Interesting idea. I remember reading some years ago about a species of water lily that is remarkably effective in using certain forms on industrial waste as food. The lilies purify the polluted water they grow in, and - IIRC -the flowers themselves can be processed into feed or fertilizer.
Interesting idea, hopefully it works. The real reason why the Willamette is so silty has to do with the dams not allowing it to clean it’s channel. If a deep channel was dredged it would provide faster flow in the low water months which would prevent the river from silting. This would also provide better spawning habitat for salmon and not suffocate so many eggs.
Back when we used to dredge the river, it allowed commerce to flow from the Pacific all the way to Eugene, and we had HUGE runs of salmon. Just think of the eco-tourism having a passable channel would create.
Obviously, the blackberries are native.
Great idea...until someone starts to harvest the contaminant-laden mushrooms to sell to local restaurants “for cheap”?