Global Courant
California’s two largest reservoirs are all but full after reaching dangerously low levels late last year.
Lake Shasta, 96% filled, and Lake Oroville, 100%, had fallen to about 25% to 30% of their capacity before the state’s historically wet winter rejuvenated them.
Statewide, reservoirs are at 85% of total capacity, well above their 30-year average of 73% for the month of June. With the Sierra Nevada snowpack still more than three times their normal level for mid-June, they are expected to fill even more as the snow melts.
The before-and-after images below from NASA show Lake Shasta on November 18, 2022, when the lake was only at 31% capacity, and again on May 29, 2023, when it was 98% full.
California’s largest reservoir hadn’t been this full in more than four years, he said California Department of Water Resources facts. A “bathtub ring” around the lake showing how far the waterline had fallen was clearly visible in November, but had disappeared by May.
Lake Oroville, in Butte County, has also undergone a spectacular transformation.
Since December 1, the water level of the lake has dropped climbed more than 240 feet thanks to more than 2.5 million acres of additional water caused by a series of powerful winter storms and the melting of a historically deep snowpack. That puts the reservoir at 127% of the historical average for the date, show state data.
The image below shows the lake at Enterprise Bridge on December 21, when the level was 29% of capacity. A narrow strip of water meanders through the bottom of the gully, well below the span of the bridge.
Lake Oroville under Enterprise Bridge was nearly gone on December 21, 2022.
(Ken James / California Department of Water Resources)
Less than half a year later, the landscape had undergone a noticeable shift. In the image below, taken on June 12, water levels are dramatically higher in the same part of Lake Oroville, almost to the top of the piles supporting the bridge.
A similar view of Lake Oroville on June 12, 2023 showed a dramatic transformation. The reservoir is now 100% full.
(Ken James / California Department of Water Resources)
In the second photo, the reservoir is at 100% capacity, flooding the barren hills previously exposed to low water levels.
A study of satellite data from NASA’s Jet Propulsion Laboratory found that winter yielded the largest net water gain in California’s lakes in the 22 years the metric had been tracked.
Between October 2022 and March 2023, the Central Valley’s “lakes, rivers, soil, snow and underground aquifers” saw their levels rise by the equivalent of 20 inches, or about twice the average gain over the past 22 years.
However, groundwater levels remain depleted, experts say, and may continue to do so in the future.
“One good winter of rain and snow can’t make up for years of extreme drought and extensive groundwater use,” said Felix Landerer, a scientist at JPL.
Times staff writer Nathan Solis contributed to this report.
