By: Caitlyn Capalongo
Capital Bikeshare is Washington D.C.’s bikeshare system that includes 700+ stations and 6,000 bikes located across the metro area. The program is working to expand access to bikeshare stations as a part of an ongoing effort to create safer, healthier, and more diverse communities. The stations are solar powered and use wireless technology to allow for easy installation. Individuals can pay, unlock, and ride an eco-friendly bike that will get them to their destination.
The installation of these bikeshare sites has created additional opportunities for stormwater management. Stormwater runoff, polluted by contact with impervious surfaces, carries harmful pollutants like oil, sediment, and litter flow through municipal separate storm sewer systems (MS4) and overland into waterways. Washington D.C.’s National Pollutant Discharge Elimination System (NPDES) permit for MS4s addresses this pollution through stormwater management techniques, such as Green Infrastructure (GI). GI practices like bioretention facilities, permeable pavement and other similar practices capture and filter runoff. GI is essential to limit harmful pollution to aquatic life. Additionally, GI helps keep D.C. visitors and residents safer by reducing excessive water buildup on roads and sidewalks.
Straughan Environmental, Inc. (Straughan) is working with Toole Design Group on a Capital Bikeshare Green Mobility Project. The goal of this project is to design and obtain approvals needed for the proposed stormwater management (SWM) best management practices (BMPs) that will be installed at identified bikeshare sites in Washington D.C. The type of BMPs proposed are site specific and depend on site conditions such as hydrology, topography, right-of-way, existing utilities, hydraulics, street trees, and soils characteristics.
Straughan is leading the development of drainage and SWM sizing calculations that show the contributing drainage area and impervious surface treated at each site. Permeable surfaces and streetside bioretention systems are the SWM BMPs used for this project, as they provide stormwater retention and generate Stormwater Retention Credits (SRCs). Straughan is leading the completion of D.C. Department of Energy and Environment (DOEE) SRC calculations.