Prehistoric Lake Cahuilla (also known as Lake LeConte and Blake Sea) was an extensive freshwater lake that filled the Coachella, Imperial, and Mexicali valleys of southeastern California and northeastern Baja California during the centuries prior to Spanish entry into the region. The Salton Sea (about 55 kilometers long, 25 kilometers wide, and at an elevation of 65 meters below sea level), which was accidentally created in 1905, is a much smaller analog of its prehistoric predecessor, Lake Cahuilla (about 180 kilometers long, 50 kilometers wide, and rising to 12 meters above sea level, drowning the present sites of the cities of Mexicali, El Centro, and Indio).

Lake Cahuilla was created when the lower Colorado River shifted its course within its delta. Instead of flowing directly south to the head of the Gulf of California, the river's waters were diverted northwest into the Salton Basin, the base of which lay about 80 meters below sea level. Under climatic conditions similar to those of the early twentieth century, it would have taken about two decades of uninterrupted river flow to fill the basin to 12 meters above sea level (D. Weide 1976; Wilke 1978; Waters 1983; Laylander 1997). At that point, the lake would have overflowed to the south, feeding half of its waters through the Rio Hardy to the Gulf but losing the other half through evaporation. When the river shifted its course back to the south, the isolated basin would have taken more than five decades to completely dry out again.

To learn more, here are some interesting info about the lake Cahuilla:

The Lake Cahuilla is also referred to as the Blake Sea and the Lake LeConte.
Lake Cahuilla remains as one of the main area of resources for native people living within the area. In here, you can gather freshwater fish such as bonytails, as well as freshwater mussels.
The entire Lake Cahuilla area is also filled with marsh plants such as the reed, cattail, and tule among many others.
At around 500 AD, the Cahuilla Lake was actually ten times bigger than its present size. It fact, it was said to cover 3,900 square miles.
Visitors and tourists can camp around this beautiful lake. There are numerous campgrounds where you can spend the night.