In 1900, the California Development Company began construction of irrigation canals to divert water from the Colorado River into the Salton Sink, a dry lake bed. After construction of these irrigation canals, the Salton Sink became fertile for a time, allowing farmers to plant crops.
Within two years, the Imperial Canal became filled with silt from the Colorado River. Engineers tried to alleviate the blockages to no avail. In 1905, heavy rainfall and snowmelt caused the Colorado River to swell, overrunning a set of headgates for the Alamo Canal. The resulting flood poured down the canal, breached an Imperial Valley dike, and ran down two former dry arroyos: the New River in the west, and the Alamo River in the east. Over about two years, these two newly created rivers sporadically carried the entire volume of the Colorado River into the Salton Sink.
The Southern Pacific Railroad tried to stop the flooding by dumping earth into the canal's headgates area, but the effort was not fast enough, and the river eroded deeper and deeper into the dry desert sand of the Imperial Valley. A large waterfall formed as a result and began cutting rapidly upstream along the path of the Alamo Canal that now was occupied by the Colorado. This waterfall was initially 15 feet high, but grew to 80 feet high before the flow through the breach was stopped. Originally, it was feared that the waterfall would recede upstream to the true main path of the Colorado, becoming up to 100 to 300 high, at which point it would be practically impossible to fix the problem.
As the basin filled, the town of Salton, a Southern Pacific Railroad siding, and Torres-Martinez Native American land were submerged. The sudden influx of water and the lack of any drainage from the basin resulted in the formation of the Salton Sea.
https://www.raremaps.com/gallery/detail/58339/reconnaissance-map-of-the-salton-sink-california-1906-us-geological-survey
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