South Central Coast Louisiana Supplemental Final Integrated Feasibility Study with

Environmental Impact Statement

St. Mary, Iberia, and St. Martin Parishes, Louisiana

The Supplemental Final Integrated Feasibility Report and Environmental Impact Statement (IFR/EIS) dated May 2022 for the South Central Coast Louisiana Supplemental Final Integrated Feasibility Report with Environmental Impact Statement addresses coastal storm risk management opportunities and feasibility in the. St.

Martin, Iberia, and St. Mary Parishes, Louisiana. The final recommendation is contained in the report of the Chief of Engineers, dated June 23, 2022. Based on these reports, the reviews by other Federal, State, and local agencies, Tribes, input of the public, and the review by my staff, I find the plan recommended by the Chief of Engineers to be technically feasible, economically justified, in accordance with environmental statutes, and the public interest.

The Supplemental Final IFR/EIS, incorporated herein by reference, evaluated various alternatives that would reduce flood risk in the study area. The recommended plan is the National Economic Development Plan and includes:

In addition to a “no action” plan, the U.S. Army Corps of Engineers (Corps) evaluated one other acceptable alternative. Alternative 2 includes floodproofing or elevation of 5,035 structures located within the 50-year Floodplain to the 0.01 Annual Exceedance Probability future storm surge elevation. The IFR/EIS Section 3 includes a full discussion of the alternative formulation and screening process. Alternative 2 differs from Alternative 1 in its floodplain extent: Alternative 1 evaluates the study area’s flood risk in the 25-year floodplain and Alternative 2 evaluates the flood risk in the 50-year

flood floodplain. The IFR/EIS Section 3 includes a full discussion of the alternative formulation and screening process. Both alternatives are non-structural.

The Corps identified Alternative 1 as the environmentally preferable alternative.


For all alternatives, the potential effects were evaluated, as appropriate. A summary assessment of the potential effects of the recommended plan is listed in Table 1:

Table 1: Summary of Potential Effects of Recommend Plan

Significant adverse effect*

Insignificant effects due to mitigation**

Insignificant effects

Resource unaffected by action


Air quality

Aquatic resources/wetlands

Invasive species

Fish and wildlife habitat

Threatened/Endangered species

Historic properties

Other cultural resources


Hazardous, toxic & radioactive waste


Land use


Noise levels

Public infrastructure


Environmental justice


Tribal trust resources

Water quality

Greenhouse gas emissions and Climate change

Relative sea level rise

Essential fish habitat

Marine Mammals


Coastal zone resources and uses

The Corps analyzed all practicable means to avoid or minimize adverse environmental effects and incorporated them into the recommended plan.

No compensatory mitigation is required as part of the recommended plan.

Public review of the initial draft IFR/EIS was completed on January 6, 2020. All comments submitted during the public comment period were responded to in the initial Final IFR/EIS. The 30-day state and agency review and waiting period of the initial Final IFR/EIS were completed on August 23, 2021, and October 4, 2021, respectively. The Corps posted a supplemental draft IFR/EIS for a 30-day public comment period ending on May 2, 2022. The Corps conducted a concurrent state and agency review and public review for the Supplemental Final IFR/EIS ending on August 17, 2022. No additional comments were received during the final two reviews.

Pursuant to section 7 of the Endangered Species Act of 1973, as amended, the Corps determined the recommended plan will have no effect on federally listed species or their designated critical habitat.

Pursuant to section 106 of the National Historic Preservation Act of 1966, as amended, the Corps determined historic properties may be adversely affected by the recommended plan. The Corps and the Louisiana Coastal Protection and Restoration Authority; Louisiana State Historic Preservation Officer of The Department of Culture, Recreation & Tourism; Chitimacha Tribe of Louisiana; and Mississippi Band of Choctaw Indians entered into a programmatic agreement, dated November 16, 2020. The Corps concluded a phased process to conduct identification and evaluation of historic properties and for application of the criteria of Adverse Effect, including the resolution of Adverse Effects, is an appropriate and necessary approach for the agency to meet the requirements of Section 106.

The recommended plan will not impact any waters of the United States and therefore the US Army Corps of Engineers is not required to complete a Clean Water Act 404(b)(1) Evaluation in accordance with the Clean Water Act, Section 404(b)(1) Guidelines, pursuant to the Clean Water Act of 1972, as amended.

The recommended plan will not impact any waters of the United States and therefore the US Corps is not required to obtain a Clean Water Act, Section 401 water quality certification from the State of Louisiana.

A determination of consistency with the Louisiana Coastal Zone Management program pursuant to the Coastal Zone Management Act of 1972 will be obtained from the Louisiana Department of Natural Resources (LDNR) prior to construction. In a letter dated October 14, 2020, the LDNR stated the recommended plan appears to be consistent with state Coastal Zone Management plans, pending confirmation based on information to be developed during the pre-construction engineering and design phase. All conditions of the consistency determination shall be implemented in order to minimize adverse impacts to the coastal zone.

The voluntary nonstructural plan described in the IFR/EIS will not disproportionally impact EJ communities. Potential impacts are not disproportionately high and adverse.

All structures within the 25-year flood zone are located in economically justified reaches and would be voluntarily flood-proofed or elevated; therefore, all residents within the reaches, irrespective of race, ethnicity, or income, would be able to choose to participate in the plan. The Corps considered and coordinated all other applicable environmental laws with appropriate agencies and officials.

Technical, environmental, economic, and cost effectiveness criteria used in the formulation of alternative plans were those specified in the Water Resources Council’s 1983 Economic and Environmental Principles and Guidelines for Water and Related Land Resources Implementation Studies. All applicable laws, executive orders, regulations, and local government plans were considered in evaluation of alternatives. Based on the review of these evaluations, I find the benefits of the recommended plan outweigh the costs and any adverse effects and certify the Corps considered all the alternatives, information and analyses submitted by public commenters based on the summary in the supplemental final EIS. This Record of Decision completes the National Environmental Policy Act process.

August 4, 2023

Date Michael L. Connor

Assistant Secretary of the Army (Civil Works)