1. ERDC Knowledge Core
2. United States Army Corps of Engineers (USACE)
3. Mississippi Valley Division
4. New Orleans District
5. Environmental Documents

Title:	Final Post Authorization Change Report and Revised Programmatic Environmental Impact Statement: Morganza to the Gulf of Mexico, Louisiana
Authors:	United States. Army. Corps of Engineers. New Orleans District. Louisiana. Coastal Protection and Restoration Authority. Terrebonne Levee & Conservation District.
Keywords:	Flood control Spillways Mississippi River Morganza (La.) Environmental management
Publisher:	United States. Army. Corps of Engineers. New Orleans District.
Abstract:	The U.S. Army Corps of Engineers – Mississippi Valley Division, New Orleans District proposes to make changes and improvements in the planning, design, construction, operation, and maintenance of the Morganza to the Gulf hurricane and storm damage risk reduction system project to prevent future disasters to the greatest extent possible. The purpose of this project is to reduce the risk of damage caused by hurricane storm surges. The project is needed because of the increasing susceptibility of coastal communities to storm surge due to wetland loss, sea level rise, and subsidence. The project is located approximately 60 miles southwest of New Orleans, Louisiana, and includes most of Terrebonne Parish and the portion of Lafourche Parish between the Terrebonne Parish eastern boundary and Bayou Lafourche. Alternatives investigated are a 1% Annual Exceedance Probability Storm Surge Risk Reduction System, which would provide risk reduction for water levels that have a 1 percent chance of occurring each year, and a 3% AEP Storm Surge Risk Reduction System, which would provide risk reduction for water levels that have a 3 percent chance of occurring each year. A sponsor-funded additional work item, which would involve deepening the Houma Navigation Canal Lock Complex to -23 feet NAVD88, is an option that could be incorporated into either the 1% or 3% AEP alternatives. The two action alternatives include programmatic elements that would be further investigated in the future and constructible elements for which this Revised Programmatic Environmental Impact Statement would serve as the required documentation under the National Environmental Policy Act. The 1% AEP alternative has been identified the plan with the greatest net benefits of the two alternatives. The major direct impact of the project is the loss of wetlands within the project right of way. There is a potential for adverse indirect and cumulative impacts to wetlands, fisheries, water quality, and navigation due to increased frequency and duration of water control structure closures in the future compared to without project conditions. The potential impacts that would be attributable to the proposed operation of the Federal levees system are unknown at this time but under some scenarios, these impacts could be significant. The level of impact would be dependent on the resource looked at, how the operating plan is changed, the amount of background wetland loss due to relative sea level rise, modifications in the systems to provided navigation access, and/or any changes resulting from the project being constructed and operated by the State of Louisiana and Terrebonne Levee and Conservation District along the alignment of the proposed Federal project. Mitigation for wetland impacts would be through the restoration of eroded and subsided wetlands in the project area. The project would complement state and Federal coastal restoration projects in the area by reducing the risk of coastal erosion due to storm surges.
Description:	Environmental Impact Statement
URI:	https://hdl.handle.net/11681/34859
Appears in Collections:	Environmental Documents