Ancient Lake Cahuilla High Water Mark

Lake Cahuilla was an ancient freshwater lake in the Salton Trough of southern California. It covered parts of the Coachella, Imperial and Mexicali valleys and was formed when the Colorado River overflowed its banks or was diverted northwest by its own sediments, which temporarily blocked the flow to the Gulf of California (Sea of Cortez). Although there have been a few smaller incarnations of the lake in historic time, the main high water mark is thought to have occurred sometime between 1,000 and 1,500 AD.