Modeling by the Department of Water Resources for the 2022 Central Valley Flood Protection Plan Update shows that peak flood flows on the San Joaquin River could more than double with climate change, and peak flows on the Sacramento could increase by 40%.
In 2018, Daniel Swain, Baird Langenbrunner, and David Neelin found that there is a 50-50 chance of a flood on the level of the Great Flood of 1862 over the next 40 years (between 2020 and 2060.) Given recent extreme flood events in Yellowstone, British Columbia, Europe, and around the world, this is a disaster waiting to happen.
The California Senate introduced a bold Climate Budget Plan in May which includes $1 billion for flood protection and dam safety. In contrast, the Governor’s May Revise budget had no major new funding for flood management. Without these investments, California’s Central Valley and the Delta will be at increased risk from catastrophic flooding due to climate change.
Due to the historic $97 billion budget surplus, the budget passed by the legislature had $21 billion yet to be allocated across categories for the Climate and Energy package. From the legislative briefing for the budget bill, SB 154:
According to the League of California Cities.
American Geophysical Union. 2020. Extreme rainfall projected to get more severe, frequent with warming. Climate and population changes would expose millions more to severe flooding in continental U.S. Press Release. Nov 10, 2020.
California Department of Water Resources. Central Valley Flood Protection Plan web page. Accessed June 20, 2022.
Des Jardins, D. 2021. We need to plan for unprecedented flooding in California. California Water Research Blog. November 22, 2021.
Des Jardins, D. 2017. Urban Delta – 235,000 people at risk from levee failure in Stockton area. California Water Research Blog. November 27, 2017.
Swain, D.L., 2018. Increasing precipitation whiplash in twenty-first century California. Weather West research summary. April 22, 2018.
Swain, D.L., Langenbrunner, B., Neelin, J.D. et. al. 2018. Increasing precipitation volatility in twenty-first-century California. Nature Clim Change 8, 427–433. https://doi.org/10.1038/s41558-018-0140-y
Wikipedia. Great Flood of 1862. web page. Accessed June 20, 2022.