The Los Angeles watershed already extends 1,500 miles eastward, to the eastern front of the Rocky Mountains.
If you look at a population map of the Western US --- generally west of the 100th parallel --- what you're looking at is a political power map represented as the function of urban areas to secure water rights within an otherwise arid landscape.
Denver and the Front Range, Omaha, Salt Lake, Phoenix, Las Vegas, and the California cities along the coast (Los Angeles, San Diego, San Francisco) and central valley (Stockton-Sacramento, Bakersfield, Fresno-Clovis-Visalia, Redding).
Oregon and Washington with the Wilamette and Columbia rivers are the exception.
If you look at a population map of the Western US --- generally west of the 100th parallel --- what you're looking at is a political power map represented as the function of urban areas to secure water rights within an otherwise arid landscape.
Cf: Earthlights <https://upload.wikimedia.org/wikipedia/en/thumb/4/48/Earthli...>
Denver and the Front Range, Omaha, Salt Lake, Phoenix, Las Vegas, and the California cities along the coast (Los Angeles, San Diego, San Francisco) and central valley (Stockton-Sacramento, Bakersfield, Fresno-Clovis-Visalia, Redding).
Oregon and Washington with the Wilamette and Columbia rivers are the exception.