George Washington University
OP-27: Rainwater Management

At this time GW has four locations where we retain and reuse storm water (SEH, MISPH, Law Learning Center, Sq 80 Plaza). Green roofs: Elliott School (1,596 sf), Ames Hall (2,388 sf), Law Learning Center (1,200 sf), Milken Institute School of Public Health (MISPH) = Total 11,044 sf Permeable paver Sq. 80 Plaza. List of locations with native plants (no irrigation) - 11 LEED buildings.

Four stormwater goals from the GWater Plan are as follows: 1) Use GW campuses as test beds for new water reclamation technologies to reduce potable water consumption; 2) Capture rainwater that falls on GW campuses aiming for zero run-off, 3) 10 percent absolute increase in permeable space over 10 years from FY11 baseline, and 4) By 2021 reuse all retained stormwater for graywater systems, cooling towers, and irrigation.

During the performance year, rainwater harvesting was performed at three locations (Sq 80 Plaza, Law Learning Center, MISPH). Rainwater was reused at all these locations for irrigation and at MISPH for flushing toilets and as cooling tower make-up water. Additionally, three locations (Sq 80, 2110 G St, and 2131 G St) use rain barrels to collect rainwater for irrigation (total capacity of 415 gallons). These locations do not at this time have meters but the answer to the next question regarding volume of rainwater reused is based upon the capacity of the cisterns and our best estimates of the amount reused.

GW began installing water treatment systems for stormwater in 1996. GW now has 14 of these devices in 13 buildings. In addition to treatment, several of these systems include storage basins similar to storage ponds but located below grade rather than on grade. All of them slow the rate at which storm water enters the sewer system and they remove solids from the storm water before discharge. GW’s Law Learning Center contains a Stormceptor treatment manhole, a 16,500 gallon detention cistern, and a 6,000 gallon irrigation cistern. Stormwater from most of the site is drained to the 16,500 gallon detention cistern, where stormwater is held for detention prior to discharge into the combined sewer system. Unless this cistern is at full capacity, the stormwater is redirected to a Stormceptor for separation of oils and sediments prior to discharge into the combined sewer system. (If the cistern is at capacity, water would bypass the Stormceptor and discharge directly into the combined sewer system.) A portion of the site’s rain water is collected in a 6,000 gallon irrigation cistern located at the opposite end of the site, where the water is held until it is redirected to a treatment system prior to release for irrigation."

The University's first green roof was installed on the Elliott School building (1957-1959 E St) in October 2008; it is approximately 1,600 square feet (sf) in size. In 2011, GW instaled a 2,388 sf green roof at Ames Hall and 20,900 sf at the building complex on Sq 54. The university added a 1,200 sf green roof at GW's Law Learning Center, designed 5,860 sf of green roof at the Milken Institute School of Public Health in 2014, and 10,150 sf of green roof on the future Science and Engineering Hall scheduled to open in 2015. There is also a small green roof on the President's house.

Much of the university's property is located in an urban area, with city-owned asphalt streets and impervious concrete sidewalks. The university has been making its own sidewalks more permeable and plans to continue to do so. The GWater Plan calls for a 10 percent absolute increase in permeable space over 10 years from an FY11 baseline. There are also porous pavers in the LEED Sustainable Site on GW's campus (see below for more detail) on Square 80. Streetscape Plan also calls for pervious paving between tree boxes along the curb in front of each building.

At this time the University uses three stand-alone rain barrels at Sq 80 plaza (300 gals), 2110 G St (50 gals), and 2131 G St (65 gals). A few downspouts are also connected to underground cisterns at Sq 80 plaza. At the Milken Institute School of Public Health all storm water is collected for reuse unless the cistern is full during a rain event.

The University's first rain garden was installed on the Square 80 Plaza. Another one is being planned for the Mount Vernon Campus.

While not directly installed by the university, a large detention basin was installed by Loudoun County near the parking lot of Enterprise Hall at the University's Virginia Science and Technology Campus specifically to serve the University's grounds.

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The university also has a certified LEED Sustainable Site which was a former parking lot, now a green space, with a rain water collection system and rain barrels to irrigate the grass and plants, and for source water for a fountain. As part of the project planning and management process, the GW Operations Team seized the opportunity to make GW’s urban campus even more environmentally friendly. They embarked on a process to create a plaza in the interior middle of the city block (Square 80) between the surrounding buildings. The vision was to create a space that would be beautiful, enjoyable, and acts as an urban resource that protects the Potomac Watershed. Permeable brick pavers include an under-tray system used to collect rainfall. Three below-ground cisterns totaling 33,000 gallons hold the rainwater. Runnels capture non-permeable hard-scape run-off and direct it into tree pits and planters. Rooftop water is diverted from adjacent buildings into the cistern system. Where parking is required by zoning laws, Grass-Pave™ is installed and planted with Buffalo grass. All plantings are native (70%) and adapted (30%) species, further reducing water demand. The fountain draws from the cistern system, and auto shuts-off when the water supply runs low. Stormwater management devices have been required in Washington, DC for new development projects since the mid-1990s. The university has 13 buildings using a total of 14 stormwater treatment devices. In addition to the treatment system, some of these also include large storage basins similar to storage ponds but located below grade rather than on grade. All of them slow the rate at which stormwater enters the sewer system and they remove solids from the stormwater before discharge. The GW Law Learning Center has two cisterns (8k gallon and 16.5k gallon) in place. At two new construction sites, the Milken Institute School of Public Health and Science and Engineering Hall, GW will be reclaiming stormwater from roof drains for use in flushing toilets and urinals and for cooling tower make-up.