In 1905, dikes along the Colorado River were breached by heavy rains, and water flooded into the Salton Sink, site of an ancient sea.  The entire flow of the river was periodically channeled into the valley until the construction of Hoover Dam enabled flood control.  The Salton Sea was stocked with game fish and became a popular recreation site for many years, but gradually became more and more salty due to lack of an outflow and high salinity runoff from surrounding agriculture.  Today, only tilapia can survive in the lake, which is nearly as salty as the Great Salt Lake, and it is ringed by dessicated fish carcasses and failed developments.