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HomeMy WebLinkAboutPresentaitonYarmouth Stormwater Retrofit Design and Implementation Project Curve Hill Stormwater Retrofit Public Hearing Yarmouth Conservation Commission MassDEP File No. 083-2450 October 3, 2024 *Funding for this work has been provided by Massachusetts Office of Coastal Zone Management Coastal Habitat and Water Quality Grants. agenda 1.Existing Conditions/Resource Areas 2.Proposed Conditions 3.Resource Impacts 4.Q/A Project Goal To improve coastal water quality by reducing or eliminating pollution (bacteria and nitrogen in particular) from stormwater runoff 10 Priority Sites Advanced 5 Sites: •HIH-3 Grove Street •MC-3 Standish Way •MC-5 Baker Ave •PR-3/4 Lake Rd West •UBR-4 Curve Hill Road Site Location UBR-4 Curve Hill Existing Conditions •Total Drainage Area = 13.0 ac •32% Impervious (4.14 ac) •Great Western Road drainage infrastructure •Surface runoff from Curve Hill Road UBR-4 Existing Conditions •Large undeveloped Town parcel •Receives surface and piped flow •Evidence of accumulated sediment •Existing Stormwater Infrastructure •Large drainage area with no treatment •Freshwater Wetland downgradient Proposed Conditions •Constructed Wetland for Treatment •Collects runoff from both existing drainage infrastructure and surface runoff from road •Water quality unit for pretreatment (yellow) •Discharges treated stormwater to the existing freshwater wetland (green) Constructed Wetland •Remove pollutants through wetland vegetation uptake and settling •TSS: 80% •Total Phosphorous: 40-60% •Total Nitrogen: 20 to 55% •Temporarily store runoff in shallow to deep pools •Enhances aesthetics of the site •Supports habitat Resource Areas •35-ft Buffer Zone to BVW (red dashed line) •50-ft Buffer Zone to BVW (blue dashed line) •100-ft Buffer Zone to BVW (green dashed line) Coastal Resource Area Impacts Resource Area Impact (SF)Nature of Impact 35-50-foot Buffer Zone to BVW 370 Rip-rap 50-100-foot Buffer Zone to BVW 3,250 Rip-rap, Constructed Wetland Resource Area Impacts The proposed project will improve conditions: •Project components improve the ability of resource areas to perform their function to protect the interests of the state and local wetland regulations. The project is restorative in nature and will provide an overriding public, environmental, and health benefits through the improvement of the water quality in Bass River watershed. Thank You! Questions?