Land and Levees Laurel Valley Sugar Plantation, Thibodaux Louisiana
Of all the southern states possibly nothing sets Louisiana apart more from its neighbors than its land. For over 15,000 years, the state has had the Mississippi River as its chief architect. The river has shifted its course, swinging first to one side of the state, then to the other, and then back down through the center. There have been seven major shifts within the state. But each shift has had beneficial result, altering the landscape and leaving behind tons of alluvial soil carried down from the central part of the United States. Moreover, shifts also left behind small distributary streams or bayous which often repeated the Mississippi River pattern. Thus, a deltaic plain developed from the head of the Atchafalaya River to the Pearl River Delta in the east and to the mouth of the Vermillion River on the west. It represents about 13,000 square miles or nearly thirty percent of Louisana's land. The alluvial deposits, wholly within Louisiana, extend to a depth of more than fifteen feet. So much alluvial soil has been deposited in only a few parts of the world.
Laurel Valley lies within the Mississippi Deltaic Plain. Its lands are made up alluvial deposits dropped more than a thousand years ago when Bayou Lafourche served as the main channel of the Mississippi. But when the Mississippi shifted to its present course, it left a natural levee system that sets off the Lafourche region from other areas within the deltaic plain. Besides being the most recent, the Lafourche natural levees are the highest and widest sloping back from the water's edge nearly three miles. Centuries of flooding produced the levees. Silt and sand settled out-beyond the banks, gradually building up the area. Coarse heavy materials dropped first, forming the best drained and richest land. Finer sediments settled out farther back from the Bayou, near the swampy lowland, creating a heavy, clay-like soil that drains poorly.
The sloping lands attracted early settlers, especially those wanting to cultivate sugar cane. They found that the natural levees, having a solid composition, proved so prodigiously fertile that many believed their fertility inexhaustible.
But the natural levees posed one problem. They provided riparian landowners insufficient protection during high water. The lower Mississippi Valley filled up quickly after unusually heavy rains in the midwest or when winter snows melted rapidly. The natural levees could contain moderate amounts of water, but unusually large amounts sometimes came over the banks or, even worse, broke through, causing a crevasse. When this happened, according to an early traveler, the water rushed "from the river with indescribable impetuosity, with a noise like the roaring of a cataract, boiling and foaming, and rearing everything...." Then, up and down the waterway, residents rushed to halt the destruction. They stopped an overflow by piling more dirt on top the banks; if crevasse had occurred, they drove double rows of pilings on each side of the break to form a circle. Then they wove twigs and branches into the pilings, later filling and sealing the breaks with, larger branches, trees and dirt.
In the beginning the construction of protective levees for the fertile alluvial soils was haphazard. In 1743, French officials required each land owner to maintain his own levees; the Spanish later continued this policy. More often than not, the economic standing of the riparian land owner determined construction size and techniques. As a consequence, no uniform standards existed as to levee height, width, or material. Throughout Louisiana levees varied from 40 to 120 feet back from the natural bank, 4 to 6 feet high, 6 to 9 feet wide at the base. Sometimes levees were shored up by driving cypress planks down through the crown of the levee. Sometimes landowners used interior drainage ditches to remove water that caused soft areas in the levees. In other instances trees or Bermuda grass were planted to protect the soil from surface abrasion and erosion.
This individualistic policy of the colonial period gradually gave way to a more centralised control after Louisiana became a state. In 1816, in the first of many statutes, the legislature enacted a comprehensive levee and road law granting parish governing boards police juries complete control of levees on their parish. In Lafourche Parish, for example, the jury required riparian landowners to maintain what was called the Creole Levee: "The crown was to be at least 4 feet wide, the slope of base not less than 2 to 1 for a perpendicular depth of 3 feet and thence to the ground, for each foot in depth, and increase of base on each side equal to the distance of the upper face from the crown." The police jury dispatched inspectors periodically to determine if any sections of the levee were in disrepair. Inspectors could order work done to repair weak spots, and the police jury could then sue the landowner "for whose account the said work or repairs were made." In 1879, the legislature passed enabling legislation for uniform construction practices along inter-parish waterways. It empowered parishes to establish levee districts beyond their political boundaries and to pass the improvement costs on to all who benefited. Further changes in policy in the twentieth century increased the role of the federal government. In 1917, the Federal Flood Control Act gave the United States Army Corps of Engineers many responsibilities formerly held by the levee districts.