Background on Lower Mississippi River Basin

The Lower Mississippi River Basin (Mississippi Alluvial Valley) extends 954 river miles from the confluence of the Ohio and Mississippi rivers at Cairo, Illinois to the Gulf of Mexico. The Mississippi Alluvial Valley covers a portion of six states: Mississippi, Tennessee, Kentucky, Missouri, Arkansas and Louisiana. The area consists of over 115 counties. Approximately 2.7 million people live within the Mississippi Alluvial Valley. The alluvial valley ranges from 30 to 110 miles wide and encompasses approximately 22 million acres. At least 91 species of freshwater fish are found in the valley. Nearly 40% of North America's waterfowl and 60% of all bird species in the United States migrate through the valley.

Lake Pontchartrain and adjacent lakes in Louisiana form one of the larger estuaries in the Gulf Coast region. The estuary drains the Pontchartrain Basin (at right), an area of over 12,000 km2 situated on the eastern side of the Mississippi River delta plain. In Louisiana, nearly one-third of the State population lives within the 14 parishes of the basin.

Agricultural lands dominate the landscape with almost 40% of the coverage. Wetlands comprise 28% of the total surface area. Agriculture, silviculture, aquaculture and commercial fisheries at the coastal wetlands are the major land uses.

During the 1900's flood control efforts straightened and deepened rivers, drained swamps, and encouraged forest clearing on lower, wetter sites. Between 1950 and 1976, approximately one-third of the Valley's bottomland forests were converted to agriculture. By the 1980's less than 20% of the original forested wetlands were left. While the loss of the forests was devastating to this ecosystem, equally damaging were the effects of flood control projects (i.e. levees and channelization) that separated the rivers from the floodplains. Deforestation and draining of wetland areas resulted in a loss of critical wildlife and fish habitat, decreased water quality, reduced flood water retention, and increased sediment loads, all of which have contributed to an expansion of the hypoxic zone in the Gulf of Mexico.

In addition, Louisiana is experiencing the Nation's highest rate of coastal land loss, placing human lives at risk as well as billions of dollars of infrastructure. Within the last 50 years, land loss rates have exceeded 40 square miles per year, and in the 1990s the rate has been estimated to be between 25 and 35 square miles each year. This land loss represents 80% of the coastal wetland loss in the entire continental United States.

The region's abundant rainfall, finely textured alluvial soils and intensive cultivation have contributed to serious non-point source pollution problems. An estimated 12-45 tons of soil per acre are lost from agricultural lands in the LMAV each year leading to increased water turbidity, siltation, pollution from pesticide and herbicide run-off, toxicity to fish and other aquatic organisms, oxygen depletion and eutrophication. High pathogen loads have led to the closure of many of the shellfish grounds at the coast.

Along with the loss of acreage goes the loss of the various functions and values associated with the wetlands: commercial harvests of fisheries, furbearers and alligators; recreational fishing and hunting, and ecotourism; habitats for threatened and endangered species; water quality improvement; navigation corridors and port facilities; and flood control, including buffering hurricane storm surges.

According to U.S. Census data from 1990-1999 approximately 2.7 million people live within the over 115 counties covered by the Mississippi Alluvial Valley. Many counties have lost population over the past decade. Overall, the average poverty rate for all counties within the Mississippi Alluvial Valley was 21.2% (1.7 times the national average). The average per capita income was only 67% of the United States average for 1998.