Governor Brown has taken critically important action to potentially boost water supply and provide better flood protection in California. He signed Senate Bill 758, The Atmospheric Rivers Research, Mitigation and Climate Forecasting Act, and set aside funds in the current state budget to implement this bill.  His action will accelerate what may be the lowest cost, nearest term, and most likely to succeed effort to increase surface water supply and improve flood protection in our state.

In most cases the rules used to operate reservoirs in California are based on old technology that forces dam operators to unnecessarily release stored water during droughts and miss opportunities to improve public safety by releasing larger volumes before extreme rain events occur. The rules that drive these decisions were largely set when the dams were built, in this case decades ago, and are based on the weather forecasting technology available way back then. The program Governor Brown initiated will help determine if reservoir operations could be safely modified to store more of this water during droughts and release more of this water when necessary for flood protection.

Researchers at Scripps Institution of Oceanography, the U.S. Army Corps of Engineers, the National Oceanic and Atmospheric Administration and other labs are now demonstrating that through targeted advances in scientific knowledge, observations and weather models that the potential exists to allow these existing reservoirs to be re-operated (i.e., to introduce new reservoir operations procedures). During non-flood situations the goal is to keep more water in storage in winter for use in California homes, businesses and farms in summer, without increasing flood risk in the winter. During potential flood situations the effort would also enhance flood-risk mitigation capacity by releasing water before a major storm, but with confidence that the storm will at least replace that released water. In addition, snowpack in the future is likely to decrease so better understanding and managing extreme rainfall events due to ARs will become increasingly important.

An atmospheric river storm that came through last December delivered 18% of average annual precipitation in the Sacramento Basin in just one week. The same thing happened last March when a series of atmospheric rivers delivered 25% of our precipitation for the year. The Association of California Water Agencies is actively working to improve our understanding of atmospheric rivers and make California a leader in using technological advances to meet water needs here in our state. We have member agencies working closely with Scripps to demonstrate the impact of this work on water supply reliability at the local level. Dr. F. Martin Ralph from Scripps was the keynote speaker at our recent conference and clearly highlighted the role that atmospheric rivers play in both supplying water to California and in causing the major floods, and how better science and predictions of atmospheric rivers could support future water supply and flood control operations.

We can continue as we have for decades letting this potential increased water supply flow to the sea and taking on unnecessary flood risks or we can apply new weather technology together with sound science and engineering to hold more water in existing dams for our homes, farms and businesses and better protect our homes and families at the same time. Thankfully Governor Brown has taken steps to go forward on Atmospheric Rivers.

Steven E. LaMar

Chair, Association of California Water Agencies

Federal Affairs Committee

Photo Credit: Matthew Corley / shutterstock.com