West Shore Levee design changes examined in Supplemental Environmental Assessment

Published 2:18 pm Friday, June 2, 2023

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The U.S. Army Corps of Engineers, New Orleans District, have released a draft Supplemental Environmental Assessment (SEA 571) and a draft Finding of No Significant Impact (FONSI) for the West Shore Lake Pontchartrain (WSLP) Hurricane and Storm Damage Risk Reduction system in St. Charles and St. John the Baptist Parishes. The drafts will be available for public review and comment from June 2, 2023 until July 3, 2023. A copy of the SEA is available upon request or can be downloaded from: https://www.mvn.usace.army.mil/About/Projects/BBA-2018/West-Shore-Lake-Pontchartrain/.

The draft SEA 571A evaluates the potential impacts of altering the levee alignment footprint as described in the West Shore Lake Pontchartrain Environmental Impact Statement (2016 WSLP EIS) and SEA 571, and modifications to features described in SEA 570 and SEA 571. The majority of changes would be within the SEA 571 construction ROW corridor, except for temporary bypass roads to be constructed near the I-55 pump station and drainage structures; temporary construction activities near the Prescott Canal Drainage structure; construction of a power transmission corridor for the Reserve Relief Pump Station; and a levee system re-alignment to accommodate a proposed runway extension for the Port of South Louisiana’s Executive Regional Airport in Reserve, Louisiana.

Design changes within the SEA 571 construction ROW include alteration of levee system and drainage canal designs and locations; drainage structure design, size and locations; and pump station design, number and locations. Approximately 201 less acres of direct, negative impacts to swamp habitat (net of approximately 104 more AAHUs of swamp), and 18 less acres of direct, negative impacts to BLH habitats (net of approximately 13 more AAHUs of BLH) would be impacted as compared to SEA 571. Indirect impacts to wetlands were found to be similar to those described in SEA 571, except for approximately 245 acres near I-55 where there would be additional hydrologic impacts beyond what was assessed in SEA 571.

The West Shore Lake Pontchartrain project will achieve 100-year storm surge risk reduction by a variety of structural and non-structural features to include: levees, floodwalls, and pumps. While these features will reduce risk from storm surge associated with tropical events, they do not specifically reduce risk of flooding from significant rainfall. The project design team continues to work with the Non-Federal sponsor to acquire Rights of Entry (ROE) and coordinate with utilities and pipelines within the project footprint. Contracts completed include test sections, clay stockpiles, sand stockpiles, sand placement, and access road construction. For more information on the West Shore Lake Pontchartrain project: