State Water Resources Research Institute Program (WRRI)
Start Date: 2012-03-01 End Date: 2012-02-28
Total Federal Funds: $15,600 Total Non-Federal Funds: $31,927
Principal Investigators: Frank Tsai
Abstract: The goal of the project is to construct detailed hydrostratigraphy of the Southern Hills aquifer system to better understand (1) hydraulic connection from outcrops (recharge zones) to the south boundary of the aquifer system, (2) displacement of aquifers across fault zones, and (3) flow pathways where saltwater crosses the Baton Rouge fault. The Southern Hills aquifer system is designated to be the sole source aquifer for southeastern Louisiana and southwestern Mississippi. The Southern Hills aquifer system also provides an essential amount of high quality groundwater for industries in Louisiana. Due to excessive groundwater withdrawal, saltwater intrusion, drought, climate change, and potential hydraulic fracture operations on Tuscaloosa Marine Shale, water quantity and quality in the Southern Hills aquifer system would be vulnerable. It is essential to understand the complexity of the aquifer system in order to develop reliable groundwater availability models for Louisiana. The scope of the project includes collection of geophysical logs, driller logs and well schedules from the DNR, USGS, LGS and CAGWCC, interpretation of well logs into sand-clay binary hydrostratigraphy, calibration of three-dimensional hydrostratigraphy, and identification of faults in the aquifer system. The objectives of the project are to (1) delineate aquifer structure to better understand hydraulic connection from outcrops to the south boundary of the Southern Hills aquifer system, and (2) delineate fault structure to calculate displacement of aquifers across faults and identify flow pathways that saltwater crosses the Baton Rouge fault. To account for various sources of uncertainty in constructing the Southern Hills aquifer system, we will develop a hierarchical Bayesian model averaging (HBMA) method to deal with uncertainty, which results in multiple possible hydrostratigraphy models. HBMA is a Bayesian technique that assesses uncertainty propagation through different sources and priorities of uncertainties.