DGS installs stormwater green infrastructure (GI) in all applicable projects. Project teams work closely with the Department of Energy and Environment’s Stormwater Management Division and DGS Facilities Management Division’s Environmental, Health, and Safety team (EHS) to limit the strain on municipal sewer systems, help recharge local aquifers, and reduce the quantity of pollutants entering the Anacostia and Potomac Rivers.
During heavy rains, stormwater runoff can overburden the sewer system and lead to raw sewage overflows to the Anacostia and Potomac Rivers. Green infrastructure is designed to absorb rainwater close to the source, filter it, store it, and in some cases, allow it to infiltrate into the ground. This process effectively maintains the site’s predevelopment hydrology cycle and prevents untreated runoff from entering the sewer system or nearby waterways. In doing so, green infrastructure support the city’s vision for restoring local ecology and managing flood risk.
Many different types of GI exist at District properties such as green roofs, bioretention cells or ponds, dry wells, greywater reuse, infiltration trenches, vegetated swales, cisterns, filter strips, sand filters, and more. Green roofs, in particular, are a critical component of the District’s efforts to capture stormwater, reduce the urban heat island effect, provide species habitat, and reduce building energy use by helping insulate roofs. A green roof is a rooftop that is partially or completely covered with vegetation planted in a growing medium over a waterproof membrane.