You enviro twits love to quote the Elwha...the difference is the Elwha is 45 miles long...55 inches of rain a year. The Klamath is 263 miles long, 29 inches of rain. The Elwha sediment bed was sand and coarse alluvials....only 2 to 3 feet deep. The Klamath reservoir beds average 3X that and are the very finest of clays, the kind that suffocate life...impermeable clay when dry.
Stick with airplanes.
