There are considerable small private dams in California, however they have been under attack from the state and the state has been refusing to build or upgrade public dams for decades, while there are serious threats to existing public dams in the name of "environmentalism".
The only real efforts to "manage" water in CA is how will we transfer northern water to the south, and how much will be transferred?
There hasn't been STORAGE conservation efforts for decades.
Finally, California's large valley areas are rain shadow areas that fortunately have two major rivers that run through them, so "drought" is the standard pattern for California, but hurts only when you improperly manage your water.
“There hasn’t been STORAGE conservation efforts for decades.”
Beyond the lunacy that says you can double a state’s population but not do ANYTHING about increasing the supply of water, we have an antequated system that can’t impound the early rains AND the melting snowpack. So our reservoirs ( in normal years) fill up early with rainwater runoff early in the rainy season, a lot of which has to be released to make room for the melting snows in the Spring. If you look at graphs of storage facilities like Folsom, you can see easily how they have released rainwater this year to “make room” for the melting snow. And don’t get me going about the Delta Smelt and it’s impact on water storage.