07/25/2024 CONSERVATION COMMISSION Minutes

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The small lot is located in the Popponesset area, within 150 ft of a coastal dune. Part of the lot falls within the 75 ft buffer zone. The existing property will be removed and replaced. Lot Details: 1. Most of the lot is within a shallow area between 6 ft to 7 ft, requiring a raised septic system to position the bottom of the system at 5.5 ft above the mean groundwater level. 2. A new FA septic system will be installed. The groundwater is at an elevation of 1.2 ft, necessitating a retaining wall around it. 3. The only existing vegetation on the lot is a 14-inch Eastern Red Cedar tree. To preserve the tree, the retaining wall has been minimized around the raised septic leaching system. 4. The design includes a curve to keep the wall as far from the tree as possible, meeting the 10 ft requirement from the back of the retaining wall. 5. Fill is required in and around the septic system and behind the retaining wall. Proposed Dwelling: 1. The proposed dwelling will be at an elevation of 13.1 ft, compared to the existing 11 ft. 2. The dwelling will include flood vents and drywells. 3. The proposed porch will be on sonotubes. 4. The septic tank and pump chamber will be located in the front yard,pumping to the septic system in the back to ensure proper function. 5. A gravity system is not feasible due to the inability to make the walls 4 ft high without being set back 5 ft from the lot line. Existing vs. Proposed: 1. Existing house: 3 bedrooms 2. Proposed house: 3 bedrooms 3. Square footage increase: 287 sq ft 4. Existing driveway: cobblestone 5. Proposed driveway: gravel Mitigation: 1. Mitigation efforts will occur between the 75 ft and 150 ft buffer zones, with some extending beyond the 150 ft buffer. 2. The mitigation area is at an elevation of 6.5 ft. Waiver Requests: 1. Regulation 25 (C)(7)(C) — Setback 2. Regulation 25 (C)(4)(C) —Vertical walls Nitrogen calculations have been noted in the narrative/plan 13