Civil engineers at the University of Washington and the US Army Corps of Engineers' Seattle office investigated how dams in the basin, the US’ largest hydro power system, could be managed for a different climate.
Predicted future hydrologic changes for the Pacific Northwest, and other mountain regions, include less springtime snowpack, earlier snow melt, earlier peaks in river flow and lower summer flows. Water managers in the region currently use a system based on historical stream-flow records to gauge when to open and close the floodgates as part of a legally binding system that seeks to balance hydro power generation, flood risks, irrigation and other needs between regions.
The authors of the study 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 the Columbia River basin in a warmer climate. They compared historical conditions with a scenario where temperatures are 2 degrees Celsius higher on average than today, a change expected in the Pacific Northwest by the second half of this century.
The simulations suggested water managers could successfully deal with warmer conditions by refilling the system's reservoirs as much as one month earlier in the spring. The results suggested that power losses in the summer could be reduced by about a quarter, with flows for fish bolstered by filling reservoirs more reliably. It would also have positive benefits for flood management.
"Changes in flood control operations constitute only one climate-change adaptation strategy," said Alan Hamlet, a UW research assistant professor of civil and environmental engineering, "but our study shows that incorporating climate change in flood management plans can improve the performance of existing water systems in future climates."
For further information on the project, please visit www.washington.edu.
