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Posted sign under water in Delta
9.06.02
Science and Health:
Losing Ground
More on This Story:
Delta Overview

The Mississippi River delta is disappearing. One of America's most vibrant and productive ecological regions is slipping into the Gulf of Mexico at an alarming rate. Every year, a chunk of land nearly as big as Manhattan crumbles and washes away. As it erodes, it not only threatens one of the country's most abundant fisheries and a vital home for wildlife, but it imperils the nation's energy supply. And, as the coast of Louisiana continues to slip away, tens of thousands of lives are at risk from devastating hurricanes. The crisis in the delta could reach catastrophic levels in the next few decades, with far-reaching environmental, human, and economic consequences.

NOW presents the story of the disappearing delta in two parts: "Losing Ground," uncovers how one of the biggest civil engineering projects in U.S. history — the leveeing of the Mississippi River — has brought Louisiana and the nation to the brink of what could be the most costly environmental disaster in history.

"The City in a Bowl," NOW with Bill Moyers returns to the Mississippi River delta to examine another ominous effect of this crisis — the risk that a massive hurricane could drown New Orleans gets worse every single year.

Below is a primer on what is causing the delta to disappear — and what's happening when humans try to stop the process.



The Mississippi and it's tributaries
The Mighty Mississippi

The Mississippi is well worth reading about. It is not a commonplace river, but on the contrary is in all ways remarkable. --Mark Twain, LIFE ON THE MISSISSIPPI
Back in 1883, Mark Twain cited numerous examples of the Mississippi's grandeur and importance in an effort to get his countrymen to take an interest in their great river: The Mississippi, Twain told them, drains thirty-eight times as much water as the Old World Thames; it drains water from 41 of the lower 48 states; and it is the "crookedest" river in the world, "using one thousand three hundred miles to cover the same ground that the crow would fly over in six hundred and seventy-five."

In fact, the Mississippi is one of the largest watersheds in the world, covering more than 1.2 million square miles and stretching, in its entirety, 2,350 miles from its headwaters to the Gulf of Mexico. The waters and wetlands of the Mississippi are home to over 400 species of wildlife and 40 percent of North America's migratory waterfowl. Twain also noted the river's importance in North American history and lauded its qualities as a working river; there has been human habitation along its banks for 10,000 years, and European explorers and settlers quickly realized its agricultural, economic, and military importance. Today, millions of tons of cargo are shipped down its waters each year, and the river is integral to a host of jobs in agriculture and the fishery industry. And Mississippi River tourism dollars are estimated at over $15 billion a year.

Mississippi River delta
The Delta

The river annually empties four hundred and six million tons of mud into the Gulf of Mexico — which brings to mind Captain Marryat's rude name for the Mississippi — 'the Great Sewer...' The mud deposit gradually extends the land ... it is much the youthfulest batch of country that lies around there anywhere. --Mark Twain, LIFE ON THE MISSISSIPPI
The (relatively) youthful land to which Twain referred is the delta. The vast river system of the Mississippi and its tributaries carries with it tons of sediment, and it is this alluvial system that created the wetlands in southern Louisiana. According to Oliver Houck, director of the environment program at Tulane University Law School, "It would take 200,000 dump trucks — every day — on the roads [to bring] that [amount of] soil in. The Mississippi River built five million acres of south Louisiana. It built 20,000 square miles of south Louisiana. It built everything you see between Texas and Mississippi and inland about 50 miles. All of that's care of and thanks to the Mississippi River."

What does all that silt and water mean for the Louisiana coast? Take a look at these figures:

  • 3 million acres of coastal wetlands.
  • Over 40 percent of the salt marsh in the contiguous United States.
  • As much as 16 percent of the nation's fisheries harvest, including shrimp, crabs, crayfish, oysters, and many finfish, comes from Louisiana's coast.
  • There are more fishery landings than any other state in the conterminous United States (more than 1.1 billion pounds per/year)
  • Over 75% of Louisiana's commercially harvested fish and shellfish species are dependent on wetlands.
  • The area provides a habitat for over 5 million wintering waterfowl annually.
  • Louisiana's wetlands are home to many endangered species.
And then there are the economic benefits.

Levee along the Mississippi
Life Along the Levee

10,000 River Commissions, with the mines of the world at their back, can not tame that lawless stream, cannot curb it or confine it, can not say to it, Go here or Go there, and make it obey; cannot save a shore which it has sentenced; cannot bar its path with an obstruction which it will not tear down, dance over and laugh at. -- Mark Twain, LIFE ON THE MISSISSIPPI
Twain remarked on the seeming futility of controlling the Mississippi in 1883. That was just a few years after Congress established the Mississippi River Commission to combat flooding. Settlers had early on begun to construct levees (from the French lever, "to raise"), artificial earthen banks designed to protect homes and farms from flooding - a phenomenon they'd been witnessing for generations. But only with the advent of the Commission did the federal government take responsibility for taming the Mississippi.

The Commission's first 40 years were spent adhering to a "levees only" policy which attempted to contain the river and push the floodwaters into the Gulf of Mexico. The engineers did not make use of outlets or reservoirs, or even the natural outflow channels, instead constructing banks up to 40 feet high in some places. The devastating flood of 1927 led them to rethink that policy.

Today, the Army Corps of Engineers still uses levees along the Mississippi, but it also employs floodways, channels, dams, reservoirs, and pumping plants to handle excess water. The levee system is also still in operation and stretches nearly 2,203 miles.

Delta land loss
Land Loss

Louisiana accounts for 80 percent of the nation's coastal land loss, with rates ranging between 25 and 35 square miles per year. Over the past 50 years, more than 1,000 square miles of Louisiana have crumbled and turned to open water - that's an entire football field every half hour. Some of this loss can be blamed on the levee system, which has channelled water and sediment into the Gulf of Mexico instead of depositing them on the coastal wetlands.

The construction of an extensive levee system along the Mississippi River from the 1950s to the 1970s, with the goal of maintaining navigation and reducing the flooding of adjacent homes and businesses, has prevented the coastal wetlands from receiving their regular nourishment of riverine water, nutrients, and sediment, a diet critical to wetland survival. These regional impacts are exacerbated by other hydrologic alterations that have modified the movement of fresh water, suspended sediment, and saltwater through the system. Canals dredged for navigation, or in support of mineral extraction, have allowed saltwater to penetrate into previously fresh marshes. The current regulatory climate, along with improved technologies, prevents similar problems today; however, the damage already done continues to render local areas less able to combat subsidence and more susceptible to saltwater intrusion.

According to the Louisiana Department of Resources Office of Coastal Restoration and Management, if the current land loss rates continue unabated, by the year 2050, Louisiana will have lost more than 527,000 acres of coastal wetlands. That means that the Gulf of Mexico will move inland more than 30 miles, and New Orleans and other coastal cities will be open to the full force of Gulf weather.

Projections also include a large drop in fish harvests (30 percent), and huge loss of both jobs and agricultural, petroleum, and manufacturing products. The list continues, with threats to water supplies and transportation systems (Louisiana is first in the nation in tons of shipping). Many Louisianans also worry that the unique coastal cultural and ethnic communities - Cajun, American Indian, African American, French, German, and Italian - will be forever lost.


Sources: Louisiana Department of Natural Resources: Office of Coastal Restoration and Management; Coast 2050: Louisiana Department of Natural Resources; U.S. Army Corps of Engineers: The Mississippi River and Tributaries Project; Mark Twain, LIFE ON THE MISSISSIPPI, 1883; AMERICAN EXPERIENCE: "Fatal Flood"; Caernavon Freshwater Diversion; Center for Global Environmental Education

Losing Ground is produced in collaboration with American Radio Works.

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