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Response to SWPPP Comments 38 High Rock Avenue, Suite 3 | P.O. Box 272 | Saratoga Springs, NY 12866 | 518.450.4030 December 15, 2021 Craig Brown Zoning Administrator and Code Compliance Officer Town of Queensbury 742 Bay Road Queensbury, New York 12804 Email: CraigB@queensbury.net Re: Civitella Residence – 104 Knox Road, Town of Queensbury, Warren County, New York- SWPPP Review Comments Dear Mr. Brown: We are in receipt of The Chazen Companies’ review letter, dated September 23, 2021, pertaining to the above referenced project located in the Town of Queensbury, NY. It should be noted that since the original submission, the proposed architecture as well as the site plan have been modified to reflect a design more compliant to Queensbury’s Waterfront Residential zoning requirements within the dimensional bulk and area schedule. However, much of the layout remains similar. HydroCAD models and stormwater calculations have been updated to reflect the new conditions. With respect to the comments provided in Chazen’s letter please see the following responses: Comment 1: According to the site plan review application, the proposed site improvements will disturb less than one (1) acre and thus the project is not required to obtain coverage under the NYSDEC SPDES General Permit for Stormwater Discharges from Construction Activity (GP-0-20-001). However, this project falls within the Lake George watershed and therefore is subject to the stormwater management requirements set forth in Section 147-11 of the Town Code for projects within the Lake George Park. Comments related to the stormwater management and erosion and sediment control features proposed for the site are offered below: Response 1: No comment. Comment 2: According to the site plans, this project proposes land disturbance of less than 15,000 square feet and may be classified as a minor project for stormwater management by Town Code Section 147-11.E(1)(a). The Applicant has provided stormwater calculations for a twenty-five-year, twenty-four-hour storm event in lieu of the 1.5 gallons per square foot minor project calculation. Response 2: Both the twenty-five-year, twenty-four-hour storm event and the 1.5 gallons per additional square foot of impervious area were modeled. It was determined 1.5 gallons per additional square foot of impervious area was the criteria that was more difficult to attenuate. The project now attenuates for the twenty-five-year, twenty-four-hour storm event as well as the 1.5 gallons per additional square foot of impervious area. Comment 3: The Site Development Data on the Site Plan Application appears incorrect. Line G of the “Total sq. ft.” column does not equal the sum of the column. “Proposed addition sq. ft.” does not equal the sum either. Applicant to revise. Response 3: Totals revised. Comment 4: In the Stormwater Management Report, it does not appear that the elevations of the infiltration practices reflect the proposed conditions. Pond 7P has an invert of 329.50’. The profile of the paver/reservoir system would indicate that the surface of the paver is at an elevation of 331.00’ plus the height of the paver. Elevations shown on the site plans show no surface elevations within the practice exceeding ~330.75’. A similar error exists for ponds 3P,4P, and 6P. Applicant to revise model to reflect proposed conditions. Response 4: Model revised to reflect paver system more accurately. Comment 5: Areas of the paver system do not appear to agree between the subcatchment maps and stormwater model. Subcatchment 1S identifies 535 SF of porous pavers, and the same is measured on the proposed subcatchment map. However, only 355 SF of pavers are modeled for pond 4P. Other subcatchment paver areas do not correspond to the modeled paver area. Applicant to revise. Response 5: Paver areas revised. Comment 6: The site plans identify a section of driveway where the porous paver reservoir is lined with an impermeable membrane. Pond 7P is modeled with no infiltration; however, a section of driveway within the practice is shown on the plans as infiltrating. Applicant to revise. Response 6: Permeable pavers removed in this area. Comment 7: The Lake George Park Commission considers permeable pavers as “entirely impervious, with the infiltration device directly beneath. Minor project pavers must have a minimum 6” subsurface reservoir (6” stone @ 40% voids ~2.4” depth equivalent to 1.5 gal/SF. Further, for driving surfaces, a choker course is required for pretreatment with appropriate maintenance provisions included on the plans. Also, paver systems must have an overflow that will allow stormwater to enter the subsurface reservoir in the event of surface failure (eg, stone perimeter trench, drop inlet, etc.) If the system is receiving stormwater from adjacent impervious areas, it must be sided for the paver surface as well as any additional tributary area.” The application shows no overflow provisions for the paver system. Applicant to revise the paver system to include overflows. Response 7: Pavers revised to meet these requirements. Comment 8: Town Code section 147-11.I(2)(a) states that the “location of infiltration devices shall be determined based upon soil test results.” Only one test pit is located in an area of a stormwater infiltration device – no infiltration testing was performed within the bounds of a practice. The Applicant to perform soil test pits and infiltration testing within the bounds of each infiltration practice to confirm the soil’s infiltration capacity and verify that adequate vertical separation distances exist. The test pits and infiltration tests shall meet the standards prescribed in the NYS Stormwater Management Design Manual, Appendix D. Response 8: Test Pit 2 (TP-2) was performed in proximity to the permeable pavers (modeled as infiltration practice) and the rain garden (modeled as bioretention practice) to evaluate subsurface conditions within proximity of the proposed basin. Additionally, Percolation Test 3 (PT-3) was performed adjacent to TP-2 and results are assumed to be representative of conditions expected within the area pf the permeable pavers and rain garden. Supplemental soil testing and infiltration tests can be performed at the request of the Town to confirm soils present and depth to restrictive layers within basin areas prior to construction. Comment 9: Percolation test #3 was performed closest to the paver infiltration device surrounding the residence, and shows a stabilized infiltration rate of approximately 212 minutes per inch (0.28 inch/hr). Infiltration discarded from the paver system is modeled at 5.05 inch/hr. Applicant to revise the model to match field determined infiltration rate, or clarify if the infiltration rate was entered incorrectly. Response 9: There recorded infiltration rate was 11 minutes and 53 seconds per inch (or 5.05 inches/hour), the original submission was a typist’s error. Comment 10: Section 5.3.11 of the NYS Stormwater Management Design Manual (SMDM) states, “permeable pavement systems shall be separated by at least 100 horizontal feet away from drinking water wells and 25 feet downgradient from structures and septic systems.” The site plans indicate that the paver system is within 18 feet of the proposed well, and adjacent to the proposed residence. Applicant should revise to meet the SMDM. Response 10: The lakefront patio with permeable pavers will no longer be infiltrating stormwater to protect water quality of the well. Comment 11: In accordance with Town Code section 147-11.I(2)(c), the Applicant should depict neighboring septic absorption fields if they are within 20 feet of a proposed infiltration device. The Applicant shall depict neighboring water wells within a reasonable distance (200 feet), if applicable. Response 11: Prior to construction, Studio A staff will verify the location of neighboring water wells and septic absorption field to the extent possible. Comment 12: Table 1 from the NYSDOH Drinking Water Regulations Appendix 5B (Section 5-B.7) states the minimum separation distances between contaminant sources and water wells. Appendix 5B requires 50 feet of separation for surface water recharge absorption system with no automotive- related wastes. Based on the plans it does appear that all portions of the proposed infiltration practices are at least 50 feet from the proposed well. As a result, the Applicant shall revise the location of the stormwater management practices to demonstrate conformance to the NYSDOH regulations. To note, newly constructed wells are subject to NYSDOH review. Response 12: The lakefront patio with permeable pavers will no longer be infiltrating stormwater to protect water quality of the well. Comment 13: The Erosion and Sediment Control plans shall include the notes of section 147-11.J of the Town Code. Response 13: Sheet L-0.30 revised to include notes. Comment 14: The Applicant shall revise the silt fence detail provided to match the latest specifications provided in the NYS Standards and Specifications for Erosion and Sediment Control, to include the slope length/ fence length spacing requirements. Response 14: Silt fence detail on sheet L-5.10 revised. Included in this revised Site Plan Review Application please find a revised site plan drawing set and SWPPP. If you have any questions or comments, please do not hesitate to reach me at the office phone, (518) 832-4005, or email me at mhuntington@studioadpc.com. Yours truly, Kirsten A. Catellier, RLA, ASLA for Studio A | Landscape Architecture and Engineering, DPC