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Topic
- Rivers--Oregon 14
- Dams 9
- Flood control 6
- Water--Pollution 6
- Salmon 4
- Fishes--Conservation 3
- Lectures and lecturing 2
- Oregon Audubon Society 2
- Bears 1
- Degrees, Academic 1
- Eels 1
- Inland water transportation 1
- Irrigation 1
- Izaak Walton League of America 1
- Oregon State College 1
- Sewage disposal plants 1
