Lake Manly was a pluvial lake in Death Valley, California. It forms occasionally in Badwater Basin after heavy rainfall, but at its maximum extent during the so-called "Blackwelder stand," ending approximately 120,000 years before present, the lake covered much of Death Valley with a surface area of 1,600 square kilometers (620 sq mi). Water levels varied through its history, and the chronology is further complicated by active tectonic processes that have modified the elevations of the various shorelines of Lake Manly; during the Blackwelder stage they reached 47–90 meters (154–295 ft) above sea level. The lake received water mainly from the Amargosa River and at various points from the Mojave River and Owens River. The lake and its substantial catchment favored the spread of a number of aquatic species, including some lizards, pupfish and springsnails. The lake probably supported a substantial ecosystem, and a number of diatoms developed there.
In Death Valley, lakes existed during different times in the geological past. After some poorly defined lake stages during the Miocene, Pliocene and early Pleistocene, the first large lake stage occurred about 185,000–128,000 years ago during the Tahoe glacial stage and formed the Blackwelder shorelines. This lake was the largest known extent of Lake Manly; theories that the lake merged with Lake Mojave farther south or even overflowed into the Colorado River close to Ludlow and across several other basins are, however, questionable. After the drying of this lake a later lake stage occurred 35,000–10,000 years ago during the Tioga/Wisconsin glaciation; this lake was smaller than the Blackwelder lake. During the Holocene, the lake disappeared; today only ephemeral lakes occur in Death Valley during strong floods.
