Sand Resources, Regional Geology, and Coastal Processes for Shoreline Restoration: Case Study of Barataria Shoreline, Louisiana

By

KINDINGER, JACK L.

US Geological Survey, Center for Coastal Marine Regional Studies, St. Petersburg, FL,

PENLAND, S.

Coastal Research Laboratory, Department of Geology and Geophysics, University of New Orleans, New Orleans, LA,

FLOCKS, J. G.

US Geological Survey, Center for Coastal Marine Regional Studies, St. Petersburg, FL,

KULP, M.

Coastal Research Laboratory, Department of Geology and Geophysics, University of New Orleans, New Orleans, LA,

BRITSCH, L. D.

New Orleans District, U.S. Army Corps of Engineers, New Orleans, LA

The Louisiana barrier shoreline of Barataria Basin lies within the western Mississippi River delta and has undergone significant retreat and reduction in size during the past 100 years. The most practical restoration method to rebuild these shorelines is sand nourishment. Seismic and sonar interpretations verified with geologic samples (vibracores and borings) indicate that there are nine sand targets within the Barataria study area that meet or exceed the minimum criteria for potential resource sites. However, near surface lithologies in the basin are typically silts and clays. Locating suitable sand resources for shoreline restoration is challenging. The sand units are associated with geologic depositional systems such as ebb-tidal deltas, distributary mouth bars, and channel fill (undifferentiated fluvial or tidal inlet channels). In this study, we identified 396 to 532 mil yd³ (305.8 to 410.8 mil m³) of potential sand deposits for shoreline restoration.

Previous studies using less dense survey methods greatly over estimated sand resources available in this area. Many fluvial channels reported as sand-filled are mud-filled. Contraries to common opinion few fluvial subsystems in this region have abundant sand resources.

The nine potential sand targets found consist primarily of fine sand and can be delineated into three surficial and six buried features. The surficial features contain approximately 10% of the total sand resources identified. At least 90% of the sand resources found need overburden sediment removed; almost 570 mil yd³ (438.5 mil m³) of overburden will need to be removed and included if the entire resource is mined.