Many of the primitive hydropower dams built a century or more ago have a production capacity which is negligible by modern standards. The two dams removed from

Many of the primitive hydropower dams built a century or more ago have a production capacity which is negligible by modern standards. The two dams removed from the Elwha river here in Washington were the lowest and third-lowest producers in the state; the capacity lost by decommissioning them was utterly overwhelmed by the new wind and solar capacity added in a single year. I don't recall precisely how much power the Klamath dams generated, but when I looked it up, though the numbers were larger, the overall situation was similar: the hydro capacity California lost was inconsequential given the growth in other renewable sources. It's not so much that the river needs to be restored to a particular point in time as that the river needs to actually be a river and not a lake, if it is to support a river-dependent ecosystem. Water temperature, flow rate, presence of shallows, shade, woody debris, and so forth are all environmental elements which have a large effect on the viability of a habitat for keystone species like salmon. You can't just fake it with fish ladders.