04/04/2024 CONSERVATION COMMISSION Minutes

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The motion passes unanimously. 6:33 NOI 43-3275 0 Main St, Town of Mashpee, Department of Public Works. Proposed storm-water improvements to the existing boat ramp and parking lot. Rep: Horsley Witten Group, Inc. Resource Area: Buffer zone to inland bank, bordering vegetated wetlands & land under waterbodies/waterways (Mashpee Pond). Ms. Maura, from the Association of Preserve Cape Cod, starts with an introduction to the project. The initial project was funded through the EPA Snap or the southeast New England Program Grant which contracted the Horsley Witten Group to design the project. The proposal is for 20 different style boat ramps across Cape Cod with the main focus on the public as these areas are generally untreated from storm-water runoff. This in turn will help improve the water quality in neighboring bodies of water. With the assistance from the town of Mashpee as well as the office of fishing and boating access at the Mashpee Wakeby boat ramp the design is about 75% complete as of December last year. Horsley Witten Group has been working through permitting with private foundation fund through the spring. Ms. Veary, the lead designer for Horsley Whitten Group, outlined the project's objective: to enhance the water quality of the pond through green storm water infrastructure. She noted that the site, owned by the state and maintained by the town, experiences runoff from Fisherman’s Landing Road and a sizable paved parking lot leading directly to the pond. The primary aim of the design is to intercept and treat runoff from the parking lot before it reaches the drive aisle. To achieve this, the proposal involves regrading the parking lot to channel runoff to four bio-retention areas surrounding it. Additionally, two underground infiltration chamber systems are planned to manage larger storm events, with a fifth bio-retention area near the boat ramp to capture and treat runoff from the drive aisle. These chambers are sized to handle a 25-year storm, with excess overflow directed by spillways to the wooded area around the parking lot. Ms. Veary explained that the bio-retention area near the boat ramp is designed to address a 1- inch storm event, with larger flows continuing down the boat ramp. Restoration efforts include removing invasive species from the fifth bio-retention area, approximately 2,000 square feet, and replacing them with native plants, including those listed as culturally significant by the Wampanoag tribe. Additional site components include striping the speed table to function as a pedestrian crosswalk, promoting vehicle deceleration. Furthermore, recognizing the high foot traffic at the boat ramp, the proposal includes signage to educate the public. Ms. Ball, Senior Ecologist at Horsley Whitten Group, clarified two waivers associated with the project. Firstly, the project seeks a waiver for newly expanded buffer zones, as its design was finalized in November 2023, predating the grant funding received several months later through the EPA Snap program. Secondly, a waiver is required to conduct work within a 50-foot naturally vegetated buffer zone to accommodate one of the proposed five bio-retention areas.