Nominee Projects Located in Region One
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Nominee Projects located in Region One Irish Bayou Shoreline Protection and Marsh Creation Project PPL17 PROJECT NOMINEE FACT SHEET February 22, 2007 Project Name: Irish Bayou Wetland Creation and Shoreline Protection Coast 2050 Strategy: Region 1 Ecosystem Strategy Nos. 9, 10, and 13: Dedicated delivery of sediment for marsh building, maintaining shoreline integrity of Lake Pontchartrain, and maintaining eastern Orleans Land Bridge by marsh creation and shoreline protection. Project Location: Region 2, Pontchatrain Basin, Orleans Parish, South of I-10, on Bayou Sauvage NWR, with borrow area in Lake Pontchartrain. Problem: The landfall of Hurricane Katrina in southeast Louisiana destroyed thousands of acres of marsh and other coastal habitats in the Lake Pontchartrain basin. The hurricane weakened the Lake Pontchartrain shore between the lake rim and interior marshes near Bayou Chevee. In some cases the storm removed large expanses of the shoreline and exposed interior marshes. Currently only a portion of the lakeshore is protected by a rock dike (PPL 5, PO-22). This dike was originally tied to the shoreline; however the interior marsh has eroded away. Continued shoreline erosion and future storms could create a direct path of open water connecting Lake Pontchatrain with Irish Bayou and the Bayou Sauvage NWR. Goals: Create 135 acres of marsh and provide shoreline protection to about 26,876 feet of the Bayou Sauvage NWR. The project would maintain the shoreline integrity of Lake Pontchartrain and reduce the threat of Lake Pontchartrain merging with Irish Bayou and the Bayou Sauvage Refuge. The project would also help to buffer and protect the stability of the existing federal hurricane protection levee in New Orleans East. The project would also help to provide wildlife and fisheries habitats and water quality benefits, and the restored marsh vegetation would buffer/weaken storm surge in New Orleans East. Proposed Solutions: • Dedicated dredging to restore wetlands along the weakened shoreline and current rock dike. o Assuming an average 3ft fill/site o Part of B is located behind an existing stone dike o Site A will be confined with a retaining dike o Site B will be semi-confined and allowed to flow into the adjacent marsh of Bayou Sauvage. Marsh Approximate Estimated Material Creation Acres Created Required (cy) Site A 53 340,000 B 82 520,000 Total 135 860,000 • Extending the existing rock dike along the reach mouth of Chef Menteur Pass to the base of the railroad trestles. Estimated Length Construction Reach tons/lf Rock Required (lf) elevation (NAVD88) (tons) 1 9,708 +3.0 ft 4 tons/lf 38,800 2 5,315 +3.0 ft 4 tons/lf 21,300 3 7,000 +3.0 ft 4 tons/lf 28,000 4 4,853 +3.0 ft 4 tons/lf 19,400 Total 26,876 107,500 Preliminary Project Benefits: 1. What is the total acreage benefited both directly and indirectly? The project would directly create approximately 135 acres of marsh and protect 165 acres. Indirectly, an additional 905 acres of interior marsh and lake rim would benefit by establishing an intact barrier from Lake Pontchartrain. 2. How many acres of wetlands will be protected/created over the project life? 294 net acres would be protected/created over the project life. 3. What is the anticipated loss rate reduction throughout the area of direct benefits over the project life (<25%, 25-49%, 50-74% and >75%). Loss rate reduction overall >75% 4. Do any project features maintain or restore structural components of the coastal ecosystem such as barrier islands, natural or artificial levee ridges, beach and lake rims, cheniers, etc. The project would restore/protect a lake shoreline and preserve portions of the critical East Orleans Landbridge. 5. What is the net impact of the project on critical and non-critical infrastructure? The project will also provide protection to critical infrastructure in New Orleans east including the hurricane protection levee and the nearby I-10 corridor. 6. To what extent does the project provide a synergistic effect with other approved and/or constructed restoration projects? The project provides some synergy with other projects protecting the East Orleans Landbridge and nearby mapping units including projects at Bayou Chevee (PO-22), and on the Bayou Sauvage NWR. Identification of Potential Issues: • Rock shoreline protection projects historically require O&M. • Area is in the vicinity of critical habitat for Gulf Sturgeon. Preliminary Construction Costs: Estimated construction cost with 25% contingency: approximately $13.8 Million. Estimated Fully Funded cost approximately: $26.1 Million Preparer(s) of Fact Sheet: Melanie Goodman, USACE, (504) 862-1940, [email protected] Travis Creel, USACE, (504) 862-1071, [email protected] Jason Binet, USACE, (504) 862- 2127, [email protected] Robert T. Dubois, USFWS, 337-291-3127, [email protected] Project Map: Orleans Landbridge Marsh Creation and Shoreline Protection Project PPL17 PROJECT NOMINEE FACT SHEET March 5, 2007 Project Name: Orleans Landbridge Marsh Creation and Shoreline Protection Coast 2050 Strategy: Coastwide: Maintain bay and lake shoreline integrity. Regional 10: Maintain shoreline integrity of Lake Pontchartrain. Regional 13: Maintain Eastern Orleans Land Bridge by marsh creation and shoreline protection. Mapping Unit 36: Maintain shoreline integrity Project Location: Region 1, Pontchartrain Basin, Orleans Parish, East Orleans Landbridge Mapping Unit, along south shore of Lake Ponchartrain near Chef Pass and the Rigolets. Problem: High wave energy, sea level rise and subsidence levels are impacting the wetland shorelines of Lake Pontchartrain, Chef Pass, and the Rigolets. Shorelines in the area are exhibiting increasingly high erosion rates dating since the 1980s and were highly impacted during Hurricane Katrina. Identified in both Coast 2050 and the LCA, this critical landbridge forms a barrier between Lake Pontchartrain and Lake Borgne, an eventual passage to the Gulf of Mexico. This thin land mass of mostly brackish marsh was home to over 1,000 residents prior to the storm and protects an inland population of approximately 850,000 people in the city of New Orleans and Metairie along with billions of dollars of infrastructure and historic communities. The disappearance of shoreline and marsh in this area endangers this narrow landbridge that keeps Lake Pontchartrain from joining Lake Catherine and Lake Borgne. Continued erosion without action will result in the acceleration of the loss of the remaining marsh tidal marshes in the area. Goals: • Maintain the East Orleans Landbridge by stopping shoreline erosion. • Protect recovering communities and infrastructure located on the landbridge and inland. • Contribute to the “multiple lines of defense” coastal protection and restoration strategy Proposed Project Features: • Dedicated dredging to restore wetlands along the weakened shoreline. o Assuming an average 4ft fill/site for Area A and 3ft fill/site for Area B. o Both sites will be semi-confined and allowed to flow into the adjacent marsh. Marsh Approximate Estimated Material Creation Acres Created Required (cy) Site A 26 221,000 B 52 338,000 Total 78 559,000 • Rock dike on Lake Pontchartrain east of Chef Pass and west of The Rigolets at Hospital Wall. Construction Estimated Length Reach elevation tons/lf Rock Required (lf) (NAVD88) (tons) North Reach 12,150 +3.0 ft 4 tons/lf 50,000 South Reach 9,250 +3.0 ft 4tons/lf 37,000 Total 21,400 87,000 Preliminary Project Benefits: 1. What is the total acreage benefited both directly and indirectly? The project would directly create approximately 78 acres of marsh and protect 88 acres. Indirectly, an additional 780 acres of interior marsh and lake rim would benefit by establishing an intact barrier from Lake Pontchartrain. 2. How many acres of wetlands will be protected/created over the project life? 156 net acres would be protected/created over the project life. 3. What is the anticipated loss rate reduction throughout the area of direct benefits over the project life (<25%, 25-49%, 50-74% and >75%). Loss rate reduction overall >75% 4. Do any project features maintain or restore structural components of the coastal ecosystem such as barrier islands, natural or artificial levee ridges, beach and lake rims, cheniers, etc. The project would restore/protect a lake shoreline and preserve portions of the critical East Orleans Landbridge. 5. What is the net impact of the project on critical and non-critical infrastructure? The project will also provide protection to critical infrastructure in New Orleans east including the hurricane protection levee and the nearby I-10 corridor. 6. To what extent does the project provide a synergistic effect with other approved and/or constructed restoration projects? The project provides some synergy with other projects protecting the East Orleans Landbridge and nearby mapping units including projects at Bayou Chevee (PO-22), and on the Bayou Sauvage NWR. Identification of Potential Issues: • Rock shoreline protection projects historically require O&M. • Area is in the vicinity of critical habitat for Gulf Sturgeon. Preliminary Construction Costs: Estimated construction cost with 25% contingency: approximately $10.6 Million. Estimated Fully Funded cost approximately: $20.4 Million Preparers of Fact Sheet: Mr. Leo Richardson, Lake Catherine Civic Association, [email protected] Mr. John Lopez, Lake Pontchartrain Basin Foundation, [email protected] Travis Creel, U.S. Army Corp of Engineers, [email protected]