Get rid of them. The loss of ultra clean renewable electricity; billions of dollars for demolition; hundreds of millions and 30 years for removal of silt, mud and debris built up in the dam’s forebays; no more barge traffic to transport grains, produce, supplies and fuel; no more irrigation for potatoes, beets, tree farms, grapes, etc.; much-reduced boating, camping and recreational activities and few boat ramps; no cross-river traffic over the dams; loss of most marinas; vineyards would return to weeds and sagebrush; loss of barges would put hundreds of semi-trucks on the roads, daily plus extra shipping cost; loss of employees on farms/ranches; loss of payroll of dam employees, suppliers and support people; loss of their monies for stores, shops and communities; no more flood control.
Remember (you probably don’t) the flooding of Portland? Twice.