New Waves November 2007

Breaking news about water resources research and education in Texas

TWRI grant recipient studies effects of urbanization on freshwater inflows

By Kari Miller

Texas A&M University international graduate student Debabrata Sahoo is working with his advising professor Dr. Patricia Smith from Texas A&M University's Department of Biological and Agricultural Engineering to study the effects of urbanization on estuarine environmental flows to the San Antonio Bay/Guadalupe Estuary system.

Sahoo, originally from India and a recipient of a $5,000 2006-07 Texas Water Resources Institute (TWRI) research grant, said estuaries are unique ecosystems that provide a habitat for many species.

"Estuaries are the connecting link between terrestrial and marine ecosystems and provide a critical coastal habitat that is essential both ecologically and economically," Sahoo said. "Important species depend on estuaries for their survival and contribute more than 90 percent of the total fisheries activity in the Gulf of Mexico."

According to his final report, the San Antonio River watershed is experiencing rapid urbanization. Changes in the watershed are likely altering the freshwater inflows to the San Antonio Bay/Guadalupe Estuary system.

Sahoo's research investigated this problem by modeling the effect of watershed development due to urbanization using remotely sensed data and a distributed hydrologic model. He also used a genetic algorithm to optimize the hydrologic parameters in the forecasting model. In the future, he wants to use genetic algorithms for allocation of land use to meet the freshwater demands of both the increasing population of San Antonio and the freshwater inflow requirements to maintain a healthy San Antonio Bay/Guadalupe Estuary ecosystem.

"My research focuses on application of remote sensing, evolutionary algorithms, time series and wavelets in conjunction with a hydrologic model to characterize freshwater inflows to the estuary," he said.

Sahoo said the results of his research suggest that urban growth has affected baseflow and storm flow. Model simulations suggested that an increase in impervious surfaces shifted the magnitude of peak flows.

"The results will help scientists, policy makers and water managers in the proper planning of water resources," he said. "Modeling the effect of urbanization on freshwater inflows and using a genetic algorithm to obtain the optimal solution for effective land allocation will aid in water resources management that meets both economic and ecological needs."

Sahoo said he would like to continue exploring water and environmental problems during his graduate studies.

His research was funded by TWRI through the U.S. Geological Survey as part of the National Institutes for Water Research annual research program. TWRI is the designated institute for water resources research in Texas. For more information on Sahoo's research, visit USGS Research Grants.

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