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Topic
- Bodies of water 16
- Dams--Design and construction 16
- Rivers 16
- West (U.S.) 16
- Canals--Design and construction--Costs 15
- Transportation 15
- Northwest, Pacific 13
- Water resources development 13
- River engineering 10
- River surveys 10
- United States--Appropriations and expenditures 10
- United States. Congress--Records and correspondence 4
- Locks (Hydraulic engineering) 3
- Boats and boating 2
- Docks 2
- Inland navigation 2
- Sailing ships 2
- Steamboats 2
- Abandoned buildings 1
- Astoria Seachannel 1