[The twin Atchafalaya river ports of Morgan City (on the east bank) and Berwick (on the west bank), captured in false-color by the “Advanced Spaceborne Thermal Emission and Reflection Radiometer” on NASA’s Terra earth-imaging satellite, May 27, 2011 — after the second opening of the Morganza Spillway.]

Old River Control sits at the northern end of the Atchafalaya River; at the southern end, in the brackish waters of Atchafalaya Bay, a similarly massive wall of concrete protects a port: the Morgan City Floodwall.

[The Morgan City Floodwall on 20 May 2011, via the Times-Picayune.]

[The floodwall on a drier day; photograph by flickr user milepost36.]

Like the river ports of the Mississippi, Morgan City exists because of the confluence of hydrology and industry: first oysters and shipping, then laden with sawmills as the center of America’s cypress industry when the big old-growth cypresses of the Atchafalaya swamp were logged, later shrimp harvesting, and, finally, oil.  (Even the city’s name reflects this history: it was named after Charles Morgan, a nineteenth-century New York shipper, who moved his Louisiana business to the nascent port — then known as Brashear City — to escape both growing competition and increasingly expensive fees in New Orleans.  He brought both rail lines and steamboat lines to the city, and the intersection of those lines with the Atchafalaya River rapidly produced prosperity in the city.)

[Map from a 1982 Army Corps of Engineers report, showing the position of the Eastern and Western Guide Levees.  The approximate extent of the Morgan City Floodwall is shown in red.]

[The Floodwall from above, via Bing Maps.]

When the Morganza Spillway was opened this past May, releasing Mississippi floodwaters into the Atchafalaya Basin, those waters were eventually headed for Morgan City, channeled by the two great levees of the Atchafalaya Basin, the Eastern Guide Levee and the Western Guide Levee.  The Morgan City Floodwall is a small dash along the line of the Eastern Guide Levee, twenty-two feet of concrete interrupting the generally monotonous earthen character of the levee, an interruption whose bulk imagines, as John McPhee says, water — “a sheet of water at least twenty feet thick between Morgan City and the horizon”.