A law professor explains California's 'arcane' water rights system

In this photo taken Monday, May 18, 2015, a tractor tills the dry land on the acreage farmed by Gino Celli, near Stockton, Calif. Celli, who farms 1,500 acres of land and manages another 7,000 acres, has senior water rights and draws irrigation water from the Sacramento-San Joaquin River Delta. Farmers in the Sacramento-San Joaquin River Delta who have California's oldest water rights are proposing to voluntarily cut their use by 25 percent to avoid the possibility of even harsher restrictions by the state later this summer as the record drought continues. (AP Photo/Rich Pedroncelli)

Last month, California's water resources control board sent notices to senior water rights holders, ordering them to stop drawing water from rivers and streams.

Last month, California's water resources control board sent notices to so-called "senior water rights holders" ordering them to stop drawing water from rivers and streams.

While that might not sound surprising four years into a drought, to the growers, irrigation districts and communities that have held the rights to that water for more than a century, it's a very big deal.

Some are continuing to pump water, and others have filed lawsuits that challenge the restrictions—welcome to the arcane world of water rights in the West.

Stanford law professor Buzz Thompson, Director of the Woods Institute for the Environment, joined Take Two to explain why California's water rights system built up the way it did and how it's impacting the state's response to the drought.

To hear the full interview, click the link above.