Drought-stricken California on Thursday shut down one of its largest hydroelectric plants because there’s not enough water to power it.

The six-turbine Edward Hyatt Power Plant was taken off-line after the water level in the Oroville Dam reservoir that feeds it sank to an historic low of less than 642 feet (195.7 meters) above mean sea level.

The reservoir in the Sierra Nevada foothills north of Sacramento was less than a quarter full.