Reengineering The Mississippi

摘要

Governments at both the state and federal level, led by the engineering community, are awakening to one of the greatest threats to our nation's economy and its environment: the Mississippi River Delta, so emblematic of life in coastal Louisiana, is also the outlet that drains the rivers flowing through Americas heartland. As a major commerce center in its own right, the delta is of fundamental importance to the nation's economy—and it is in serious trouble. The summary report from the Coastal Louisiana Technical Summit, which was organized by ASCE at the request of the State of Louisiana's America's WETLAND public information initiative and took place October 16-17 last year in New Orleans, describes the problem in this way: Coastal Louisiana is one of the world's most significant wetland areas. It has lost over 900,000 acres [365,000 ha] since the 1930s. As recently as the 1970s, the loss rate for Louisiana's coastal wetlands was as high as 25,600 acres [10,400 ha] per year. The current rate of loss is about 16,000 acres [6,500 ha] per year. It is estimated that coastal Louisiana will experience a[n additional] 320,000 acre [130,000 ha] net loss by the year 2050. Although the problem has been developing for decades, neither the state nor the federal government has been able to develop and build projects of the scope that would make a difference. However, with coastal land disappearing at the rate of 2 acres (0.8 ha) an hour, the scope and urgency of the engineering challenge become clearer every day. A century of engineering in the Mississippi basin to prevent floods and aid navigation has created the present situation. Only reengineering the Mississippi can restore a balance that will stop the land loss and enable coastal Louisiana to become stable and self-sustaining.