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- Water resources development 38
- Bodies of water 32
- Northwest, Pacific 32
- Rivers 32
- Transportation 30
- West (U.S.) 30
- Canals--Design and construction--Costs 29
- Dams--Design and construction 28
- American wit and humor, Pictorial 6
- Oregon--Politics and government 6
- United States--Politics and government--1933-1953 6
- United States--Politics and government--Caricatures and cartoons 6
- World politics--Caricatures and cartoons 6
- Conservation of natural resources 3
- Locks (Hydraulic engineering)--Oregon 3
- Water-power 3
- Fisheries 2
- Maps 2
- Wildlife conservation 2
- Agriculture 1
