CH2M HILL and subcontractors DHV and Deltares have received a contract from the U.S. Army Corps of Engineers to undertake a modeling study for the restoration of the Mississippi Barrier Islands.
A chain of islands (Barrier Islands) along the Mississippi coast of the Gulf of Mexico protects the mainland against waves and other effects of storm surges. These islands are a part of the Gulf Islands National Seashore and are rich in wildlife and natural features. The islands are subject to natural erosion due to tides, waves, and tropical storms and hurricanes. Historic dredging of the Pascagoula navigation channel connecting the port at the Mississippi coast to the Gulf has further contributed to the erosion of these islands. One of the largest of the Barrier Islands, Ship Island, was breached by Hurricane Camille in 1969 and further impacted by Hurricane Katrina in 2005, which created a 3.5 mile wide gap. This loss of land negatively impacts the natural values of the islands and the Mississippi Sound estuary, and reduces protection of the mainland from storm surges.
Following Hurricane Katrina, the United States Army Corps of Engineers (USACE) implemented the Mississippi Coastal Improvements Program which includes restoration of the sediment budget, including littoral zone geologic processes around Ship, Horn, and Petit Bois islands to their natural state as much as possible. The restoration effort seeks to return sediment into the system within the barrier islands to pre-Hurricane Camille conditions as much as possible given the realities of navigation channel dredging, climate change (sea level rise, increased frequency of storms, etc.) and other anthropogenic activities. As a part of the environmental assessment to validate the current designs and to evaluate the impacts, the USACE requested specialist advice from DHV and
Deltares, as subcontractors to
CH2MHILL.
The consortium will carry out a study to predict the behavior of the addition of a large volume of sand (22 million cubic yards) in the littoral system both at the breach (“Camille Cut”) and at the eastern end of the Ship Island. Advanced computer models will be applied to study in detail the development of the nourishment and the morphological effects of various design alternatives. The results of the study will be presented in several workshops with experts from all parties involved. As a part of knowledge transfer, training to the USACE staff on the modeling software and application will also be provided. The models developed during the study will be used for fine-tuning of the designs, monitoring and adaptive management.