Q: Where does Lake Tahoes water come from and how dependent is it on precipitation? Is it self-renewing from a very deep source of great size? Linda Johnson, Salt Lake City
A: Because of its great depth (1,645 feet), Lake Tahoe holds enough water to cover the entire state of California to a depth of about 14 inches, according to the U.S. Forest Service Lake Tahoe Basin Management Unit. But if that somehow were to happen, the lake would remain depleted for a very long time.
Lake Tahoes water is pretty much entirely dependent on precipitation. Although some groundwater may seep into the lake from the mountains that surround it, that groundwater is also largely present because of precipitation.
The watershed that feeds snowmelt into Lake Tahoe is large: about 500 square miles. Even so, it would take many years to refill the lake were it to go dry. The Forest Service estimates that completely refilling the lake from precipitation would take about 700 years.
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