Its just breathtaking that that has not been happening.
Where I live, a large dam (4X Sydn harbour) has mitigated disastrous flooding. It will supply towns downstream for many years, and irrigate crops to feed thousands. Not to mention keeping wetlands viable, plus generating a small amount of clean free-for-the-taking power.
There are plenty of sites around the country and it is just irrational and irresponsible for any politician to be so selfish as to vote it down.