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- River engineering 80
- Bodies of water 77
- West (U.S.) 77
- Northwest, Pacific 76
- Railroad engineering 47
- United States--Appropriations and expenditures 5
- River surveys 4
- Locks (Hydraulic engineering) 3
- Canals--Design and construction--Costs 2
- Dams--Design and construction 2
- Cascade Range 1
- Railroads--Design and construction 1
- Rivers 1
- Transportation 1
