Aging Loch News Today

With aging loch, levees and dams that require constant work just to keep critical barges and ship traffic moving. >> reporter: 500 tons of cargo move on this massive river, including half of all u.s. grain exports. the army corps of engineers is constantly dredging the river to keep it moving. but some dams and levees are getting old and need replacing. the waterways get a d-plus but some of the countrys dams and levees get a d. >> the port of new orleans is the countrys sixth busiest, but it ca...