In the Mississippi valley water is taken from the river by flumes in the levees or by siphons.
Nearly all of this vast flood-plain lies below the level of high water in the Mississippi, and, but for the protection afforded by the levees, every considerable rise of its waters would inundate vast areas of fertile and cultivated land.
The task of maintenance consists almost entirely in closing the gaps which occur when the banks on which the levees are built cave into the river.
Built in part upon "made land," well protected by levees, and lying within the richest cottonproducing region of the south, the rich timber country of the St Francis river, and the Mississippi "bottom lands," Helena concentrates its economic interests in cotton-compressing and shipping, the manufacture of cotton-seed products, lumbering and wood-working.
Some of the levees, especially those in swampy regions where outlet bayous are closed, are of extraordinary solidity and dimensions, being 20 to 40 ft.