Case Study of Comprehensive Environmental Regulations in the District of Columbia

Washington D.C. encompasses 68.34 square miles, with approximately 42% impervious area. This highly urban setting can create substantial stormwater and environmental issues. The District of Columbia’s Department of Energy and Environment (DOEE) is the lead agency for environmental regulations in the District. It has developed various programs aimed to increase the quantity and quality of environmental performance of the urban landscape. The Stormwater Rule requires major substantial improvements and major land disturbing activities to retain the volume from a 0.8-inch storm event and a 1.2-inch storm event, respectively. This Stormwater Retention Volume (SWRv) can be managed through various types of BMPs, such as bioretention, permeable pavement, and green roofs. In addition to the stormwater requirements, DOEE developed a stormwater trading program called the Stormwater Retention Credit (SRC) program. Stormwater “credits” can be generated and sold to earn revenue for projects that reduce harmful stormwater runoff by installed green infrastructure or by removing impervious surfaces. Both the Stormwater Regulations and the SRC Program emphasize retention in the MS4. DOEE also manages the Green Area Ratio (GAR) program, which is an environmental sustainability zoning regulation that sets standards for landscape elements and site design that contribute to the reduction of stormwater runoff, the improvement of air quality, and the mitigation of the urban heat island effect. While many stormwater practices can also meet GAR, GAR adds additional layers of environmental benefits above stormwater. Elements that can count towards GAR include bioretention, green roof, landscaped areas, vegetated walls, renewable energy, and native plant selection.