The Russian River basin experiences some of the most variable climate in the U.S., with atmospheric rivers and their extreme precipitation driving this variability. These storms provide 25-50 percent of annual precipitation in key parts of the West, which can replenish water supply, but can also lead to hazardous and costly flooding, with atmospheric rivers causing 84 percent of Western U.S. flood damages, and 99 percent of damages in Sonoma County. The science of forecasting atmospheric rivers has continued to advance, particularly in understanding the origin and evolution of these storms, through enhanced observations before they make landfall, and through better modeling and prediction. “The skill of forecasting atmospheric rivers and their associated extreme precipitation and runoff, based on scientific advances and modern technology, have been shown by this program to enable Lake Mendocino to be operated more flexibly than in the past,” said Scripps research meteorologist F. Martin Ralph, director of CW3E. “Even in the third driest year on record, this program demonstrated the ability to apply science to save water, which is essential for California given how common droughts are in the region.”

To address these challenges, FIRO leverages current and improved forecasts of atmospheric rivers and their associated heavy precipitation and streamflow, through tools developed as part of the project. These data and tools inform reservoir operations, allowing more proactive and adaptive adjustments to variable weather conditions in decisions to retain or release water. FIRO does not require reservoir operators to employ information provided by FIRO; it merely provides additional information to inform operational decisions. The program represents an innovative use of science, technology, and observations for operators to adapt to variable conditions without costly reservoir infrastructure improvements. “The Lake Mendocino FIRO project is an example of how multiple agencies can collaborate to collectively explore the potential of emerging technologies in observations and forecasts and create an adaptive strategy with multiple benefits for water management in a changing climate,” said Michael Anderson, state climatologist with the California Department of Water Resources.

“Sonoma Water’s interest in innovation, and our partnership with federal and state agencies including the U.S. Army Corps of Engineers and the Center for Western Weather and Water Extremes, generated a breakthrough in water management for Sonoma Water,” said Lynda Hopkins, chair of the Sonoma Water Board of Directors and Sonoma County Board of Supervisors. “This comprehensive report demonstrates significant regional benefits for people, the environment, and the economy.”