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HomeMy WebLinkAboutWPO202100045 Correspondence 2021-12-06December 6, 2021 MEMORANDUM To: Mr. Matt Wentland, PE County of Albemarle, Virginia From: Mr. Eric Woolley, PE Woolley Engineering Regarding: Crutchfield Corporation Warehouse Expansion WPO202100045 (TM 32 P 9C) VSMP/WPO Plan Responses to comments from County Staff With this memo, we are responding to the comments that were directed to our office following the review of our VSMP/WPO plan for the Crutchfield Corporation Warehouse Expansion project located at 1540 Quiet Acres Lane. The comments were received in written format and dated September 23, 2021. Below, we have provided our responses to the correlated comments as numbered on your memo. A. Stormwater Pollution Prevention Plan (SWPPP) 1. The SWPPP containing a Registration Statement is attached to this memo. Signatures for the Registration Statement, Delegation of Authority, and Certification of SWPPP will be provided prior to plan approval. B. Pollution Prevention Plan (PPP) 1. A pollution prevention plan is now included within the SWPPP document. C. Stormwater Management Plan (SWMP) 1. Reference to this plan being an amendment to a previous plan have been removed from the relevant plan sheets. 2. The calculation to demonstrate compliance with the Energy Balance can be found in the Engineering Calculation Booklet attached to this memo. The point of analysis for the Energy Balance Equation was taken in the natural channel located directly downstream of the existing extended detention basin. 3. The grades for the basin have been revised to meet Albemarle County acceptance. A 3.5' tall retaining wall has been added to the basin area to allow for a 3:1 side slope for most of the basin. Per correspondence with County Engineering on October 11, 2021, the County has agreed that the existing embankment and standpipe structure can be preserved even though the existing slopes are greater than 3:1. 4. Stormwater Management As -Built requirement guidance has been added to the site plan on plan sheet C6.1. 5. Gravel diaphragms have been added to the plan as a secondary pre-treatment option for biofilters #2A and #2B in order to meet DEQ Specifications for a Level 2 biofilter. WOOLLEY ENGINEERING 210 5th Street NE (434) 973-0045 Charlottesville, Virginia 22902 WGGLLEY ENGINEERING Gutter system leaf screens have been added as a secondary pre-treatment measure for biofilter #1 to meet DEQ Specifications for a Level 2 biofilter. 6. There is a proposed forebay located near the entrance along Dickerson Road. This forebay is intended to pre -treat drainage from the existing parking lot on -site prior to entering the conveyance system and ultimately entering the extended detention basin. The adjacent properties have stormwater facilities on -site to treat their stormwater prior to entering our stormwater conveyance system. The required pre-treatment forebay storage for our extended detention basin as defined under the 2011 DEQ Specification # 15 totals 3,033cf of storage. This storage is being met by pre -treating a portion of the existing parking lot via the proposed forebay close to Dickerson Road, pre -treating the proposed parking lot via the forebay storage to be utilized for biofilters #2A and #2B, and pre -treating a portion of the existing parking lot and a portion of roof drainage via the proposed forebay to be utilized for biofilter #1. 7. The landscaping plan has been added to the plan set. D. Erosion and Sediment Control Plan (ESCP) 1. A narrative has been added to each E&S plan to clarify the order of work. I hope that these responses, in combination with the revised site plan have satisfied the deficiencies as noted in your comment memorandum. Please do not hesitate to call with any questions or concerns. Thank you for your time and consideration. Sincerely, Eric Woolley, PE Attached: (1) Electronic PDF Copy of the Revised VSMP/WPO Set (1) VSMP Application (1) Revised Stormwater Pollution Prevention Plan (1) Revised Engineering Calculation Booklet Cc: Bill Crutchfield, Crutchfield Corporation Bill Adams, Train Architects