LOS ANGELES (Reuters) - California water regulators on Friday said they had approved a plan by some of the state's most senior water rights holders to voluntarily cut back water use by 25 percent in exchange for assurances that they would not face further cuts during the growing season.

So-called riparian growers in the Sacramento-San Joaquin River Delta who participate in the program have agreed to either reduce water diversions by 25 percent or fallow one-quarter of their land, the State Water Resources Control Board said.

"This proposal helps Delta growers manage the risk of potentially deeper curtailment, while ensuring significant water conservation efforts in this fourth year of drought,” State Water Board Chair Felicia Marcus said.

California is entering its fourth year of a devastating drought that has prompted Governor Jerry Brown to impose the state's first-ever mandatory cutbacks in urban water use, up to 36 percent in some communities.


(Reporting by Dan Whitcomb; Editing by Sandra Maler)