Mark Tercek and Jonathan Adams
It is one thing to think about taking out levees, but quite another to figure out where and when and how. The Ouachita River north of Monroe, Louisiana, provides a perfect opportunity to show the benefits of restoring floodplains.
The effort centers on a small stream called Mollicy Bayou in the northwest corner of Morehouse Parish. The bayou fed the Ouachita from about 25 square miles of bottomland forest on the river’s east side. Thomas Jefferson sent surveyors to the area in 1804, after the Louisiana Purchase added the land to U.S. territory. Low-lying and wet, dotted with sloughs and lakes, settlers found the area less than ideal for farming, so they cleared other areas first for their small farms and later for the larger cotton plantations.
The land remained wild and for a time was a state game preserve. Not until the late 1960s, with growing demand for soybeans, did anyone try to farm the land around Mollicy Bayou. Private investors bought and cleared a neat rectangle about 8 miles long and 3 miles wide, piling the cut trees in heaps and burning them in enormous bonfires. The new owners quickly realized they would need levees and pumps to keep the land anything close to dry enough to plant. They built some 17 miles of levees that nearly surrounded the property.
The levees, 30 feet tall and 150 feet wide at the bottom, kept the Ouachita floodwaters off the soybean fields, now called Mollicy Farms. Unfortunately, they also kept rainwater on them. Where the farmers had dug up the soil needed to build the levee, they left behind an enormous borrow ditch and every time it rained hard, a common event in northeastern Louisiana, first the ditch and then the rest of the land would start to fill like a vast bathtub. The land managers had to turn on the pumps and dump tons of water laden with fertilizer and topsoil back into the river.
Despite the impressive engineering, after several farmers went bankrupt in the 1960s it became clear that the soggy bank of the Ouachita was not the best place to grow soybeans. Not easily deterred, and still looking to recoup the investment in miles of levees, the owners decided to try growing rice instead. This enabled them to focus on keeping the crop wet instead of dry, but it was still a hard slog. More farmers went under. By the mid-1990s, the only economically sensible option was to sell, and the only buyer ready to pony up cash for unfarmable land was the U.S. Fish and Wildlife Service.
The service already owned a large piece of land just across the river from Mollicy Farms, the Upper Ouachita National Wildlife Refuge. Here you can still see how Mollicy Farms, and indeed thousands of square miles of the Lower Mississippi River Alluvial Valley, once looked. Floods regularly sweep in among the trees of the wildlife refuge, in places climbing 20 feet or more up the trunks.
The floodwaters deposit silt, thus renewing the soil and forests, and then recede quickly enough to avoid killing the established trees. The water also allows fish to leave the mainstem of the river to search for rich sources of food; wade into the forest in a low flood and you will be tempted to scoop the fish up in your hands. People in the region understand how the ecosystem should function, the give-and-take between the Ouachita and the bottomland forest, a rich and complicated relationship that supports ducks and wading birds, cottonmouths and alligators, wild turkeys, deer and black bears. . . .
http://magazine.nature.org/features/natures-fortune.xml
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