The Delta is where the Sacramento and San Joaquin rivers meet, east of San Francisco Bay. It is the hub of California’s water supply and conveyance system.
In an average year, pumps withdraw about 5 million acre-feet from the estuary. That’s about one-fourth of all the water that flows into the Delta. A pair of canals transport it to semi-arid regions, including San Joaquin Valley farmland and Southern California cities.
This use, combined with other factors like invasive species and water pollution, has strained the Delta’s ecosystem.
It’s not just fish that are in trouble. The levees are old and at risk of breaking, especially as sea level rises. A major levee breach could allow seawater to flood pumping stations, spelling disaster for farmers and millions of people.
Adding to the pressures is a recent pact to use less water from the Colorado River, which is divided among seven states. These battles are intensifying as demand increases and supplies shrink. This could force Southern California to look for more water from other sources, like the Delta.