Friant Dam near Fresno CA provides water to 15,000 San Joaquin Valley farmers. It can’t store enough, especially during times of drought. Enter plans to build a much bigger dam, Temperance Flat, at the back of the lake. It would cost $3 billion. Enviros are opposed to it, citing huge damage to habitat as well as making it even harder to bring back the salmon.
Seventy years ago, salmon runs ended on the San Joaquin River because they built concrete channels and reversed the flow of the river. Lots of landowners lost their water and now the dry bed area gets filled with pesticide runoff and salts. Lawsuits forced the dam to start to provide water for salmon.
This is an instructive microcosm of the California water wars. The California Spigot has an in-depth article which I highly recommend.