Overview

The United States Botanic Garden (USBG) together with the U.S. Environmental Protection Agency (EPA) wanted to reduce or eliminate stormwater flows from the USBG into combined storm and sewer infrastructure operated and maintained by the Washington Area Sewer Authority and collect stormwater to be re-used for irrigation at the USBG, lowering their annual demand 11.8 million gallons per year (mg/y) of water purchased. Furthermore, the USBG wanted to maintain and improve their position as a leader in both education and application of sustainable water practices by providing examples to the public to demonstrate sustainable design strategies and opportunities to use stormwater as a resource and promote green infrastructure in urban settings.

We studied the USBG’s facilities and recommended 16 stormwater management projects estimated to reduce water usage by 24.8% or 2.9 mg/y, while eliminating 137,000 sq.ft. of impervious surfaces throughout the campus and 12.8 mg/y of stormwater runoff from entering the sewer system.

Solution Details

In reviewing the water/sewer billing and operations at the USBG, and six years of average rainfall data, we estimated that 64.4% or 7.6 mg/y of potable water purchased was used for irrigation. Through recommended projects, the USBG could capture and re-use 2.9 mg/y of rainwater, saving over $25,000 per year in water/sewer bills.

Stormwater re-use and management technologies investigated and/or recommended were: