How's your river running?

Recent hydrologic-modeling advances have given climate scientists the ability to more accurately pinpoint the implications of climate change across specific regions. Tapash Das, David Pierce, Dan Cayan and Mike Dettinger of Scripps Institution of Oceanography at UC San Diego are exploiting these advances to explore the sensitivities of river water runoff to changes in temperature and precipitation across the Western United States.

In results discussed during the conference of the American Geophysical Union in December, they found that total streamflow decreases in major western U.S. rivers vary from as little as 1 percent per degree Celsius of climate warming to as much as 7 percent per degree Celsius. They say flow from California’s Sierra Nevada Rivers are not as sensitive to warming as the Colorado and Pacific Northwest river basins.

Warming conditions carry the greatest influence, they found, at locations with significant snow but that lie close to the freezing point.

“Our hope is to drill down and be able to inform city planners and water managers whether their region is likely to be more or less sensitive to climate change,” said Pierce. “This information could help them plan for future conditions.”

Das says new studies will factor in changes across the seasons with the goal of gauging sensitivities to warming in various months.

Mario Aguilera/Robert Monroe