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- Locks (Hydraulic engineering) 9
- United States--Appropriations and expenditures 7
- Dams--Design and construction 6
- River engineering 6
- Canals--Design and construction--Costs 5
- River surveys 4
- West (U.S.) 3
- Bodies of water 1
- Cascade Range 1
- Dams 1
- Railroad engineering 1
- Rivers--Oregon 1
- Transportation 1
