The Omaha Sewer Maintenance Facility houses three green infrastructure practices on site, including a bioswale, a bioretention garden, and a small parking stall area with permeable pavement. This site is unique in that all three of the green infrastructure practices are interconnected with both the bioswale and the permeable pavement area draining into the bioretention garden. Altogether the three green infrastructure practices collect stormwater runoff from a 0.95-acre drainage area and are capable of holding roughly 2,250 cubic feet (16,831 gallons) of stormwater runoff.
A large focus of this project includes studying components of water balance within the bioretention garden in order to evaluate its performance. Several variables are being measured including precipitation, surface inflow and outflow of the system, evapotranspiration, and volume storage of the system during rain events. Soil moisture probes have been installed at various depths and locations throughout the garden in order to measure spatial characteristics of soil moisture pre- and post-rain events.
The Sewer Maintenance Facility demonstration project involves multi-agency collaboration between the Environmental Protection Agency (EPA) Office of Research and Development, the United States Geological Survey (USGS), the University of Nebraska, and the City of Omaha CSO and Stormwater programs.