Mighty Mississippi: A river's muddy dilemma

There was no emotion on 67-year-old Paul Watson’s face as he tacked the “FOR SALE BY OWNER” sign on his flood-ravaged home in New Orleans’ Lower Ninth Ward.

Victimized by Hurricane Katrina in August of 2005, Watson and other longtime residents here admit they’ve given up on rebuilding in this low-lying neighborhood bordered by the powerful waters of Lake Ponchartrain and the Mississippi River.

The reasons are understandable: Too much reliance on man-made structures that might collapse again in the next big storm; the forces of nature are just too risky.

Yet that’s been the fate of New Orleans ever since early settlers began changing the natural course of the Mississippi River with earthen dikes to protect homes and farms from flooding.

The federal government got involved in flood control in the late 19th century, and since then it has further diverted the river with a system of spillways, jetties, levees, canals, dams, reservoirs and pumping plants.

The river’s course also was changed to allow ocean-going freighters to dock at ports in south Louisiana in order to transfer cargo to and from river barges.

Now the Mississippi flows in a tight corridor outside its original channel, with the mouth of the river running deep into the Gulf of Mexico instead of spilling along the coastline.

Environmentalists said this means the 400 tons of mud and silt the river collects every year from its journey through 10 states ends up at the bottom of the Gulf and not as sediment deposits needed to sustain the shallow coastal wetlands of Louisiana.

The amount of so-called alluvial material is so enormous because the Mississippi River is the third largest watershed in the world, with rivers and streams from 41 percent of the continental United States draining into it. Only the Amazon River Basin in South America and the Congo River Basin in Africa are larger.

Before the system of levees and dams altered the river’s course near the mouth, it built up thousands of acres of coastal wetlands in Louisiana.

But environmental experts estimate that Louisiana has lost more than 1,100 square miles of wetlands along its coast in the past half-century due to the river’s unnatural course, and that between 25 and 35 square miles – an area the size of Manhattan in New York City - disappears every year.

This large loss of wetlands, the experts say, is a serious threat to shrimp, crabs, oysters and fish, and to migratory birds and 400 forms of wildlife that rely on the Mississippi River Delta habitat.

But it is also a danger sign for the nation’s petroleum industry. Twenty-five percent of our natural gas production comes from coastal Louisiana, and 18 percent of U.S. oil production, according to federal records.

“As wetlands and barrier islands disappear, the wells, pipelines, ports and roads that make the oil and natural gas industry possible will be exposed to open water conditions,” warns the Louisiana Department of Natural Resources. “These facilities will need to be replaced at a high cost, and the potential for damaging oil spills will increase.”