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HomeMy WebLinkAboutNarrative Revised 2.1.2022Ryt &Wilcox 3 GIDDIAH HILL ROAD P.O. BOX 439 SURVEYING • ENGINEERING SO.ORLEANS, MASSACHUSETTS 02662-0439 HOME PLANNING. & DESIGN TEL: 508.255.8312 FAX: 508.240.2306 EMAIL: in&@ryder-wilcox.com PROJECT NARRATIVE PYTHON/LOUGHMAN PROPERTY 31 GRISTMILL LANE January 26, 2022 Rev. 2/1/2022 (Performance Standards) Property Description The property is a 9504+/- SF developed site. The property overlooks Mill Creek (tidal) and is separated from the creek by Mill Creek Lane, a paved road. A salt marsh lies adjacent to the waters of Mill Creek and extends onto the Site. The entire site is also designated as Land Subject to Coastal Storm Flowage (Zone AE, El 11 and El 13 - NAVD 1988). The 35', 50' and 100' Buffers are measured from the landward edge of the salt marsh. The Riverfront (approximately 9504 SF) extends 200' landward of mean high water; An existing one-story single-family dwelling with deck and drive -under garage lies approximately 17.6 feet from the marsh. According to Assessors records, the dwelling was built in 1963 and contains three bedrooms. The Riverfront/Buffer/LSCSF is developed with lawn, plantings, and hardscaping including a brick walkway, concrete retaining walls and a paved driveway. The square footage of existing buildings and hardscaping within the Riverfront is approximately 3370 SF: The existing Title 5'septic system serving the dwelling was upgraded in 2004 and consists of a 1500-gallon septic tank and 1000-gallon pump chamber discharging to a mounded leaching field. A 2016 Title 5 Inspection of the system found no evidence of failure. The property is served by Town water. Project Description' The Applicant proposes to remove the existing one-story building, including the foundation, and construct a new two-story building on a poured concrete foundation with a front porch and steps constructed on sonotubes. The proposed building is located approximately 14.4' from the marsh. The new structure is located entirely within the footprint of the existing developed area. The net increase in roof area is 502 SF. The first floor of the proposed dwelling will be elevated above the 100-year flood elevation in accordance with FEMA requirements. The dwelling will remain three -bedrooms and will be connected to the existing septic system. The existing paved driveway and retaining walls (approximately 1224 SF) will be removed and replaced with a new, smaller driveway (approximately 496 SF) constructed of pervious material and located on the opposite side of the property, further from the marsh. The existing brick walkway will be removed. A comparison of the existing/proposed coverages within the various buffers is illustrated on the attached "Coverage Calculation Worksheet", and is as follows: Within the 35' Buffer, the habitable area increases by 119 SF. The total coverage is reduced by 931 SF. - Within the 35' — 50' Buffer, the habitable area increases by 8 SF. The total coverage increases by 288 SF. - Within the 50' - 100' Buffer, the total coverage increases by 36 SF. - The proposed project will result in an overall reduction in coverage (-606 SF) The proposed project will result in an overall reduction in coverage (-606 SF) within the Riverfront. (See attached Riverfront Coverage Worksheet.) As mitigation for the proposed work, native plantings are proposed within the 50' buffer to the marsh. Approximately 1600 SF of existing lawn/paved driveway area will be restored with native plants. The remaining lawn area will be restored with loam and a drought -tolerant native fescue grass mix. CONSTRUCTION PROTOCOL PHASE 1 — REMOVAL OF EXISTING STRUCTURES The project engineer shall stake the location of the approved limit of work. A fabric siltfence shall be securely staked in place along the limit of work. The siltfence shall remain in place until all disturbed areas have been stabilized and revegetated. The existing septic system components shall be adequately protected to prevent damage from construction activities. The existing building, deck, foundation and all hardscaping will be removed. Access to the work area shall be from the existing driveway. An excavator will demolish the structures, placing the debris either into a dumpster or directly into trucks to be hauled off -site. The dumpster shall be provided with a suitable cover or be of adequate depth to prevent wind-blown debris. PHASE II — PROPOSED DWELLING After the demolition and removal of the existing structures, the project engineer shall stake the proposed foundation for excavation. All excavated material shall be immediately placed into trucks and removed from the site. There shall be no stockpiling of material on -site. The project engineer shall re -stake the foundation "in the hole" and after the footings are poured. A durable, waterproof tarp (or other suitable material) shall be placed in the driveway and shall be used to contain any concrete overpour. The tarp and hardened concrete shall be removed from the site and properly disposed. Throughout construction, all debris shall either be placed in a dumpster or other suitable container; the site shall be cleaned of debris on a daily basis. The proposed building will be connected to the existing septic system. An impervious barrier shall be installed along the exterior of the foundation as shown on the Proposed Site Plan. New utilities shall be installed as shown on the site plan. Gutters and downspouts connected to drywells or crushed stone at the roof dripline will be installed to contain roof runoff. Upon completion of backfilling and grading, all disturbed areas shall be revegetated. The new driveway shall be constructed of pervious material. ALTERNATIVES ANALYSIS The goal of the project is to provide additional, updated living space. As the existing dwelling, constructed nearly 60 years ago, lies entirely within the Riverfront, construction within the Riverfront is unavoidable. In order to minimize the disturbance within the Riverfront, the proposed building is located as far landward as is possible without further encroaching on the existing septic system. The proposed structure and hardscaping are located entirely within existing altered area. The net increase in roof area is 502 SF, including an additional 127 SF of habitable footprint within the 50' Buffer. As mitigation for the proposed increases, the existing paved driveway is being removed and replaced with a smaller pervious driveway. Native plantings are proposed within the 50' buffer to the marsh. Approximately 1600 SF of existing lawn/paved driveway area within the Riverfront will be restored with native plants. The remaining lawn area will be restored with loam and a drought -tolerant native fescue grass mix. PERFORMANCE STANDARDS 310 CMR 10.32 Salt Marshes (3) A proposed project in a salt marsh, on lands within 100 feet of a salt marsh, or in a body of water adjacent to a salt marsh shall not destroy any portion of the salt marsh and shall not have an adverse effect on the productivity of the salt marsh. Alterations in growth, distribution and composition of salt marsh vegetation shall be considered in evaluating adverse effects on productivity. 310 CMR 10.32(3) shall not be construed to prohibit the harvesting of salt hay. The proposed work shall be confined to the westerly side of the existing paved road and within the Limit of Work/Fabric Siltfence shown on the Site Plan. During construction, the installation of the siltfence shall serve as a physical barrier to prevent damage to the salt marsh. Post -construction, the control of roof runoff and the restoration with native mitigation plantings will provide improved protection to the salt marsh. (4) N.A. (5) N.A. (6) Notwithstanding the provisions of 310 CMR 10.32(3) through (5), no project may be permitted which will have any adverse effect on specified habitat sites of Rare Species, as identified by procedures established under 310 CMR 10.37. The project site is not located in Estimated Habitat of Rare Wildlife. 310 CMR 10.58 Riverfront Area (5) Redevelopment Within Previously Developed Riverfront Area: Restoration and Mitieation. Notwithstanding the provisions of 310 CMR 10.58(4) (c) and (d), the issuing authority may allow work to redevelop a previously developed riverfront area, provided the proposed work improves existing conditions. Redevelopment means replacement, rehabilitation or expansion of existing structures, improvement of existing roads, or reuse of degraded or previously developed areas. A previously developed riverfront area contains areas degraded prior to August 7, 1996 by impervious surfaces from existing structures or pavement, absence of topsoil, junkyards, or abandoned dumping grounds. Work to redevelop previously developed riverfront areas shall conform to the following criteria: (a) At a minimum, proposed work shall result in an improvement over existing conditions of the capacity of the riverfront area to protect the interests identified in M.G.L. c. 131 Section 40. When a lot is previously developed but no portion of the riverfront area is degraded, the requirements of 310 CMR 10.58(4) shall be met. The existing impervious surface area, consisting of paved driveway, building; and brick/concrete hardscaping, is 3114 SF within the Riverfront. The proposed impervious surface area, consisting of building (roofed) area, is 2081 SF, for a 1033 SF reduction. Additionally, existing lawn area adjacent to the Resource Area will be restored with native plants. These measures serve to improve the capacity of the riverfront area to protect the interests identified in the Act. (b) Stormwater management is provided according to standards established by the Department. The existing paved driveway is being replaced with a smaller, pervious driveway located further from the Resource Area. Roof runoff from the proposed building shall be contained through the use of either gutters and downspouts to drywells or crushed stone at the roof dripline. (c) Within 200 foot riverfront areas, proposed work shall not be located closer to the river than existing conditions or 100 feet, whichever is less, or not closer than existing conditions within 25 foot riverfront areas, except in accordance with 310 CMR 10.58(f) or (g). The proposed building is located slightly seaward of the existing structure and within 100' of the river. The existing structure (building, deck and steps) within 100' is 1216 SF. The proposed structure (building, porch and steps) within 100' is 1696 SF, for a 480 SF increase. The removal of 1224 SF of paved driveway and replacement with 496 SF of pervious driveway provides 728 SF of restoration, exceeding the 1:1 ratio required in accordance with 310 CMR 10.58(f). (d) Proposed work, including expansion of existing structures, shall be located outside the riverfront area or toward the riverfront area boundary and away from the river, except in accordance with 310 CMR 10.58(f) of (g). The proposed building is located slightly seaward of the existing structure and entirely within the riverfront. It is not possibly to locate the proposed structure closer to the riverfront boundary due to the presence of the existing septic system. The existing structure (building, deck and steps) within the riverfront is 1862 SF. The proposed structure (building, porch and steps) within the riverfront is 2268 SF, for a 406 SF increase. The removal of 1224 SF of paved driveway and replacement with 496 SF of pervious driveway provides 728 SF of restoration, exceeding the 1:1 ratio required in accordance with 310 CMR 10.58(f). (e) The area of proposed work shall not exceed the amount of degraded area, provided that the proposed work may alter up to 10% if the degraded area is less than 10% of the riverfront area, except in accordance with 310 CMR 15.28(5)(f) of (g). The existing impervious surface area, consisting of paved driveway, building, and brick/concrete hardscaping, is 3114 SF within the Riverfront. The proposed impervious surface area, consisting of building (roofed) area, is 2081 SF, for a 1033 SF reduction. All proposed work lies within the existing developed area and will not disturb any native vegetation. (f) When an applicant proposes restoration on -site of degraded riverfront area, alteration may be allowed notwithstanding the criteria of 310 CMR 10.58(5)(c),(d), and (e) at a ratio in square feet of at least 1:1 of restored area to area of alteration not conforming to the criteria. Areas immediately along the river shall be selected for restoration. Alteration not conforming to the criteria shall begin at the riverfront area boundary. Restoration shall include: 1. Removal of all debris, but retaining any trees or other mature vegetation; 2. Grading to a topography which reduces runoff and increases infiltration; 3. Coverage by topsoil at a depth consistent with natural conditions at the site; and 4. Seeding and planting with an erosion control seed mixture, followed by plantings of herbaceous and woody species appropriate to the site; As noted above, the removal of 1244 SF of paved driveway and replacement with 496 SF of pervious driveway provides 728 SF of restoration, exceeding the required 1:1 ratio of restored area to area of alteration not conforming to the criteria. The disturbed areas are to be loamed and seeded with a drought -tolerant fescue seed mix. Additionally, an area of approximately 1600 SF adjacent to the Resource Area will be restored with native herbaceous and woody plant species. (g) N.A.