Another of the Mississippi River Delta region’s industrial infrastructures is the Gulf Intracoastal Waterway, which stretches 1,109 miles from Apalache Bay, Florida to Brownsville, Texas. In the image above (which is rotated so that north is on the right, Port Arthur at the top, and New Orleans at the bottom), the Waterway is clearly visible as an artificially straight waterway dug parallel to the Gulf Coast but inland. (Just south of Port Arthur — near the top of the image — it passes off the image to the north (right), re-entering on the eastern (lower) side of Calcasieu Lake.)
The US has a surprisingly limited number of waterways which carry heavy quantities of commerce. (Well, it surprises me.) The Census’s Statistical Abstract lists only six (or seven, depending on how you count): the Mississippi River system (which includes both the Mississippi and the Ohio; that’s where you get six or seven), the Columbia River, the Snake River, the Great Lakes system, and the two intercoastal waterways, the Atlantic and the Gulf. (Of course, the other way to look at this would be to note that those seven waterbodies intersect the great majority of the states in the Union.) The Mississippi River system dwarfs the others, carrying more tonnage than the other five combined, while both the Atlantic Intracoastal Waterway and the Snake carry relatively insignificant tonnage. The Gulf Intracoastal Waterway lies in between these extremes, carrying somewhere over a hundred million tons of freight annually.
Like the rivers and the Great Lakes, the Intracoastal Waterways are partially natural and partially infrastructural systems, with locks, canals, levees, and dredged navigation channels opportunistically connecting both existing waterbodies and sheltered expanses of Gulf and Ocean behind barrier islands.