Water securityNew Tool Could Guide Floodwater Management and Combat Ongoing Drought
Using a new computer framework, scientists are able to project future floodwaters under a changing climate. The approach could help California water managers plan for and redirect floodwaters toward groundwater aquifers, alleviating both flood and drought risks.
Floodwaters are not what most people consider a blessing. But they could help remedy California’s increasingly parched groundwater systems, according to a new Stanford-led study. The research, published in Science Advances, develops a framework to calculate future floodwater volumes under a changing climate and identifies areas where investments in California’s aging water infrastructure could amplify groundwater recharge. As the state grapples with more intense storms and droughts, stowing away floodwaters would not only reduce flood risks but also build more water reserves for drier times.
“This is the first comprehensive assessment of floodwater recharge potential in California under climate change,” said study lead author Xiaogang He, an assistant professor in civil and environmental engineering at the National University of Singapore who pursued the research as a postdoctoral fellow at Stanford’s Program on Water in the West.
Whether it’s rivers overflowing in the Central Valley flatlands, high-tide storms hitting lowland coastal areas, flash floods drenching southern deserts or impermeable concrete-laden cities pooling with water, California is susceptible to flooding. Alternately, looming droughts often raise concern about water supply, as diminished groundwater sinks land, contaminates drinking water and reduces surface supplies. These declining reserves also hamper climate resilience – during periods of drought up to 60 percent of the state’s water comes from groundwater and 85 percent of Californians depend on the resource for at least a portion of their water supply.
Water Banking
As climate change intensifies the severity and frequency of these extreme events, amplifying refill rates could help the state reach a more balanced groundwater budget. One practice, called water banking or managed aquifer recharge, involves augmenting surface infrastructure, such as reservoirs or pipelines, with underground infrastructure, such as aquifers and wells, to increase the transfer of floodwater for storage in groundwater basins.
A newer strategy for managing surface water, compared to more traditional methods like reservoirs and dams, water banking poses multiple benefits including flood risk reduction and improved ecosystem services. While groundwater basins offer a vast network for water safekeeping, pinpointing areas prime for replenishment, gauging infrastructure needed and the amount of water available remains key, especially in a warming and uncertain climate.
