This project constructed a $1.2 million underground storage facility at Mary Waters Park that holds 720,000 gallons of stormwater, nearly three times the size of the 270,000-gallon treatment system the City installed at Joe Taylor Park in 2010. The stormwater treatment efforts are part of the Green Grand Rapids initiative that includes preventing contaminated runoff from entering the Grand River.
Rainfall that lands on rooftops, lawns, and pavement picks up whatever debris and pollutants may reside there and runs off into creeks, streams, rivers and lakes. Unlike the city’s sanitary sewer system through which sewage travels to the city’s wastewater treatment plant, the storm sewer system drains an estimated 2 billion gallons of untreated surface water runoff annually into the Grand River.
The Mary Waters Park project routes stormwater runoff from surrounding residential and commercial properties to an underground holding facility. Prior to entering the infiltration area, large debris, such as bottles, cans, cigarette butts and other floatable pollutants that would otherwise flow into the Grand River, are removed with a hydrodynamic separator. Hydrodynamic separators are flow-through structures with a setting or separation unit to remove sediments and other pollutants. No outside power source is required because the energy of the flowing water allows the sediments to efficiently separate. The stormwater then infiltrates the sandy soil below. The system's design life is expected to exceed 50 years and eliminate more than 11 million gallons of untreated stormwater annually, based on an estimated annual average of 32 inches of rainfall, from entering the Grand River.
For more information, please read the press release from the project's groundbreaking ceremony.