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- Dams 17
- Flood control 17
- Rivers--Oregon 17
- Fishes--Conservation 4
- Salmon 4
- Inland water transportation 3
- Irrigation 3
- Water--Pollution 2
- Birdhouses 1
- Izaak Walton League of America 1
- Lectures and lecturing 1
- National Wildlife Federation 1
- Oregon Audubon Society 1
- Pacific College (Newberg, Or.) 1
- Sewage disposal plants 1