... I was pretty sure that LA water comes from the Eastern Sierra, and Vegas with a population about 1/20th of LA, from the Colorado River i.e. central Rockies. Salt Lake, which is about 1/50th the population of LA County, gets its water largely from the Wasatch. None of these sources are in the Great Basin.
The flow of the Colorado River is already oversubscribed. Any who use it and wish to grow are looking for alternate sources.
The eastern Sierra is in the Great Basin. The Sierra crest is part of the western border. Las Vegas has been trying recently to mine ground water from Spring and Snake valleys (in Nevada and Utah, surrounding Great Basin Nat'l Park) which are in the Great Basin. The west side of the Wasatch and Salt Lake (and the city) are in the Great Basin. The Wasatch crest is part of the eastern border.
But times do change. At the end of the last major glaciation in the western US, the Bonneville Basin (the Salt Lake area) sometimes drained into the Columbia River via the Snake River. And several times in the last 2000 years, the Colorado River has diverted itself into California's Coachella Valley and filled it to about sea level, or over 200 feet deep. While the filling was taking place, the upper Colorado basin was part of the Great Basin.
Dale B. Dalrymple
