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. – See more at: http://magazine.nature.org/features/natures-fortune.xml#sthash.81QusJRo.dpuf
The Fish and Wildlife Service began buying up parcels of Mollicy Farms in the 1990s and adding them to the refuge. But the new acreage bore hardly any resemblance to the land across the river—a fact not lost on two brothers, Kelby and Keith Ouchley, who grew up near Monroe and knew the woods and waters around Mollicy Farms well. Both had strong conservationist streaks. Kelby, the older of the two, eventually became manager of the wildlife refuge, while Keith got a doctorate in wildlife ecology from Louisiana State University and took over the Louisiana chapter of The Nature Conservancy in 2001.In those roles, the Ouchley brothers were in a unique position to take on a grand experiment. Kelby managed wetlands projects for the Fish and Wildlife Service and had been instrumental in purchasing Mollicy Farms. The agency initially had in mind not a full-blown restoration of the floodplain but instead a more straightforward, though still ambitious, reforestation effort: replanting 3 million native trees, such as cypress, water tupelo, willow oaks, green ash and mayhaws.In 2007, the best place to admire the progress was from atop the levees, but as the Ouchley brothers turned west to look over the intact forest of the refuge, they knew they were standing on the most important obstacle to a functioning floodplain—for people and for natural communities alike.The levees would have to go.Taking out a levee is a complicated business, especially at this scale. Tearing down all 17 miles of levees was out of the question; the expense of moving so much earth would be astronomical. But even punching holes in something that large is daunting. Keith Ouchley says he and his brother considered dynamite until they realized that the blasts might shatter windows from Shreveport, Louisiana, to Jackson, Mississippi. Although the Corps of Engineers does not own the levees around Mollicy Farms, it is responsible for the levees that guard Monroe, and would have been most unhappy with the Ouchleys had they put those at risk. – See more at: http://magazine.nature.org/features/natures-fortune.xml#sthash.81QusJRo.dpuf
Once the Ouchleys moved past the dynamite idea, their only option was to bring in dump trucks, backhoes and scrapers like those used to grade roads, and gradually whittle the levees down in spots until they were level with the river. A more difficult question then arose: where to breach the levees. Getting the answer falls in the domain of a highly specialized field called fluvial biogeomorphology. That mouthful requires computer models, topographic data and aerial survey maps, along with an understanding of the ecology of the bayous.The result of all the science was a plan for four cuts in the levees, each about 1,000 feet long, at the points where existing or historic streams entered or exited the property. The Fish and Wildlife Service supplied the muscle. The project was eminently shovel-ready, so the federal government chipped in $2.6 million in stimulus money to complete the work.The breach was scheduled for June 2009, but the Ouachita had its own plans. By mid-May, the river reached the top of the levees. The Ouachita then began flowing over the levees and ultimately burst through in two locations, blowing out two 150-foot gashes. Knowing nothing of fluvial biogeomorphology, the Ouachita made the cuts where it pleased, not where the scientists selected. The river also dug a new lake 60 feet deep and uprooted many of the newly planted trees – See more at: http://magazine.nature.org/features/natures-fortune.xml#sthash.81QusJRo.dpuf
Once the floodwaters receded, work on the planned breaches (the natural ones remained in place, too) began in the summer of 2010. Heavy machinery pushed the earth back into the borrow ditch whence it came, reconnecting the tract’s bayous to the Ouachita. Returning the muddy river to its ancient floodplain would become the biggest levee-busting operation ever in North America.
The Ouchley brothers are in the early stages of a plan to coax plants and animals back to flourishing as they had when Jefferson’s surveyors measured the landscape in 1804. In 50 years, visitors to the former Mollicy Farms will see a hardwood bottomland forest with abundant wildlife and flowing water. From atop what remains of the levees at high water, Mollicy Farms now looks like a large, placid lake. That illusion is easier to maintain if you ignore that it is a lake filled by a raging Ouachita, which at flood stage is a torrent nearly 30 feet deep. The former farm now stores floodwater and takes pressure off the downstream levees.
The return on this investment will not be just in the local environment’s improved health, but in the lessons it has for other places as well. Kelby Ouchley likens the whole process—from replanting trees to removing the levees to replumbing the floodplain—to angioplasty.
Scientists from Duke University have added up how much all this could be worth—carbon sequestration, recreation, flood protection and so on—both to the people living nearby and to those on the Gulf Coast and even farther away. Breaching the levees and restoring the forest may make more economic sense than eking out marginal row-crop agriculture. In a 2009 study the researchers totaled all these values across the Mississippi alluvial valley and found that wetlands could be worth up to two and a half times more intact than they would bring if converted to soybeans or cotton.
It will take some time before all those arteries are clear and the patient is healthy again. Healthy here is also a relative term. Given how the land around Mollicy Farms was transformed, bringing it back to be indistinguishable from its twin across the river may be too much to ask, at least for now. That may not be the point. A living floodplain may be enough.
There truly are no losers in the restoration of Mollicy Farms. Private landowners had tried and failed to farm the land, sold it, and it is now in public hands. The levees themselves were built not by the Army Corps of Engineers but by the investors, and removing them increased the risk for no one and decreased it for many thousands of people in Monroe. A better example of a win-win would be hard to find. So it is not surprising that no one in the area objected to the plan to breach the levees. Most people were all for it. In part, this simply reflects the near-universal popularity of hunting and fishing in northern Louisiana. Who could object to 25 square miles or so of new hunting and fishing grounds? – See more at: http://magazine.nature.org/features/natures-fortune.xml#sthash.81QusJRo.dpuf
That no one in northern Louisiana objects to taking out a levee and flooding an old farm is important. The public response to removing the levees may represent a deeper and more profound shift. Over the past decade, dramatic floods in many places, not just in the United States but around the world, have forced us to rethink our relationship with rivers and to realize that our control over them is tenuous and may indeed be slipping. Scientists now know much more about how rivers and floodplains work. That knowledge enables people to work with nature to enhance both human well-being and the health of rivers at the same time. – See more at: http://magazine.nature.org/features/natures-fortune.xml#sthash.81QusJRo.dpuf
In Louisiana, some financial holes are best filled with water.