More recent droughts, in 1976–77, 1988––09, led to aggressive urban conservation programmes and greater use of water markets, such as the Emergency Drought Water Banks of the 1990s that facilitated the purchase, sale and transfer of water.
Other responses included increased groundwater extraction and use, water conservation, more-extensive irrigation and more infrastructure for conveyance, storage, wastewater re-use and brackish-water desalination.
Curtailments in surface-water pumping to protect endangered species limit supplies to the Central Valley for agriculture, increasing unemployment among farm workers.
Political conflict over urban, environment and agricultural water rights has erupted.
Pool networks become disconnected and food webs are broken.
The reductions in water diversions in 2012–13 to protect endangered species in the Sacramento–San Joaquin River Delta region have meant less water for urban and agricultural users.
Now the state is nearing its water limits and can no longer simply build its way out.
California's water troubles are a harbinger of things to come around the world, wherever population and industries are growing.
Most of these innovations have served to maintain or expand water supplies.
Today, the state has one of the world's most engineered and diversified water systems, including six aqueduct networks more than 2,000 kilometres long and in excess of 1,400 dams.