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HomeMy WebLinkAboutWPO202100059 Correspondence 2022-06-10608 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 June 10, 2022 David James County of Albemarle Community Development 401 McIntire Rd, North Wing Charlottesville, VA 22902 RE: Crozet Self Storage — VSMP Permit Plan Review (Rev. 2) — W P0202100059 - Comment Response Letter Dear Mr. James: We have reviewed all of your comments from May 11, 2022 (Rev. 2) 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. Please submit the SWPPP. SWPPP has been included in this submittal. (Rev. 1): Addressed. 2. (Rev.1): Cover —Add WPO number. WPO number has been added to the SWPPP cover. (Rev. 2): Addressed. 3. (Rev.1): Registration Statement— Complete & sign. Registration statement has been signed and completed. (Rev. 2): Addressed. 4. (Rev.1): Complete Section 9 prior to plan approval. Section 9 has been signed and completed. (Rev. 2): Addressed. 5. (Rev.1): Complete other sections prior to pre -con. LNGINLLRING I DLSIGN i TLCHNOLOGY You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) Additional information will be added to SWPPP as it becomes known. (Rev. 2): Acknowledged. B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code section 17-404. 1. Please submit with the SWPPP. SWPPP has been included in this submittal. (Rev. 1): Addressed. 2. (Rev.1): Show SF around stockpile area. Silt fence has been added around stockpile area. (Rev. 2): Addressed. 3. (Rev.1): Provide concrete washout detail of containment. Concrete washout area detail has been added. (Rev. 2): Addressed. 4. (Rev.1): Provide mortar mixing station detail of containment. Mortar mixing containment area detail has been added. (Rev. 2): Addressed. C. Stormwater Management Plan (SWMP) VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is denied, 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. Show the building's roof drain connection(s). Acknowledged. Roof drain locations will be shown in next submittal. (Rev. 1): Not addressed. Roof drain leaders have been added to Grading and Drainage Plan, sheet C6.0. (Rev. 2): Acknowledged. It appears that the roof drain system ties into str. 302 based on the drainage area map provided. If so, see comments D11 & 12 below. Roof leader has been revised to show connection point to building, adjacent to loading bay entrance. Roof drain ties to inlet 302, see comments D11 & 12 below. 2. It appears discharge from the site will enter an impaired waterway. The first assessed waterway appears to be Lickinghole Creek. If so, it is ok to purchase nutrient credits from within the HUC 02080204, if credits are available. Acknowledged. (Rev.1): Acknowledged. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) Acknowledged. Nutrient credit letter of availability included in the Design Calculations & Narrative book is from the Ivy Creek Nutrient Bank, located in HUC 02080204. 3. Please provide Letter of availability from the nutrient provider on the plans and the HUC they're in. Letter of availability will be included in the next submittal. (Rev.1): Not addressed. Nutrient credit letter of availability has been included in the Design Calculations & Narrative book. (Rev. 2): Not able to locate. Nutrient credit letter of availability has been added to the Design Calculations & Narrative book; see section B. 4. Please record the SWM maintenance agreement prior to plan approval. SWM maintenance agreement will be recorded upon preliminary approval. (Rev.1): Not addressed. SWM maintenance agreement will be recorded upon preliminary approval. (Rev. Y22): Not addressed. Coordination of SWM maintenance agreement is underway with Ana Kilmer. 5. Provide lining (type) requirements for constructed channels. (Rev.1): Not addressed. Ditches have been labeled as grass -lined. (Rev. 2): Please include the channel cross -sections or a typical section with the appropriate lining & dimensions labeled. Ditch sections have been added to sheet C6.2. 6. Provide concrete inlet shaping (IS-1) on any structure with a 4' or greater drop. (Rev.1): Currently addressed. All structures have less than 4' drop as currently proposed. 7. Pipe 207 (public) should be 15" min. diameter. (Rev.1): Provide 15" diameter for pipes 210 & 208. The pipes are considered 'public' as it carries stormwater from offsite and VDOTs ROW through the site and therefore needs to be 15". [ACDSM, p.14]. Pipes 208 and 210 have been revised to 15" HDPE. (Rev. 2): Revise size to 15" dia. For pipes 209 & 207 (public). Str. 210 to 200 (end) & 101 is considered public. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) All 200-series and 100-series pipes were included as minimum 15" diameter in previous submittal. No change. 8. Size storm inlet 208 & 100 (DI-1) for half -clogged condition. [VDOT DM] (Rev.1): Provide for inlets 204. You may want to consider for inlets 100, 210 & 402. Calculations for inlets 100, 204, 208, 210 & 402 have been revised for a half -clogged condition. (Rev. 2): Acknowledged. 9. Show SWIM Facility Easement for basin. (Rev.1): Addressed. 10. Locate trees outside of drainage easements and basin embankment. (Rev.1): Not addressed. Storm line from Str. 210 to 200 is considered public with a 20-ft wide minimum easement and trees will need to be removed. Easement along storm line from structure 210 to 200 has been revised to 20' wide. Landscaping has been relocated to avoid widened easement. (Rev. 2): The trees & shrubs within 20' buffer of embankment will need to be removed. Trees and shrubs have been removed from stormwater maintenance easement. 11. (Rev.1): Sheet 7.0: Show the HGL in the profiles. Hydraulic grade lines have been added to profiles. (Rev. 2): Add note to provide water -tight seals/joints where HGL is above pipes and at connections between dissimilar material types. Note has been added to all storm profiles that all joints between pipes and structures shall be water -tight. 12. (Rev.1/2): Note: Currently'7TP credits to be purchase prior to WPO bond request. Current design requires 1.40 TIP credits, which is reflected in the nutrient credit letter of availability. Currently needs 1.40 Ib/yr TP. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) 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. Cover: a. Add WPC# under title. WPO number will be added in the next submittal. (Rev. 1): Not addressed. WPO number has been added to cover sheet. (Rev. 2): Addressed. b. Remove signature panel (not needed for WPO plan approval). Signature panel will be removed in the next submittal. (Rev. 1): Not addressed. Signature panel has been removed from the cover sheet. (Rev. 2): Addressed. 2. Sheet 3.0: The narrative, sequence should mention the cleanout and conversion of sediment trap to a permanent basin. Removal of sediment trap is included in Phase II item #5. Additional information regarding cleanout and conversion will be included in the next submittal. (Rev. 1): Not addressed. Phase II sequence item #5 has been revised to clarify that accumulated sediment shall be removed and the sediment trap shall be converted to the approved stormwater management facility. (Rev. 2): Acknowledged. Revise as necessary to account for area(s) draining to phase 2 sediment trap. Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been added to plans, and sediment trap has been calculated as sediment basin. Updated interim drainage area has been shown on sheet C3.3. Additional information regarding the conversion of the temporary basin to a permanent dry pond has been added to the Sequence of Installation on sheet C3.0. 3. There appears to be 2+ acres drainage area that is not going to the sediment trap (ST1) and rather the drainage is divided between the two existing culvert inlets to the south. a. Please verify the area going to the silt fence first (no more DA than % acre per 100 LF). [VAESC HB, 3.051 (Rev. 1): Not addressed. A diversion dike has been added to ensure that area flowing to silt fence does not exceed 100 LF. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) (Rev. 2): Addressed. b. May need to show diversion to IP or trap. Drainage area to the silt fence and existing inlet on the west side of the site will be reevaluated in the next submittal. (Rev. 1): Not addressed. A diversion dike has been added to ensure that area flowing to silt fence does not exceed 100 LF. (Rev. 2): Addressed. 4. Sheet 3.3: a. Label the inlet and/or sediment traps for this phase. Provide design & details. No sediment traps are included on Phase 11. Label will be added on the next submittal, indicating that the dry pond will be in place. (Rev. 1): Not currently addressed. The trap for ESC phase II will need to remain until conversion, so it still needs to be labeled and shown. The trap appears to be acting as a SB this phase with the riser & spillway present. Provide SB design & details if so, or ST #2 design & details for this phase. Erosion & Sediment Control approach has been revised per May 31 meeting, with the riser structure installed during Phase I to allow the facility to function as a sediment basin and to add and interim E&S phase with a dewatering structure during basement excavation. Sediment basin design calculations have been added to see C3.0. A note has been added to sheet C3.4 (sheets renumbered to account for new interim E&S phase) to indicate that the sediment basin shall remain functional until all contributing drainage area has been stabilized, before converting to the permanent stormwater management facility. Because the E&S Phase III drawings are intended to show the various measures that are installed and/or removed over the course of Phase III, the permanent dry pond is shown graphically on this plan sheet. (Rev. 1): Acknowledged; I believe you will need to account for the additional drainage area (greater than lac) to sediment trap, and ST #2 design or alternative would be necessary. See comment D11 & D12. Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been added to plans, and sediment trap has been calculated as sediment basin. The new Phase II plan also includes dewatering the building's basement excavation through a Dirtbag sediment filtration device to account for the additional area disturbed during this phase. b. Show OP from pipe into basin. Outlet protection will be added in the next submittal. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) (Rev. 1): Not addressed. Outlet protection has been added. (Rev. 2): Addressed. c. Provide B/M for west slope. [VAESC HB, 3.36] Grading has been revised, and no longer exceeds 3:1. (Rev. 1): Acknowledged. d. (Rev. 2): Provide low -maintenance ground cover (not grass) specified on the plans for the slopes highlighted or reduce slopes to be 3:1 or less. Low -maintenance ground cover has been provided for slopes exceeding 3:1. 5. Provide 5' (min) distance between bottom of slope and silt fence (or diversion) placement. [VAESC HB, 3.05; ACDSM]. As a result of the updated site configuration, silt fence is no longer required along the west side of the site and has been removed accordingly. (Rev. 1): Not addressed. (Rev. 2): Addressed. 6. Show offsite work in an easement. Temporary construction for offsite work will be included in the next submittal. (Rev. 1): Not addressed. Temporary construction easements have been added for offsite work. a. Obtain VDOT entrance permit prior to land disturbance. VDOT entrance permit will be obtained prior to land disturbance. (Rev. 1): Not addressed. Entrance permit has been submitted to VDOT and is under review. (Rev. 2): Acknowledged. 7. Provide cut/fill volume estimate. Cut/fill report will be included in the next submittal. The current design intent is for the site to balance when accounting for pavement sections and building foundation. (Rev. 1): Not addressed. Cut/fill report has been included in the Design Calculations and Narrative book with this submittal. (Rev. 2): Acknowledged; adjust report as needed. Cut/fill report has been updated to reflect the current design in the Design Calculations and Narrative book. 8. (Rev.1): Show the drainage area of sediment trap. You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) Drainage divide to Sediment Trap #1 has been added to sheet C3.2. (Rev. 2): Addressed for ST#1. Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been added to plans, and sediment trap has been calculated as sediment basin. Drainage area during the new Phase II has been included on sheet C3.3. 9. (Rev.1): SF perimeter control should be placed here: Silt fence has been added to sheet C3.2 & C3.3. (Rev. 2): Addressed. 10. (Rev.1): Diversion perimeter control should be placed here: Grading has been revised to extend ditch to channelize runoff from area behind curb. (Rev. 2): Addressed. 11. (Rev.2): Sheet 6.3: Account for the roof drainage area as well in sizing pipe 301. Roof drainage area has been added to sheet C6.3 and included in the calculations for pipe 301. HGL on sheet C7.0 has been revised accordingly. 12. (Rev.2): Sheet 3.0, 3.2, 3.3: The area to sediment trap given does not account for the amount of area that will be draining to it during phase II. Please clarify & account for this area in the total volume needed for the design. Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been added to plans, and sediment trap has been calculated as sediment basin. The new Phase II plan also includes dewatering the building's basement excavation through a Dirtbag sediment filtration device to account for the additional area disturbed during You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) this phase. 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 clint.shifflett@timmons.com . Sincerely, Clint Shifflett, PE Project Manager You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com)