Massive storms over a few weeks have led to extreme flooding, yet California remains in an historic drought, which has prompted experts to explore ways to better manage floodwaters.
A recent article by NPR describes how water managers are testing an innovative approach with two local reservoirs to help increase the state’s water supply.
A state law in California requires reservoirs to release water in the fall and winter so they have capacity to catch the runoff from winter storms to prevent floods downstream.
Water managers for Folsom Reservoir and Lake Mendocino are using an innovative approach to guide their operations. They are only emptying these two reservoirs if significant precipitation is forecast.
Water managers walk a tightrope in California. “If a dam is overwhelmed, potentially hundreds of thousands of people risk being flooded downstream. Stay too empty, and cities and agriculture run short of water when a drought hits,” the article states.
Many of the rules used to govern California reservoirs were created before climate change contributed to the severe drought in most of the western United States.
“Back when the dams were built, it was a pretty wise choice in my opinion not to use weather forecasts because they weren’t very good,” Marty Ralph, director for the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography, said to NPR. “But now with satellites and radars and models and science, there’s been a lot of improvements, so it seems sensible to give it a try.”
The Bureau of Reclamation says it is tracking the effectiveness of the approach used with Folsom Reservoir and Lake Mendocino to see if it might work elsewhere.
“The climate is changing, hydrology is changing, weather patterns are changing,” David Raff, chief engineer at the Bureau of Reclamation, said to NPR. “In addition to that, the demand for water is increasing in the western United States. When you put those things together, there is a significant interest to optimize operations in all of our reservoirs.”
Photo from NPR.org and by Kenneth James/California Department of Water Resources