Roughly 95% of the Central Valley's historical floodplains have been cut off from its rivers by levees built in the early 1900s, and with them, salmon lost access to one of their most important food sources: the aquatic insects and zooplankton that floodplain wetlands naturally produce in huge quantities. Without that food web, juvenile salmon in leveed river channels grow more slowly and face longer, riskier migrations to the ocean.

CalTrout's answer, launched in 2017 with NOAA, the California Department of Fish and Wildlife, UC Davis's Center for Watershed Sciences, the California Rice Commission, Northern California water agencies, and a growing coalition of conservation and agricultural partners, is refreshingly simple: pay farmers, through a reverse auction, to flood their rice fields during winter months when the fields would otherwise sit fallow. The flooded fields function as surrogate wetlands, producing up to 15,000% more invertebrate biomass than a leveed river channel would, and when that water is released back into rivers like the Sacramento and the Feather, it carries that food supply straight to migrating fish. The results are striking: fish raised on these activated floodplains can grow up to 12 times faster than fish in the river channel alone.

After pilot seasons in 2019 and 2021, the program opened to public enrollment in Water Year 2023 and has scaled quickly since: participation grew from 8,775 acres in 2021 to 29,000 acres in 2023, 27,400 acres in 2024, and 25,100 acres in 2025, with the cost per acre-cycle actually falling each year, from $46.28 in 2023 to $35.36 in 2025, as the program has matured. The long-term vision is to manage 500,000 acre-cycles annually in perpetuity, though scaling to that level would require $4 to $6 million a year, well above the roughly $2 million the program has run on through 2025, and funding is not yet secured.