Salton Sea and Gran Desierto de Altar Near Gulf of California, USA and Mexico33.2N 115.7W
Visible as a navy blue area near the center of the left edge of this image of western USA and northwestern Mexico is the Salton Sea, a shallow, saline, endorheic rift lake located directly on the San Andreas Fault, predominantly in California’s Imperial Valley. The lake occupies the lowest elevations of the Salton Sink in the Colorado Desert of Imperial and Riverside counties in Southern California.
While it varies in dimensions and area with fluctuations in agricultural runoff and rainfall, the Salton Sea averages 15 mi (24 km) by 35 mi (56 km). With an average area of roughly 525 sq mi (1,360 km2), the Salton Sea is the largest lake in California. Average annual inflow is 1,360,000 acre·ft (1.68 km3), which is enough to maintain a maximum depth of 52 ft (16 m) and a total volume of about 7,500,000 acre·ft (9.3 km3).
An agricultural area can be seen south of the lake, near the edge of the Gran Desierto de Altar, one of the major portions of the Sonoran Desert of Mexico, including the only active erg dune region in North America. It extends across much of the northern border of the Gulf of California, reaching more than 100 kilometers east to west, and over 50 km north to south, and constitutes the largest continuous wilderness area within the Sonoran Desert.
The Gran Desierto covers approximately 5,700 km2, most of it in the Mexican state of Sonora. The northernmost edges overlap the border into southwestern Arizona. The dominant sand sheets and dunes range in thickness from less than one meter to greater than 120 meters. The total volume of sand in the Gran Desierto is about 60 km3. Most of that volume was delivered by the Pleistocene Colorado River which flowed through the present-day Gran Desierto area. The present-day Colorado River can be seen emptying sediments into the northern part of the Sea of Cortez (Gulf of California).