Unpredictable flooding and droughts, which scientists predict will intensify with climate change, elevate the importance of dams for managing and storing water, even in places that normally receive adequate rainfall. So maintaining the world's existing dams can help assure farmers will have the water they need to feed the planet's burgeoning population.
Andrew Schreiber and Charles Chang
Now, Agricultural and Applied Economics graduate students Charles Chang
and Andrew Schreiber
have created software that can quickly and cheaply determine a dam's structural integrity, using their algorithm and data from easily installed fiber-optic sensors, such as those already in use at the Koksarai Dam in Kazakhstan.
"Our system gives water managers a more cost-effective way to monitor the overall integrity of dams than any other technology," says Chang. He is collaborating with a team of engineers who developed the sensors, led by Prof. Ki-Tae Chang at Korea's Kumoh National University of Technology.
The sensors, which measure water seepage through a dam, provide real-time data the researchers are using to locate areas of erosion that could eventually undermine the dam's capacity.
Koksarai Dam in Kazakhstan
"We are targeting dams in developing countries, most of which are used as reservoirs for agriculture. Many of them have no solid core and are easily moved by high water pressure, or they are older dams that need maintenance. We can give water managers the information they need to decide whether repairs are required -- that's the geoscience aspect of the research," Chang explains.
"I'm excited about the interdisciplinary team we have working on the project," he adds, which includes Prof. Michael Cardiff
, a UW hydrogeologist, and Jesse Holtzer, a computer science graduate student working with the Optimization Group at the Wisconsin Institute for Discovery
. Professors Tom Rutherford
and Corbett Grainger
are also advising the researchers. Chang and Schreiber are both in their second year of the AAE graduate program.
"Some models of dam sustainability measure the effects of sedimentation in the reservoir, but our project goes farther by looking at the erosion factor," says Chang. "For example, if Kazakhstan were to experience less rainfall due to climate change in the coming years, we would want to maintain a higher reservoir level in the dam for future agricultural use. But we also know that higher water levels can trigger more erosion."
As economists, Chang and Schreiber want to help developing country governments predict how much they will need to invest in a dam to allow it to increase its capacity. And because different climate change scenarios can affect both sedimentation and erosion – the main causes of dam failure – the economics team will model the returns to investment in dam maintenance or abandonment. "What is the benefit to society to have that dam reinforced or allowed to collapse?" Chang asks.
They also plan to monitor the water quality within the dam's reservoir, partnering with a startup venture project, SeaStat, that makes inexpensive water quality detection technology.
"Irrigation plans that don't take account of water quality can adversely affect agricultural production and the downstream ecosystem. For example, pumping from the reservoir can increase salinity. So an interesting question about water quality then becomes, how much irrigation is optimal?"says Chang.
While an undergraduate at Northwestern, Chang developed 3-D modeling software used by engineers to check the foundations of high rise buildings. "It's important for tall buildings not to collapse," he says, "but keeping dams sound can help save humanity from some of the effects of climate change."
by Barbara Forrest