Drawing Louisiana's New Map Addressing Land Loss in Coastal Louisiana (2006) / Chapter Skim
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1 Introduction
1 Introduction
Pages 13-28
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From page 13... ...
, Louisiana -- Ecosystem Resto ration Study (LCA Study) · Summarizes the challenges to curbing losses and the need for understanding natural processes · Outlines the structure of this report On August 29, 2005, Hurricane Katrina struck eastern Louisiana, Mississippi, and western Alabama, killing hundreds of local residents, displacing hundreds of thousands more, and causing an estimated $200 billion in economic damage.
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From page 14... ...
When the late Wisconsian glaciers began melting 4,000 years later, an era of sea level rise known as the Holocene transgression began, and with it came dramatic changes in the basin's hydrologic character. As the Mississippi River Basin eroded, the Mississippi River changed from a system of braided streams carrying coarse-grained sediments to a sinuous, meandering, interconnected system that carried relatively fine grain clay, silt, and sand, similar in some respects to that known today.
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From page 15... ...
As a consequence, the seaward portions of the Mississippi River Delta that make up coastal Louisiana, including New Orleans, naturally experience much higher subsidence rates than the vast majority of the North American continent. Until humans began to alter the flow of river water and the sediment it carried, the natural system was, on average, able to keep pace with natural subsidence and global sea level rise.
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From page 16... ...
has also contributed to wetland loss in many areas. Natural causes of land loss include subsidence due to compaction of aging deltaic sediments, geologic faulting, sea level rise, and tropical storms or hurricanes.
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On the scale of centuries, this would allow new areas to stabilize and become colonized by vegetation and animals. The abandoned delta lobe would gradually be lost at a rate that would depend on relative sea level rise and storm intensity.
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Coastal Wetlands Planning, Protection, and Restoration Act Initial efforts to offset catastrophic land loss have been implemented under CWPPRA, which called for the development of a comprehensive Louisiana Coastal Wetlands Restoration Plan (P.L.
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1980 -- Coastal management efforts in Louisiana led to the Louisiana Coastal Resources Program, which became a federally approved coastal zone management program. 1981 -- Act 41 of the Louisiana Legislature special session established the Coastal Environment Protection Trust Fund and appropriated $35 million for projects to combat erosion, saltwater intrusion, subsidence, and wet land loss along Louisiana's coast.
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From page 20... ...
2003 -- Louisiana Coastal Area, LA -- Ecosystem Restoration: Comprehen sive Coastwide Ecosystem Restoration Study (draft LCA Comprehensive Study) was released in draft form by USACE and the Louisiana Department of Natural Resources as a possible comprehensive, long-term restoration plan.
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From page 21... ...
to maintain an estuarine salinity gradient to achieve diversity, and (3) to maintain exchange and interface to achieve system linkages (Louisiana Coastal Wetlands Conservation and Restoration Task Force and the Wetlands Conservation and Restoration Authority, 1998)
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The draft LCA Comprehensive Study was the next step in the development of an implementation plan for Coast 2050. The goal of the draft LCA Comprehensive Study was to provide a "comprehensive program to reestablish a sustainable ecosystem along Louisiana's coast that will support and protect the environment, economy, and culture of southern Louisiana" (U.S.
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Borrowing from the plans and strategies developed in Coast 2050 and the draft LCA Comprehensive Study, the project development team narrowed the selection of near-term restoration projects to those "that can be implemented within the next 510 years, demonstration projects to resolve scientific and engineering uncertainty, and large-scale studies of long-range feature concepts" (U.S. Army Corps of Engineers, 2004a)
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From page 24... ...
The broad goal of Coast 2050 -- "to sustain a coastal ecosystem that supports and protects the environment, economy, and culture of southern Louisiana, and that contributes greatly to the economy and well-being of the nation" (Louisiana Coastal Wetlands Conservation and Restoration Task Force and the Wetlands Conservation and Restoration Authority, 1998) -- has been developed into a narrower, overarching LCA Study objective "to reverse the current trend of degradation of the coastal ecosystem" (U.S.
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From page 25... ...
This level of public participation is far lower than that seen for either the development of Coast 2050 or the draft LCA Comprehensive Study, in part reflecting the abbreviated time during which the LCA Study was developed. ORIGIN AND SCOPE OF THE CURRENT STUDY In an effort to secure additional outside technical input, the State of Louisiana and USACE initially requested that the National Academies undertake a review of the objectives envisioned and the actions proposed in Coast 2050.
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From page 26... ...
· Does the phased approach outlined in the LCA Study provide an adequate basis to start developing a comprehensive coastal restoration plan to achieve the broad goals articulated by Coast 2050: Toward a Sustain able Coastal Louisiana? framed by the statement of task, the committee had to understand the challenges facing existing efforts to restore and protect coastal Louisiana as well as efforts proposed in the LCA Study.
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From page 27... ...
This essentially rules out a natural approach to maintaining land areas in such locations and leaves constructed levees around the developments as the most probable future approach for flood protection. Another example is that the municipal and industrial water supply for New Orleans is obtained from the Mississippi River.
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From page 28... ...
An example is that at one time the Mississippi River with its natural levees ended at the current Head of Passes. Were all of these past landscapes less desirable than the one that these efforts are designed to preserve?
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