Columbia subject headings:
Harvard subject headings:
Dams--Mississippi River--History--20th century.
Dams--Mississippi River.
Locks (Hydraulic engineering)--Mississippi River--History--20th century.
Locks (Hydraulic engineering)--Mississippi River.
Mississippi River--Channelization--History--20th century.
Mississippi River--Channels.
Princeton subject headings:
Dams--Mississippi River--History--20th century.
Locks (Hydraulic engineering)--Mississippi River--History--20th century.
Mississippi River--Channelization--History--20th century.