Geological architecture construction for Baton Rouge saltwater intrusion study

Frank T.-C. Tsai Department of Civil and Environmental Engineering, Louisiana State University, 3418G Patrick F. Taylor Hall, Baton Rouge, Louisiana, 70803, USA, Phone: 1-225-5784246, Email: ftsai@lsu.edu

Groundwater is the most important water resource to the public supply and economic development in the Baton Rouge area. The Louisiana Legislature in 1974 established the Capital Area Ground Water Conservation Commission to “promote the orderly development of the ground-water resources in the Capital Area District and to protect the quality of these resources.” Successful management of groundwater resources relies on our understating on the Baton Rouge aquifer system, which has never been satisfactorily understood in the past 40 years. This also presents a serious issue for policy making if the best science is not pursued. This study aims to answer some fundamental questions. What does the Baton Rouge aquifer system look like? Which sands are pumped? Where does freshwater flow through the Denham Springs-Scotlandville fault? Where does salt water leak through the Baton Rouge fault? This study analyzed more than 500 electrical well logs in the Baton Rouge area and constructed an unprecedented geological architecture to answer these questions. Furthermore, this study also developed a grid generation technique to construct saltwater intrusion models for the “1,200-foot” sand, the “1,500-foot” sand, the “1,700-foot” sand, and the “2,000-foot” sand based on the geological architecture. The computer simulation results show that salt water south of the Baton Rouge fault has arrived at the Lula pump station of the “1,500-foot” sand. Salt water in the “2,000-foot” sand is projected to move northward underneath the Mississippi River and eventually will arrive at the west of the Baton Rouge Industrial District. Salt water in the “1,200-foot” sand is projected to move slowly toward the intersection of Interstate 12 Highway and Airline Highway.