New Approaches to Sediment Management on the Inner Continental Shelf Offshore Coastal Louisiana

Coastal restoration in Louisiana requires clean sands for beach and dune restoration, whereas mixed sediments are required to rebuild marshes. The Louisiana coastal erosion problem is especially dire because it occurs on several fronts with the narrowing and overtopping of barrier islands and loss of back barrier bay and interior marshlands. Coastal restoration efforts in Louisiana depend on emplacement of sediment to build up barrier island and deltaic systems. Discovery of usable sediment is thus a vital factor in restoration efforts because up to 80% of some restoration project budgets can be allocated to exploration, exploitation, and emplacement of sediment. Because this cost is directly proportional to the distance of borrow sources from the project area, the cost-effectiveness of barrier island restoration and marsh creation depends on locating sufficient sediment volumes that are suitable for placement on beaches and dunes and for creating marshes. The restoration of Louisiana's barrier islands and the creation of coastal marshes are critically dependent on the availability of suitable modern marine and riverine sediments and other buried fluvio-deltaic deposits. It is thus imperative that a comprehensive sediment management plan be developed to systematically and efficiently identify and allocate suitable sediment resources. At present, coastal and barrier island restoration projects are included in regional planning efforts, and the restoration project is decided before sediment sources are considered. The new approach proposed here is based on planning projects around locations of dredgeable sedimentary deposits in order to optimize sediment resources. Centralization of voluminous historical geoscientific and oil and gas infrastructure data is being accommodated in a new data management system called the Louisiana Sand Resource Database (LASARD). Managing sediment resources more strategically optimizes regional planning strategies and reduces construction costs. The Louisiana Sediment Management Plan (LASMP) conceptualizes systematic planning and better coordination of essential components of the huge restoration and protection effort currently undertaken in Louisiana.