The catastrophic drought that’s gripping the U.S. West is claiming a new victim: the hydropower dams that much of the region depends on for electricity supplies. Low water levels in key reservoirs mean that hydropower supplies are declining. One of the hardest hit areas is California, where output has tumbled to the lowest in more than five years. Nationally, the U.S. Energy Information Administration predicts electricity generation from conventional hydro sources will drop about 11% this year from 2020.