I just had an interesting visit to a very fascinating place that may not be around very much longer, the Salton Sea.
Most of this information comes from this website: http://saltonseamuseum.org. Please check it often for updated information.
Most lakes have been around for thousands of years and are a part of the natural balance of nature. The Salton Sea was made by accident. An engineering mistake flooded the waters of the Colorado River into the Imperial Valley over the course of almost two years. The valley was not new to water:
Above you can see how the area where the Salton Sea is now used to be a part of the Gulf of California. Over the centuries the Colorado River dumped enough sediment to cut the Imperial Valley off. Over the years 5 lakes have come and gone from the region.