For the last century, California has had two key strategies for dealing with its winter wet season: Build big reservoirs on the rivers draining the Sierra Nevada to capture and store seasonal runoff and floodwater, and rely on mountain snowpack to build up in the winter and melt slowly over the spring and early summer.
One important approach is to improve ability to capture, treat and use urban storm water, especially in the Los Angeles and San Francisco Bay areas.
Every year, hundreds of billions of gallons of storm water wash into Santa Monica Bay, Long Beach Harbor and the San Francisco Bay. Even one inch of rain in Los Angeles can generate more than 10 billion gallons of runoff.
It's possible to capture quite a bit of that water after repaving streets and parking lots with porous materials so that rain can percolate into the ground and recharge aquifers. Parks, open spaces and urban watersheds must be reconfigured with the same goal in mind. And homeowners need incentives to capture rainfall too, for use on their gardens and landscapes.
Such strategies have benefits beyond increasing local water supplies. They can reduce urban flooding, restore the health of local waterways such as the Los Angeles River and reduce pollution flowing into the oceans and onto the beaches.