Drought is endemic to India, an endless cycle of water shortages followed by replenishing monsoon rains. Ashok Mishra experienced it firsthand growing up in rural India.
He also lived close to the Hirakud Dam, built across the Mahanadi River and India’s largest dam.
“As a child, I was fascinated by how this reservoir stored and managed water during droughts and floods,” says Mishra, Dean’s Professor of Civil Engineering. “This is a vitally important and complex task, as we see drought and flood in the same year on the Indian subcontinent.”
That childhood curiosity has led to a lifelong focus on water security, especially during extreme climate events such as drought.
“Drought is often considered the most complex and least understood of natural environmental hazards, with an immediate and serious threat to water security, food, energy and infrastructure that impacts the lives of millions,” he says. “Persistent droughts can force foundational changes in how communities use the land; for example, water-intensive industries potentially relocating, and agricultural production shifting to other regions.”
Mishra received a National Science Foundation CAREER Award in 2017 to create a model for improving water sustainability during extreme droughts. He’ll test his methodology in the Savannah River Basin in South Carolina and Georgia, then scale it nationally.
According to Mishra, there is currently no single physical variable available to quantify droughts. As a result, it’s hard to pinpoint when a drought starts and ends, as well as to determine its magnitude and spatial extent. There is also a need to quantify water security threats by sector and region. “This is imperative given the looming threat of drought caused by climate change,” he says, “which will impact 80 percent of the global population. Already, 35-40 percent of the area of the United States has been affected by severe droughts in recent years.”
Mishra is taking a data science approach. He’s built his own “reservoir” of big data that includes high-resolution geographic information systems; weather data from the National Oceanic and Atmospheric Administration; streamflow data from the United States Geological Survey; agricultural water-use figures; a digital elevation model; cropland data from the U.S. Department of Agriculture; soil data from the States Soil Geographic Database; and climate change scenarios from the Coupled Model Intercomparison Project 5, a protocol for studying the output of coupled atmosphere–ocean general circulation models used by the international climate modeling community.
These data sources vary in their spatial and temporal resolutions (the number of pixels in each digital image, and how often the data is collected), so he’ll use techniques like interpolation, aggregation and disaggregation to “cleanse” the data and standardize the numbers: “I will employ statistical modeling to quantify the interdependence and cascading effects between drought indicators, create a decision-making framework to improve water security, and establish a drought early-warning system.”
He also uses satellite remote sensing products to monitor soil moisture and drought indices. “Novel technologies like these can help policymakers utilize water resources optimally; farmers can use sensors to decide when and how much to irrigate, depending on crop requirements,” Mishra explains.
His overall goal is “to promote sustainable water resources management that can support human well-being, and that is also compatible with sustaining natural environmental systems.”
Mishra has been cited more than 5,500 times, according to Google Scholar; his most renowned paper, “A review of drought concepts,” has been referenced more than 2,000 times.
“The article revolutionized how drought is understood by the scientific, social and policy communities and filled major gaps in comprehending the linkage between the drought and vulnerability indicators associated with water security,” says Hong-Yi Li, an assistant professor from the Department of Civil and Environmental Engineering at the University of Houston. “It was always the first journal article I passed along to any of my students or postdocs who are interested in drought. I will keep doing so for at least another five to 10 years.”