looking this up I see that npr says CA used 20 to 30% of its water on the smelt. Is that true?
800k acre feet would have been gone in a month. And the delta's water has fallen so far in any case that it no longer reaches the pumps and couldn't be diverted even if CA wanted to reverse course on the smelt.
The smelt represent the overall condition of the environment, and a temporary (we hope) crisis like a drought is not a good enough reason to make permanent, harmful changes to the environment. The line must be drawn somewhere.