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Topic
- United States--Appropriations and expenditures 50
- West (U.S.) 49
- River engineering 46
- Transportation 34
- Canals--Design and construction--Costs 32
- Dams--Design and construction 32
- Bodies of water 27
- Northwest, Pacific 25
- Rivers 25
- Water resources development 25
- River surveys 24
- United States. Congress--Records and correspondence 11
- Locks (Hydraulic engineering) 8
- Government publications 4
- Maps 3
- Railroad engineering 3
- Bridges--Design and construction 2
- Cities and towns 2
- Discovery and exploration 2
- Explorers 2
