Lake Manly was a large freshwater lake which filled the Death Valley basin prior to the dry climatic period which has prevailed since the last ice age. Lake Manly receded due to increased evaporation, and to isolation from the Colorado River system, to which it was once connected.
As Lake Manly evaporated to the surface of Death Valley, it left a remarkable legacy. Under the surface of Death Valley is one of the world's largest underground reservoirs (aquifers). Being fed by the Amargosa River and Salt Creek, this aquifer is barely visible above ground at Badwater, California. Badwater, the lowest point in the valley (282 feet below sea level), is just low enough to reveal groundwater.
