Restoration-Quality Sand from Ship Shoal, Louisiana: Geotechnical Investigation for Sand on a Drowned Barrier Island

In an effort to more accurately evaluate sand volumes that are potentially available for coastal restoration, high-resolution geophysical data were collected followed by detailed geotechnical investigations in two study areas in Ship Shoal Complex. Interpretation of vibracores helped to identify about 13.2 x 10⁶ m³ of clean sand (<5 % silt: D₅₀ ~0.20 mm) in portions of Ship Shoal Blocks 88 & 89. Geotechnical exploration of South Pelto Blocks 12 & 13 also identified mostly clean sand (D₅₀ grain size 0.15 to 0.2 mm) with less than 5% silt in upper stratigraphic units 4 to 6 m thick. Combined volumes of three closely spaced potential borrows amounted to approximately 21.6 x 10⁶ m³. Comparison of sediments on emergent barrier islands with those on the drowned barrier known as Ship Shoal indicates a high level of compatibility for restorative work on Isle Dernieres and Lafourche delta coastal segments.