Lake Lery Marsh Creation & Rim Restoration (Phase 3)

The Beta Group provided geotechnical engineering for the Lake Lery Marsh Creation and Rim Restoration Phase III Project.

Phase III consists of the creation of 177 acres of marsh and the nourishment of an additional 209 acres from near the edge of the embankment to approximately 1,500 ft. behind the existing shoreline located along the northwestern shoreline in/near Lake Lery in St. Bernard Parish, Louisiana. Preliminary footprints for marsh creation, marsh nourishment and lake rim restoration have been delineated but are subject to change during engineering and design. Phase III includes the dredging of material from Lake Lery and pumping the material into contained marsh creation cells along the northwest reach of the Lake Lery shoreline. The shoreline embankment, required to prevent damage to the proposed marsh creation cell, runs parallel 2.42 miles from the Plaquemines Parish and St. Bernard Parish boundary, terminating at the intersection of the remaining Eighty Arpent Canal southern bank. The embankment will also include a wide crown and gentle embankment slope, which will include smooth cordgrass and bullwhip plantings.

TBG drilled a total of twenty-nine (29) undisturbed soil borings for the project. Nine (9) undisturbed soil borings were drilled to the 60 ft. depth below the mud-line in the general alignment of the earthen containment dike (one (1) boring for every 1,500 linear feet), eight (8) undisturbed soil borings were drilled to the 40 ft. depth below the mud-line in the general area of the 209-acres of Marsh Creation and 177-acres of Marsh Nourishment (one (1) boring for every 50 acres), and twelve (12) undisturbed soils were drilled to the 60 ft. depth below the mud-line in the general areas of the borrow areas.(Six (6) soil borings were drilled below the mud-line for the containment dike and six (6) soil borings were drilled below the mud-line in the general borrow area for the nourishment and enrichment of the marsh creation area.

Analyses included: Estimates of Settlement, Time Rate of Consolidate, Slope Stability Analysis, USACE Method of Planes, and General Construction Recommendations.