Come what may, rain and snow will fall in the mountains. Given the natural proclivities of water responding to gravity, the runoff will flow downhill to the sea.
If we dam the canyons we can generate power with the falling water. These lakes are also useful for recreation, flood control, and irrigation.
The region I live in in WY gets most of its electric power from the Bonneville Power Administration. Our power is cheap, plentiful, and creates zero carbon pollution.
Unlike wind and solar, hydroelectric power is available 24-7. Unlike solar fields and wind turbine fields which are often eyesores, hydroelectric lakes are picturesque.
Somebody who isn't a tree-hugger tell me why we aren't planning to build lots more hydro projects.