For thousands of years, the Mississippi River meandered through its valley unhindered, flooding lowlands and creating oxbow lakes when it changed course. But as men began to settle and develop the valley, they tried to place restrictions on the whims of the river and make it conform to their needs. Sometimes the river would cooperate, but many times it would not. Caving banks would claim buildings or valuable farmlands, the shifting channel would leave prosperous ports high and dry, and numerous floods devastated crops and economies.

More than a century ago, the Vicksburg District began working with the Mississippi River and its tributaries seeking their cooperation, but the present comprehensive program began after the disastrous flood of 1927. The work of the past half century has included cutoffs, floodways, reservoirs, and levees. Much of the ongoing work on the river-bank stabilization, dikes, and dredging-is performed to keep the river in the desired channel for navigation and flood control.

One of the largest of the Vicksburg District's operations is the annual revetment program. Using articulated concrete mattresses cast at fields in Greenville, Mississippi, and Delta Point, Louisiana, the district repairs and fortifies banks against the destructive, gnawing current of the river. For the revetments to be effective, they need at least two qualities- economy and strength. The present use of articulated concrete mattresses, is the culmination of 100 years of engineering evolution.

One of the earliest forms of revetment in the Lower Mississippi Valley was the willow mattress, woven by hand on site and weighted into place with stone. The willow mats were successful for several reasons. The main ingredient, willows, was abundant in most places along the river, and young willows could be woven into a mat that was flexible enough to conform to the irregularities of the bank. But the willows had their drawbacks-the tediousness of weaving the mats, eventual deterioration of the material, and, by 1910, the scarcity of willows.

Experiments with reinforced concrete as a revetment material began in Vicksburg in 1914, and the first successful reinforced articulated- concrete mattress was developed in 1917 and patented by D. H. Shearer. The 3-inch-thick concrete slabs were reinforced with a wire mesh extending on all sides. The 16-block mattresses are now cast in units of 13 uniform slabs and barged to the worksite as needed.

Prior to the placement of the mat, the bank of the river is graded to a stable slope using bulldozers and massive floating draglines. The units of reinforced concrete slabs are then assembled on the sloping deck of the sinking unit into mattresses 156 feet wide. The sinking unit is then moved out from the bank, allowing the completed sections to slide from the deck onto the bank. When mattress placement is complete, the graded area above the revetment is protected with a covering of stone riprap. This entire process costs about the same per square foot as laying good carpet in a home.

The articulated concrete mattress has attracted the interest of engineers from around the world. Each year, numerous foreign visitors come to the Vicksburg District during the work season to observe the process from beginning to end-from the casting of the mats through their assembly and placement on the banks of the mighty river. However, despite international interest, there is only one existing mat sinking unit, unique to the Mississippi River and operated by the Corps' Vicksburg District.

Though the river may seem tame to some, it still has a will of its own, fighting to go where it pleases. However, as long as there is a need, the Vicksburg District will continue to work with the Mississippi, developing the required technology to meet the needs of new challenges.