DC Firehouse Green Cubes
As part of its commitment to urban sustainability, the District Department of Energy and Environment (DOEE) installed two "green cubes" that both reduce the use of potable water and improve water quality in the Chesapeake Bay.
The below images are live renderings of each of the green cubes showing the collected water. What is unique about this rainwater harvesting system is the intelligent control based on the forecasted rainfall. OptiNimbus knows when a storm is predicted and releases water during dry weather to create capacity for the rainfall without overtopping.
Like many older communities in the Mid-Atlantic, Northeast, and Midwest, a portion of the District of Columbia is served by a combined sewer system (CSS). Approximately one-third of the entire sewer system is combined, mostly in the downtown and older parts of the city. In dry weather, the CSS delivers sewage to the Blue Plains Wastewater Treatment Plant. In wet weather, stormwater runoff from rooftops, roadways, and other impervious surfaces enters the CSS, and if the capacity of the system is exceeded, the excess flow (stormwater mixed with sewage) spills into the waterways surrounding the District. This discharge is called a combined sewer overflow (CSO).
The remaining two-thirds of the District’s stormwater system are in the municipal separate storm sewer system (MS4). In the MS4, stormwater is kept separate from sewage. However, stormwater runoff carries elevated pollutant loads, and the energy of the stormwater as it is discharged into streams and rivers can cause serious erosion of sensitive ecosystems.
In September 2009, DOEE issued a Request for Qualifications to design and install rainwater harvesting systems with advanced harvesting controllers at two District firehouses. The Project design was completed in August 2010 and construction was completed March 2012. The sites were designed to accommodate long-term monitoring of water quality and quantity, allowing DOEE to evaluate the widespread applicability of these technologies and better inform future design standards.
The objectives of the Project are both regional and site-specific. Holistically, the goal is to demonstrate to local governments, land managers, and the public how innovative low impact development (LID) practices can be used to improve water quality and reduce potable water usage in urban environments. The goal of the Project, funded by the American Recovery and Reinvestment Act, was to demonstrate new technologies that have a high potential for improving the quality, reducing the quantity, and altering the timing of stormwater runoff in the District, while also providing significant water conservation benefits.
The two sites included in the Project are DCFD Engine Company 3, located in the CSS, and Engine Company 25, located in the MS4. The sites were designed to accommodate long-term monitoring of water quality and quantity, allowing DOEE to evaluate the widespread applicability of these technologies and better inform future design standards.
Engine 3 collects runoff from 4,000 sq. ft. of roof area, and Engine 25 from 1,800 sq. ft. of parking area and 1,300 sq. ft. of roof area. Stormwater runoff from these areas is routed to the above-ground green cubes and stored for reuse by the firehouse staff for refilling the engine's onboard tank, vehicle cleaning, and surface wash down.