“How do you store water on what is essentially a table top?”
While it’s flowing down the various regional rivers, you pump a much of it as you can up to reservoirs in the hills that ring the valley.
That is how Los Vaqueros reservoir in east Contra Costa County is filed. They can run the pumps full bore when the flow is high like it is right now. The greatest mitigating factor is there aren’t three dozen other reservoirs around in area hills equipped to do the same.
Conserve water involves that extremist part of speech.. part of conservative.