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Stormwater Irrigation Volume I: Evapotranspiration and Nitrate Reduction After Biofiltration to Reduce Health Risks

Martin Wanielista, University of Central Florida
Ewoud Hulstein, University of Central Florida

This research, performed by the University of Central Florida Stormwater Management Academy, used field experiments to determine the evapotranspiration and impacts on ground water of nitrogen of stormwater used to irrigate St Augustine lawns.

Abstract

Irrigation of detained stormwater is an option available for volume and pollution control. Volume control is accomplished when detained waters normally discharged from a detention facility are used instead for irrigation. However, a health risk may result if the nitrate in the irrigation water is not attenuated in the plant and soil matrix. The nitrate level in stormwater ponds is generally much less that the health risk specified as 10 mg/L in Drinking water standards. Nevertheless, the fate of nitrate in the soil plant matrix has not been documented. In addition, there are other potential problems associated with not maintaining a hydrologic balance. Lack of volume control could result in environmental problems, such as reduced springflow and eutrophication. In an effort to address these issues, a combination of best management practices for volume control can be adhered to in the process of a land use change. The practice of using excess detained stormwater as a source for irrigation will minimize some of the impacts associated with changes to the hydrologic and nitrogen cycles associated with urbanization.