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- Northwest, Pacific 6
- Dams 2
- Maps 2
- Photography 2
- River engineering 2
- Rivers 2
- Transportation 2
- United States. Congress--Records and correspondence 2
- Aerial photographs 1
- Agriculture 1
- Bodies of water 1
- Bridges 1
- Bridges--Design and construction 1
- Canals 1
- Exports 1
- Formations (Geology) 1
- Government publications 1
- Harbors 1
- Hydroelectric power plants 1
- Industrialization 1