NASA images show effects of drought on California’s largest reservoirs

Satellite images recently released by NASA show how drought has affected Northern California’s Shasta Lake and Lake Oroville, the largest reservoirs in the state.

NASA compared images taken earlier in June with images taken in the summer of 2019 to illustrate how water levels have declined over the two-year period.

The recent images show a tan strip outlining the perimeter of the two reservoirs. Sometimes called a “bathtub ring,” the phenomenon occurs when low water levels leave areas of the lake bed exposed, according to NASA. Two years ago, these regions of the reservoirs were completely submerged.

Lake Oroville’s water levels are at 35% of capacity as of June 16, according to NASA.

The Butte County reservoir’s low water levels also affect the state’s hydroelectric power plants, the Associated Press recently reported. State officials plan to shut down a major power plant for the second time in its history if the reservoir’s water levels fall below 640 feet.

Shasta Lake, located in Shasta County, is a major water source for the Central Valley. According to NASA, the reservoir is only at about 41% of its capacity as of June 16.

California hasn’t had such dry conditions since 1976 and 1977, according to NASA. Precipitation statewide ranges from 35% to 50% of normal, and little snowmelt from the Sierra Nevada has worsened conditions.

Dry conditions and hot temperatures also have sped up the pace of the drought, Jay Lund, co-director of the Center for Watershed Sciences at the UC Davis, told NASA. The second year of this drought is similar to the third or fourth year of the drought that occurred from 2012 to 2016.

“So California is having to react faster than usual,” he said. “On the other hand, the recent 2012-2016 drought has more of the institutions and plumbing already tuned-up for managing drought. In some ways we are better prepared. But it is like a hurricane on the East Coast: you can be prepared, but it is still a hurricane, and there will be damage.”