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Morganza to the Gulf of Mexico Risk Reduction Project |
Official Project Name
Morganza to the Gulf of Mexico Risk Reduction Project
(Visit stakeholder site here: http://www.mvn.usace.army.mil/prj/mtog/ )
Location
The proposed work is located in coastal Louisiana approximately 60 miles southwest of New Orleans and includes portions of Terrebonne and Lafourche Parishes. The area is bounded on the west by Bayou Du Large and State Highway 311 and on the east by Bayou Lafourche with the east and west boundaries forming an apex at Thibodaux, LA. The southern boundary is the Gulf of Mexico.
Purpose
This project aims to protect people and property as well as the remaining fragile marsh from hurricane storm surge in the vicinity of Houma, Louisiana. The area has been affected by an extreme deterioration of coastal marshes as a result of saltwater intrusion, land subsidence and the lack of sediment deposits from the Mississippi River and its tributaries. This deterioration has led to increased hurricane and storm surge inundation. The area is also significantly affected by tides emanating from the Gulf of Mexico.
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Status
All the prerequisites for receiving Congressional authorization for this project were completed by 2002. Subsequently, concerns arose regarding the size of the canal lock. The issue was revisited by stakeholders, and the result was a new design to accommodate the movement through the locks of large oil rigs constructed by Houma fabricators. By 2003, the project was again ready to receive authorization and funding so construction could begin.All the prerequisites for receiving Congressional authorization for this project were completed by 2002. Subsequently, concerns arose regarding the size of the canal lock. The issue was revisited by stakeholders, and the result was a new design to accommodate the movement through the locks of large oil rigs constructed by Houma fabricators. By 2003, the project was again ready to receive authorization and funding so construction could begin.
Federal projects aimed at managing the nation’s water resources typically receive congressional authorization through the Water Resources Development Act (WRDA). Historically, Congress has considered WRDA legislation approximately every other year. After the 2000 WRDA bill, however, Congress did not pass any new WRDA legislation until 2007. Thus, the Morganza to the Gulf Hurricane Protection project was not authorized until 2007.
In the interim, Hurricanes Katrina and Rita devastated the Gulf Coast. Congress responded by passing a series of emergency supplemental appropriations bills to fund short-term repairs and long-term enhancements of the hurricane protection system in south Louisiana. Funding was provided only for previously authorized projects. The Morganza project, though an integral part of the Hurricane and Storm Damage Risk Reduction System (HSDRRS), did not receive emergency funding because it had not yet been authorized when the funding bills passed.
Post-Katrina hurricane protection projects are being planned and built according to new design criteria to provide a stronger, more robust system of protection than existed before Katrina. As this project was planned five years before Katrina, its design does not meet the Corps’ new standards for 100-year level protection. The project’s design must now be revised and will likely result in a substantially higher cost, increased direct and indirect impacts, and the need to complete a report for Congress explaining these changes.
Features under Construction:
Levee Reach J-1, First Lift, 95% complete (Work-in-Kind);
Levee Reach, H-3, First Lift, 0% complete (awarded DEC 2008) (WIK)
Features under Design:
Levee Reach J-2, First Lift, 35% P&S (WIK);
Pointe Aux Chenes Levee, First Lift, 50% P&S (WIK);
Houma Navigation Canal (HNC) Lock and Floodgate Complex, 50% P&S complete July 2008;
Levee Reach F-1, 25% DDR;
Levee Reach G-1, 35% DDR;
Bayou Grand Caillou Floodgate, 35% DDR
Post Authorization Change (PAC) Report:
The Congressionally-mandated Section 902 Limit (WRDA 1986) requires reauthorization by Congress when construction costs are estimated to exceed the authorized project cost by a 20% increase. Due to Post-Katrina design criteria changes, including new 100-year elevations, and new borrow standards, Morganza to the Gulf will clearly exceed this 20% cost increase limit. The Morganza to the Gulf project will need reauthorization from Congress to start construction. A PAC report is being developed that will serve as the basis for reauthorization. The PAC report will include detailed designs incorporating the post-Karina design criteria, new project costs and updated economic benefits.
Benefit to the Community & Project Features
Benefit to the Community
There is currently no federal hurricane protection in place in this region. This project affects the safety of more than 150,000 people and 1,700 square miles of farmlands, and industrial and residential areas.
Features
The project’s structural features are integrated into the levee alignment in a way that would provide flood protection, drainage, environmental benefits, and navigational passage. The plan includes mitigation efforts for direct environmental impacts, namely creating 1,352 acres of new marsh.
The recommended hurricane protection plan consists of:
• approximately 72-miles of earthen levee,
• ten 56-foot-wide sector gate structures,
• three 125-foot wide sector gate structures,
• 13-tidal exchange structures, and
• a lock complex consisting of a lock in the Houma Navigation Canal measuring 110-ft wide by 800-ft long, an adjoining floodgate measuring 250 feet wide, and a dam closure.
Authority
Water Resources Development Act of 2007
Scope
Approximately 72-miles of earthen levee, nine 56-foot sector gate structures, three 125-foot floodgates, 13-floodgate structures, 13-tidal exchange structures and a lock complex consisting of a lock in the Houma Navigation Canal measuring 110-feet by 800-feet, an adjoining floodgate measuring 250 feet, and a dam closure. The structural features are integrated into the levee alignment to provide flood protection, drainage, environmental benefits, and navigational passage. Construction would be cost shared 65% / 35% with LADOTD, the local sponsor.
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