Urban Stormwater Runoff Research: Innovating Practice to Improve Water Quality

Friday, Oct. 15th, 3pm

375 Borlaug Hall

Andy Erickson, Ph.D., P.E.
St. Anthony Falls Laboratory


Urban stormwater runoff impacts water quality in lakes, river, and streams, causing eutrophication, bioaccumulation, and toxicity in aquatic ecosystems. To combat these impacts, recent research has developed innovations in stormwater treatment practices to reduce the amount pollution that reaches our valuable surface and ground-water resources. This seminar will describe three of these innovations: permeable pavement to reduce road salt application, iron enhanced sand filtration, and optimized biofiltration media selection. Permeable Pavement: Road salt (sodium chloride) is used for de-icing roadways during winter months in cold climates, but can have a negative impact on the environment. This research compared the impermeable pavements that are typically salted to permeable pavements which are not salted by measuring the friction, the surface temperature, and in-pavement temperature. Iron Enhanced Sand Filtration: Iron enhanced sand filtration (IESF) is an advanced stormwater treatment practice designed to capture particulate pollutants by filtration and soluble phosphorus (phosphate) by sorption to iron oxide. Results from small scale laboratory tests and full-scale installations in urban and agricultural watersheds subject to natural rainfall and runoff events will be explored. These studies represent different applications, in different watersheds, over different segments of the lifespan of IESFs. This presentation will summarize these studies and include an analysis of IESF performance with respect to the age of the practice, influent conditions, and filter size relative to the annual inflow volume. Biofiltration: Biofiltration has become common in urban landscapes because it is one of the most robust stormwater treatment practices available to designers. The most commonly used and recommended biofiltration media mixes, however, have been shown to export phosphate, contributing to water quality impairments. The objectives of this research are to identify which local and sustainable biofiltration media are effective for filtration rate, supporting plant growth and microbial function, and that do not release phosphate.