Mile 950.5 - 950.5 - 945.5 RBD Pritchard Revetment

950.5 - 945.5 RBD Pritchard Revetment

Revetments are protective works designed to retard or halt the attack of currents against the banks of the river. They help preserve waterfronts, levee systems, and other flood control and navigation works. There are more than 600 miles of revetment work along the Lower Mississippi River. They consist of articulated concrete mattresses, laid under the water, with stone or riprap paving above the waterline. A bank-grading unit prepares the river's banks for the protective work, and a mat-sinking unit assembles the mattress on the spot and lays it in the water. On the Lower Mississippi, where almost everything is on a grand scale, erosion problems naturally assume gigantic proportions. It took more than half a century of experimentation for the Army Corps of Engineers to develop the methods and the machinery used today to produce the articulated concrete mats that stabilize the river's caving banks. It has been estimated that when the river attacks an unprotected bank it can erode as much as 600 feet of good earth in a year's time. Even a moderate attack by river currents can eat up 30 to 70 feet of river bank annually. The soil that disappears as the banks cave away soon reappears as sand and silt temporarily suspended in the water. When the load becomes too heavy, the river drops it, and it forms sandbars, towheads, or islands. In the past, small towns have been totally destroyed by the river.