I wouldn't be so sure about it being fished out. It is a large lake with very little fishing pressure. Only one other guy said he had no success.
I've caught lots of fish there, not this year, but I doubt it is void of fish. When you think of lakes in WA. that are "Fished out" you may be thinking of "Put and Take" lakes. The lowland trout stocked lakes. they do take a beating on the trout supply, but that is what the trout are put there for.
Target some other species in the lower lakes, i.e. largemouth bass, panfish etc. There in there.