Grand Isle and Vicinity

Study Authority

Resolutions adopted September 26, 1963, and May 5, 1966, by the Committee on Public Works of the House of Representatives, United States authorized the original Grand Isle and Vicinity, Louisiana Study; Section 216 of the Flood Control Act of 1970 and Division B, Title IV of the Disaster Relief Supplemental Appropriations Act, 2022, Public Law 117-43, enacted September 30, 2021 authorize the Grand Isle and Vicinity, Louisiana General Re-evaluation Study.

Additional authorizations:  Section 204 of the Flood Control Act of 1965 (79 STAT 1077) (PL 89-298) substantially in accordance with the recommendation of the Chief of Engineers in House Document 84, 89th Congress.  Section 301(b)(6) of the Water Resources Development Act of 1996 (PL 104-303) (110 STAT 3710), modified original project authorized by Section 204 of the Flood Control Act of 1965 (79 STAT 1077) to authorize the construction of a permanent levee and breakwater system. The Bipartisan Budget Act of 2018 (Public Law 115-123), Division 8, funding to construct breakwaters and provide for shoreline erosion protection authorized pursuant to WRDA 1996.


Study Purpose

Grand Isle has been subjected to repeated damages to the sand dune and beach berm on the southern Gulf side of the island due to increased frequency storm events and associated high wave energy resulting in erosion.  The sand dune and beach berm are the island's main defense against wave energy directly impacting the island’s residential and commercial structures.  The goal of the study is to develop and evaluate alternatives to reduce flood risk for the Town of Grand Isle as well as reduce the risk of storm damage to existing flood risk reduction features. 


Study Area

The study area encompasses all the island Grand Isle located on the Gulf of Mexico in Lower Jefferson Parish, Louisiana, about 50 miles south of New Orleans and 45 miles northwest of Southwest Pass of the Mississippi River. Grand Isle is the westernmost of the barrier islands lying across the mouth of Barataria Bay. The island extends about 7.5 miles in a generally northeast to southwest direction and is about 0.75 miles in width at the center.


Local Sponsor

The Coastal Protection and Restoration Authority Board of Louisiana is the non-federal sponsor. This study is 100 percent Federally funded.



For Questions about the Study