The project will install a passive storm water treatment system consisting of a series of bio-filtration swales and water quality manholes along the length of the marina parking lot to filter runoff before it enters the bay. Work will:
• Excavate up to 1, 000-foot long trench, approximately 6 feet deep and 5 feet wide, or approximately 1,200 cubic yards.
• Excavate up to five, 4-foot diameter manholes for treatment of runoff that does not drain toward the bio-swales.
• Excavate and install approximately one 4-foot diameter sedimentation catch basin for unpaved areas.
• Install up to 1,000 feet of 6-inch diameter under-drains, and 100 feet of 18-inch culverts.
• Install filter media in trench to a depth of up to 4 feet.
• Install soil, plants, and rocks above the filter media.
• Install an asphalt overlay on the existing parking lot to direct most of the storm water to the biofiltration swales.
• Rebuild eroded slopes to support the bio-filtration swales.
• Trench to a depth of 18 inches for approximately 200 feet of electrical conduit for future electric vehicle charging stations.
• Repair and construct up to 250 feet of curbs to contain and direct runoff.