UTSA studies sustainable retrofitting techniques for groundwater filtration systems

UTSA researcher Azza Kamal says study’s finding can help city and state officials / Above: Retrofitting campus sormwater management structures through Low Impact Development (LID); a proposed design by architecture and civil and environmental Engineering students”

(Aug. 30, 2016) —Azza Kamal, assistant professor of research, and graduate students with The University of Texas at San Antonio (UTSA) College of Architecture, Construction and Planning have conducted top-tier research to prevent San Antonio drinking water from becoming polluted after heavy rainfall. 

"Chemical pollutants tend to accumulate on hard surfaces like roofs, roads and parking lots,” Kamal said. "On dry days, this isn’t a huge problem, but, during heavy rainfall, these pollutant loads can be picked up by the rain water. The polluted water is then filtered down to groundwater reservoirs, like the Edwards Aquifer."

The Edwards Aquifer is the main source of drinking water for millions of people living in central Texas. According to Kamal, the increased urbanization around areas like the aquifer’s recharge zone increases the amount of pollutants that are filtered after each rainfall. 

With funding from the San Antonio River Authority, the Edwards Aquifer Authority and the Greater Edwards Aquifer Alliance, Kamal and her students developed a model that uses specialized geospatial technology and ranking systems to identify storm water filtration structures that are most heavily impacted by heavy pollutant loads. 

Storm water is currently filtered using sand filter basins, small ponds with a layer of sand at their base that collect runoff from hard surfaces. The basins’ sand layer acts as a natural filter for sediment and pollutants.

More than 3,000 of these structures exist in Bexar County, and several exist on the UTSA Main Campus, which rests on the Edwards Aquifer Recharge Zone.

“Our goal was to identify which areas in this region are more likely to be impacted negatively due to high levels of pollutants,” Kamal said. “We spent the past year studying the impact of urbanization on water contamination and how well the current storm water filtration systems currently are working."

They found that an estimated 15 percent of the filtration structures are not currently functioning at levels needed to efficiently clean the pollutants from the water.

Now that the research is finished, Kamal said local and state regulators can use the new model, called a Best Management Practices (BMP) Site Selection Model, to properly allocate resources to retrofit existing dysfunctional structures and add new sustainable filtration structures in high-polluted areas.

“Our model can provide a roadmap to enhance water quality, reduce storm water runoff and improve community’s health outcomes,” Kamal said. “It also offers flexibility for other cities and regions across the country to adapt it to their needs.”

In addition to developing the BMP Site Selection Model, Kamal and 13 architecture students earlier this year worked on another Edwards Aquifer-related design research. In collaboration with lead researchers Marcio Giacomoni, assistant professor of civil and environmental engineering, Heather Shipley, associate professor and chair of the UTSA Department of Civil and Environmental Engineering, and the UTSA Office of Facility Planning, they studied and re-designed storm water decontamination structures using rain gardens and other resilient techniques.  

- Jesus Chavez

Learn more about the UTSA College of Architecture, Construction and Planning.

Learn more about Giacomoni and Shipley’s research.

Learn more about the San Antonio River Authority, the Edwards Aquifer Authority and the Greater Edwards Aquifer Alliance.

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