State Water Resources Research Institute Program (WRRI)

Details for Project ID 2006LA45B, 2006

A Pilot Study on Modeling and Management of Hurricane- Accelerated Saltwater Encroachment in Coastal Aquifers

Institute: Louisiana
Start Date: 2006-03-01 End Date: 2007-02-28
Total Federal Funds: $15,500 Total Non-Federal Funds: $35,654

Principal Investigators: Frank Tsai

Abstract: Hurricane-induced sea-level rise known as storm surge has disproportionate effect along the Gulf Coast shoreline. The flat topography of the Gulf Coast region allows the coastline to move quite far inland even with only a few inches of sea-level rise, which could accelerate saltwater intrusion in estuaries and coastal aquifers. Some areas in Gulf Coast have been reported to have storm surge more than 20 feet high during Hurricane Katrina. Saltwater encroachment in coastal aquifers is a nationwide problem, which has caused ground water supply shortage, decrease in water availability, drinking water contamination, land subsidence, and estuary ecosystem destruction along the coastal perimeter of the United States. Many coastal metropolitan cities have been experiencing water supply shortage and consequent economic impacts due to severe saltwater intrusion in Southern California, Southern Florida, and Gulf of Mexico coastal areas. Particularly, hurricane-impacted Gulf Coast receives a higher saltwater intrusion threat than any other places due to flat topography, frequent hurricane occurrence, and high storm surge. Although saltwater encroachment into the drinking water aquifers is primarily due to excessive withdrawals, storm surge could expedite saltwater encroachment during the hurricane season. Hurricane-accelerated saltwater intrusion is rarely studied due to the problem complexity and limited data. Nevertheless, understanding the impact of hurricanes on the subsurface hydrological process and saltwater encroachment is important in order to sustain the long-term groundwater resource in Louisiana. This project aims at developing a saltwater intrusion management model to cope with the additional saltwater encroachment by storm surge in the Southeastern Louisiana aquifer system via the optimal operations of the saltwater intrusion barrier (SIB) system. To achieve the project goal, the objectives include (1) saltwater intrusion modeling; and (2) saltwater intrusion barrier system development and management. At the completion of the project, the following issues will be addressed (1) the significance of the hurricane-enhanced saltwater encroachment in the Southeastern Louisiana aquifer system; and (2) the performance of the SIB system during the hurricane period. The accomplishment of the project will also benefit many hurricane-impacted coastal areas wherein the societies are suffering shortages of water resources due to the saltwater intrusion. One example is that the saltwater intrusion management model can be immediately adapted to the critical ground water areas (CGWA) that have been identified by Louisiana Department of Natural Resources (DNR).