Delta Force
Banned
Underwater logging (no, really - it's a thing) would mitigate that. And, of course, the dam would take much longer than three years to build and fill, so at least some could be removed by traditional means.
From what I've read, only around 3% or so of the lumber would have been possible to extract before inundation. I'm not sure why, but I suppose having as many trees as Alaska logged in three years spread across an area at least the size of Lake Erie had something to do with that. However, apparently the prevailing water currents would have pushed most of the floating logs to one bank of the river for easy collection, which would have provided enough lumber to operate a sawmill for a few years.
I think that might be possible to mitigate, although it would have been quite expensive though, raising the price of power by several mills (tenths of a cent). Table 14 on Page 23 of the official environmental impact statement for Rampart illustrates this, as the price would have gone from 3.0 mills per kWh without mitigation in the first case to 5.4 mills per kWh with mitigation, and from 2.4 mills per kWh without mitigation to 4.2 mills per kWh with mitigation in the other. Rampart would have been the largest dam built under the environmental regulations of the 1970s, so it might have been possible to build it better for that than the dams that had to be retrofitted.Not saying it won't be an issue, but it wouldn't be the biggest. Now, completely buggering up salmon migrations on the Yukon... that would be problematic.
That said, there probably isn't any good way to mitigate the inundation of Yukon Flats.