The Salt and Seas in Southern California

The Coachella and Imperial valleys were a giant body of water until the Spanish era in Southern California. It continued to be a sort of seasonal lake until 1700, but because of the Colorado rivers whimsy, it no longer periodically flowed into the sea. After 1700, it was just a dry valley. The interesting thing about it is that over millions of years, the Colorado river deposited tremendous amounts of silt in the valley.