A Design Model for a Scavenger Well Couple in Baton Rouge, Louisiana
Tuesday, May 6, 2014: 11:30 a.m.
Blake (Westin Denver Downtown)
Vic Kelson, Ph.D., PE, CGWP
,
Layne Hydro, Layne Christensen Company, Bloomington, IN
Rhett Moore, PH
,
Layne Hydro, Layne Christensen Company, Bloomington, IN
Baton Rouge satisfies much of its public water-supply demands by withdrawing water from deeply buried aquifers that underlie the city. Since the 1960s, brackish water has been migrating into the "1500-foot sand" aquifer, and that brackish water now threatens the long-term sustainability of the Lula pumping station. The author participated in a pair of studies, funded by Baton Rouge Water Company, to assess the potential for halting the migration of chlorides towards the Lula station.
Since the chlorides are concentrated at the bottom of the aquifer, it is desirable to recover as much of the fresh water as possible without resorting to desalinization. It was proposed to construct two nearby wells, one completed in the brackish section of the aquifer and the other completed in the fresh section. By carefully regulating the pumping rates of the two wells, it is expected that the fresh water can be retrieved. However, there were many questions about the design of the "well couple," including the choices of screen length, the locations of the two wells relative to the ambient flow direction, and how well the system would work as brackish water intrusion continued over time.
The author developed a 3D model of a well couple using the 3D analytic element code TimML (Bakker 2005) to evaluate the performance of the well couple, and the effects of various design options. The model made it possible to compare alternative designs and to determine the best arrangement of well screens, evaluate screen length options, and to manage the future continuing encroachment of brackish water in the aquifer. The results of the model were used in the final design of the scavenger-well couple that is now being constructed in Baton Rouge. It is expected that the well couple will be brought online in 2014.
Vic Kelson, Ph.D., PE, CGWP, Layne Hydro, Layne Christensen Company, Bloomington, IN
Vic Kelson has been developing groundwater flow models and model codes since 1993. He earned a B.S. in Chemical Engineering at the Colorado School of Mines. His first experience working with groundwater was studying a contamination problem at the fertilizer plant where he first worked after college. Upon returning to graduate school, Kelson became fascinated with groundwater models and has been developing models, and model codes, ever since. He has been the developer of numerous codes using the analytic element method, especially for design of riverbank filtration systems.
Rhett Moore, PH, Layne Hydro, Layne Christensen Company, Bloomington, IN
Rhett Moore is a professional hydrologist with expertise in hydrologic investigations for resource planning and development. After obtaining his bachelor's degree from the University of Tennessee in Engineering and his master's degree at Indiana University in Environmental Science, he worked for eight years with the U.S. Geological Survey planning and managing large and small-scale hydrologic field monitoring investigations. For the last 14 years, Moore has managed water-supply development and optimization projects for various municipal, private, and industrial clients located throughout the U.S.
