. 1. No comments. 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 CIVIL ENGINEERING I ENVIRONMENTAL I SURVEYING I GIs I LANDSCAPE ARCHITECTURE I CONSTRUCTION SERVICES stormwater management plan content requirements can be found in County Code section 17- 403. 1. Nutrient credits must be purchased before plan can be approved. Please contact Ana Kilmer before purchasing the credits. Acknowledged. Nutrient credit availability letter has been added to the calculation book. Purchasing of nutrient credits will be coordinated with Ana Kilmer. Rev.1: Comment not addressed. Correspondence with Ana Kilmer has been initiated. 2. SWM Maintenance agreement must be recorded before plan can be approved. Please contact Ana Kilmer to start this process. Acknowledged. Rev.1: Comment not addressed. Correspondence with Ana Kilmer has been initiated. 3. A plat and deed showing the SWM facility easement must be recorded before the plan can be approved. Acknowledged. Rev.1: Comment not addressed. Location and label confirmed by County Planning and Engineering via email dated 1/30/20. This plat will be provided once obtained. 4. Clearly show the extent of the SWM Facility easement. Stormwater Easement Plan has been added. See Sheet C2.3. Rev.1: Please label this easement to be SWM facility easement. Ensure this matches the final site plan. Callouts have been updated accordingly. See Sheets C1.0 & C2.3. S. Provide a detail of the SWM facility. Will there be a trash rack? What size are the manholes/openings? Are they accessible for maintenance? Are there any special installation instructions? Site specific detail of SWM A to be provided once received. Rev.1 Comment not addressed. Shop drawings for the proposed SWM facility, addressing these items, have been added to Sheet C1.C. 6. Provide maintenance requirements for the SWM facility on the plans. Detention Pipe Maintenance schedule has been added to Sheet C1.6. Rev.1: Comment addressed. 7. Provide the following checklist on the plans:. Checklist added to cover C0.0. Rev.1: Comment addressed. 8. Please double check all calculations. Page 7 of the calculations does not match Sheet C1.6 (1.03 vs 1.06 etc). Due to the removal of the proposed entrance from Route 29, areas have been updated and double checked. Rev.1: Comment addressed. 9. Please double check the DA for inlet 118. Drainage Areas have been updated per the plan changes. Rev.1: Comment addressed. 10. Are the storm pipes sized for the future development? It is clear the SWM facility was sized/routed for it, but the storm calculations do not appear to include the future area (the DA for 112 is 0.69 c factor for future building area). The pipe calculations for future development are not being performed at this time. They will need to be computed at the time of the future development design. The SWM facility has been sized for a conservative potential option so that the pipe will not need to be replaced. The details of how the inlet and pipe calculations would change with the future development are too specific to assume. Rev.1: Comment not addressed. The pipe and inlet calculations should include the future development if they will eventually handle runoff from that area. For example, 204-202-SWM A. Where will the future development tie in? If it goes directly to SWM A, then no calculations necessary and comment is addressed. With the future development, the roof drainage will connect directly to SWM A. That new pipe will be analyzed with that proposed scope. 11.0.5% is the minimum storm pipe slope. The calculation shows some pipe slopes less than 0.5%. Pipes corrected to have a minimum slope of 0.5%. Rev.1: Comment not addressed. There is a slope of 0.49% from 101-102. The pipe calculations have been corrected. 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, 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. A soils type map was not apparent on the plans or in the calculation's booklet. All soil on site is type 91. A callout has been added to Sheet C1.4. Rev.1: Comment addressed. 2. Please show a wash rack at the construction entrance. A callout and the detail have been added. See Sheet C1.3. Rev.1: Comment addressed. 3. Please show mulching anywhere there is TS or PS. Mulching has been added to sheets C1.4 and U.S. Rev.1: Comment addressed. 4. Per PGIII-72 pf the VESCH, please show there is a 2:1 length: width flow ratio for the sediment trap flow path. The sediment trap was reshaped, and a wood baffle was added to ensure a 2:1 flow ratio. See Sheet 1.4. Rev.1: Please add a detail for the proposed baffles and note that they must extend from the bottom of the trap to 6" above the riser. A Wood Baffle detail has been added to Sheet C1.3. 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. Sincerely, r,A ' ZZ�w2' Craig Kotarski, P.E. Principal