Scientists to study effects of climate warming on Truckee River
Jeff DeLong
RGJ
01/14/2012
Scientists are beginning new research into how a warming climate could affect water supplies and flooding along the Truckee River, the waterway that serves as one of the region's central natural features and the source of most of its water.
The $1.7 million study by the U.S. Bureau of Reclamation is part of a larger effort examining eight rivers across the West, with California's Sacramento and San Joaquin rivers among them.
The goal is to get an early idea of what costly changes might be associated with climate change when it comes to the vital issue of water supplies and flooding along major river basins in the western United States, officials said.
"The goal is to look into the future so we can be prepared for it," said Mary Johannis, deputy planning officer for the Bureau of Reclamation in Sacramento.
Authorized by Congress in 2009 under the Secure Water Act, the study would build on information collected through a risk assessment released last year that examined potential impacts from climate change.
Experts have projected that in California's Sierra Nevada range, the climate could warm between 1 and 5 degrees between now and 2050, said Arlan Nickel, project manager for the Bureau of Reclamation.
One expected result could be "fairly significant" reductions in the amount of precipitation falling in upper-level watersheds as well as a change in how that precipitation falls, Nickel said.
"Not only will there potentially be less overall precipitation, but the type of precipitation will be different. There will be less snowfall and more rainfall," Nickel said.
Other studies suggest changes already are occurring, with the April 1 snowpack already 20 percent less on average than it was in the 1950s and 1960s, scientists with the Scripps Institution of Oceanography reported.
The new Bureau of Reclamation studies will attempt to further gauge coming changes in the Truckee Basin and elsewhere, potentially recommending different strategies in how reservoirs are managed and how water supplies are conserved, Johannis said. The study is expected to be completed in 2014.
"It's not just the supply end that may be changing with rising temperatures but the demand end," Johannis said.
John Erwin, a top water planner with the Truckee Meadows Water Authority, said he's hopeful the federal study will provide firmer guidance concerning how the primary water provider for Reno-Sparks should respond to the issue of climate change. Studies conducted thus far have been inconclusive on the issue, Erwin said.
"It will hopefully identify if there is a trend and what it means," Erwin said.
As a local partner in the study, TMWA is providing federal researchers with water demand and availability forecasts and population projections already prepared for regional water management plans, Erwin said.
Possible problems associated with climate change could not only mean shortages of water supplies but also too much water at once. Earlier snowmelt could flush more water downstream earlier in the season while more warm, "Pineapple Express"-type storms could also send raging torrents down the Truckee, Sacramento and other rivers.
"It's a condition that can create a tremendous amount of runoff in a short amount of time," Nickel said. "While there may be less precipitation, it may create these super storms that cause major flooding."
The danger of worsening flooding associated with climate change appears to be a real one, said Jay Alden, executive director of the Truckee River Flood Management Authority. The authority is another local partner, with studies it has conducted into river characteristics being incorporated into the federal research, Aldean said.
"We don't know what the impact is, but we know there is going to be one," Aldean said. "The frequency (of flooding) is expected to increase, and the magnitude is expected to increase."
