"Navigation on our three rivers."; "United States. Army. Corps of Engineers. Pittsburgh District."; "Locks (Hydraulic engineering)--Pennsylvania--Pittsburgh Region--Maps.", "Dams--Ohio River--Maps.", "Locks (Hydraulic engineering)--Allegheny River (Pa. and N.Y.)--Maps.", "Locks (Hydraulic engineering)--Ohio River--Maps.", "Locks (Hydraulic engineering)--Pennsylvania--Pittsburgh Region--Pictorial works.", "Locks (Hydraulic engineering)--Monongahela River (W. Va. and Pa.)--Maps.", "Dams--Monongahela River (W. Va. and Pa.)--Maps.", "Dams--Allegheny River (Pa. and N.Y.)--Maps.", "Boats and boating--Pennsylvania--Pittsburgh Region--Maps.", "Dams--Pennsylvania--Pittsburgh Region--Maps."; "United States. Army. Corps of Engineers. Pittsburgh District."; "undated"; "

Brochure.

"; ""; "P21113"; "pec"; "Locks (Hydraulic engineering)--Pennsylvania--Pittsburgh Region--Pictorial works.", "Locks (Hydraulic engineering)--Pennsylvania--Pittsburgh Region--Maps.", "Dams--Allegheny River (Pa. and N.Y.)--Maps.", "Dams--Monongahela River (W. Va. and Pa.)--Maps.", "Locks (Hydraulic engineering)--Monongahela River (W. Va. and Pa.)--Maps.", "Locks (Hydraulic engineering)--Ohio River--Maps.", "Dams--Ohio River--Maps.", "Dams--Pennsylvania--Pittsburgh Region--Maps.", "Locks (Hydraulic engineering)--Allegheny River (Pa. and N.Y.)--Maps.", "Boats and boating--Pennsylvania--Pittsburgh Region--Maps."; "14256"; .