Water scarcity and endangered species troubles will keep growing unless politicians make "hard decisions" about priorities for water use in the California Bay delta, according to a new report out today by the National Research Council (NRC). Blue-ribbon panels, working groups, and stakeholder meetings have tried to come together to make such choices for decades. But because there are so many entrenched competing interests among farmers, fishers, and urban populations that depend on the water, to date there has been no consensus about the best path forward.
The runoff from California's northern Sierra flows into the Sacramento and San Joaquin rivers and their tributaries, through the delta, and eventually out San Francisco Bay. Some 25 million people throughout California depend on delta water. Pumping stations divert massive quantities to farmers in the Central Valley as well as cities in southern California. But these water removals are increasing the stress—along with dams, declining river habitat, and pollution—on regional fish populations, including several species of salmon and a fingerling called the delta smelt. These troubles will likely be exacerbated by climate change if it shifts spring runoffs earlier in the year and raises water temperatures in the summer months, the NRC panel concludes.