While in orbit over the San Francisco Bay Area, an astronaut onboard the International Space Station (ISS) took this photograph of the south end of Lake Berryessa, a large freshwater reservoir in nearby Napa County, California. The canyons surrounding the lake provide areas for water recreation, marinas, and campgrounds. The lake is primarily fed by Putah Creek, with additional contributions from smaller waterways such as Capell Creek and Wragg Creek. The visible swirls in the middle of the lake are sediments stirred up by the flow of the water around the canyon walls.
The artificial lake was created in the 1950s with the construction of Monticello Dam and flooding of Berryessa Valley. The dam stands 304 feet (93 meters) tall and stretches about 1,300 feet (400 meters) across Devil’s Gate, a narrow pass on Putah Creek. Lake Berryessa stores and distributes water to surrounding cities and nearby farmlands, including vineyards in Napa Valley.
Water levels in Lake Berryessa and Putah Creek were low at the time of this July 2021 photo, when the entire state of California faced serious drought. The thin, light-colored zone along the shorelines is a “bathtub ring” of dry lakebed where water levels have dropped and vegetation-free sediments stand out.
During an extended drought in the 1980s, Putah Creek dried up downstream of the reservoir. To prevent this from occurring again, dam operators now regularly release water to mimic the previous seasonal ebb and flow in the creek. Lake Berryessa also provides flood protection for parts of Northern California during large rain events in the winter.
Astronaut photograph ISS065-E-165726 was acquired on July 4, 2021, with a Nikon D5 digital camera using a focal length of 1150 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 65 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Sara Schmidt, GeoControl Systems, JETS Contract at NASA-JSC.