AFAIK there is no shortage of salmon however is an unmet need for massive amounts of electricity and hydro is about as environmentally friendly as it gets.

There actually is a shortage. Several runs of Columbia salmon are either endangered or threatened, and therefore are protected by law. The situation is very complicated, but tribes have a legal claim to the salmon fishery and the dams are causing them economic damage. The dams have economic value, but mitigating the effects of the dams on salmon is costing billions of dollars. Some of those are tax dollars, by the way. This lowered the economic value of the dams to nearly zero from a power generation standpoint. There is value from a transportation standpoint, however.

After decades of expensive and fruitless lawsuits, all the stakeholders got together and after a lot of blood sweat and tears hammered out a deal. The deal did not require removal of the dams, but did create a pathway that would end all the lawsuits. The tribes are on board, and critically the owner and operator of the dams, Bonneville Power is on board too. Now everyone is on the same page and we can arrive at a solution that benefits everyone.

Not so fast. Trump tore up the deal that all the stakeholders wanted, so we're back to lawsuits and expensive and ineffective mitigation measures.