Russ:
Not too long ago public entities would pay for all or part of your pond construction. That all changed when the realization dawned that there was just so many gallons of water and that all of it was "spoken" for. In other words, if more gallons were stored and removed from the downstream access there would be shortages for the folks (wineries) who were dependant on it. That is a simple explanation for a complex and ugly problem facing most of the western states. It is the primary reason why growth is limited, there just isn't enough water to go around. Now we are seeing lots of discussion about desalinization - I'm pretty sure there is enough water in the Pacific Ocean - the crazies however are worried about salt discharges, so who knows how long that crap will delay sensible solutions to real problems.
Jim