With new technique, engineers prepare Pacific Northwest dams for climate change

Engineers have devised a new management system to help dams in the Pacific Northwest be more efficient in a warmer climate.
Written by Andrew Nusca, Contributor

Engineers have devised a new management system to help dams in the Pacific Northwest be more efficient in a warmer climate.

Civil engineers at the University of Washington partnered with the U.S. Army Corps of Engineers to examine how they can better prepare dams in the Columbia River basin, the nation's largest hydropower system, for climate change.

Using a new technique to determine when to empty reservoirs in the winter (for flood control) and when to refill them in the spring (for torage for the coming year), the engineers believe they can reduce summer losses of hydropower from climate change by about a quarter.

Better still, fish flows would be improved and flooding risk would be reduced because reservoirs would fill more reliably, they said.

"There are anticipated dramatic changes in the snowpack which ultimately will affect when the water comes into the Columbia's reservoirs," said UW civil and environmental engineering professor Alan Hamlet, who co-authored the team's paper with researcher Se-Yeun Lee.

"Changes in flood control operations constitute only one climate-change adaptation strategy, but our study shows that incorporating climate change in flood management plans can improve the performance of existing water systems in future climates."

Hydrologic changes for the Pacific Northwest and other mountain regions have been predicted, resulting in less springtime snowpack, earlier snow melt, earlier peaks in river flow and lower summer flows.

Currently, water managers use a system based on historical stream-flow records to gauge when to open and close the floodgates. (Water managers are legally required to balance the needs of hydropower generation, irrigation, flood risk and regional needs.)

To improve that, engineers created a computer program that uses long-term forecasts, rather than historical records, to recalculate when to begin filling and emptying the major storage reservoirs in a scenario where temperatures are 2 degrees Celsius higher on average than today.

That temperature change has been predicted to occur in the Pacific Northwest by the second half of this century.

The result? Simulations show that water managers could successfully mitigate the effects of warmer conditions by refilling the system's reservoirs up to one month earlier in the spring.

"In talking to water resource managers, they often feel stymied because currently there are no established analytical procedures that can be used to rebalance their system for a different climate," Hamlet said in a statement. "They see the problem, but the tools to deal with the problem are not in place."

Their findings are published in the Journal of Water Resources Planning and Management.

This post was originally published on Smartplanet.com

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