Some factors involved in the proposed Tuapeka Dam Facts and Figures COST It would cost too much to build in comparison to alternative methods of generating as much electricity. So you would need to cover only a tenth of the area to generate an equivalent amount. A dam at Tuapeka would be even worse, as new forms of generation become cheaper and less demanding environmentally. We say leave the rivers alone and develop alternative technology.
Wind is a good alternative.
There is no doubt that building dams creates jobs, but as the Clyde dam showed, mainly for people from outside the area. Furthermore it does not result in the landscape being destroyed. There are literally billions of trees in the area. Much of this is habitat to many rare species of birds and insects. Do not believe anybody who tells you this will not happen.