Impact of 2010-2011 Drought on Wilcox Aquifer Groundwater Supply Levels and Water Quality
Douglas Carlson¹, Marty Horn¹, Gary Hanson², Amanda Lewis², and Dillion Soderstrom³
¹Louisiana Geological Survey, Louisiana State University, Baton Rouge, Louisiana
²Red River Watershed Management Institute, Louisiana State University-Shreveport, Shreveport, Louisiana
³Department Louisiana State University-Shreveport, Shreveport, Louisiana
The Shreveport area experienced a prolonged drought between April 2010 and January 2012. The drought impacted the Wilcox Aquifer by reducing recharge, increasing demand, and lowering potentiometric levels. These physical changes impacted water chemistry in the principal sand interval that supplies domestic water wells in the area.
The decline of recharge rates was indicated by reduction of baseflow rates for four streams within the study area while demand for water increased. Potentiometric level declines were documented by measurements at six monitoring stations. The drought increased the rate of potentiometric level decline within the Wilcox Aquifer. In the summer of 2011 the rate of decline of potentiometric level increased rapidly in isolated areas.
These changes in baseflow and potentiometric levels appear to have changed water quality within the second and deeper aquifer sand within the Wilcox, which is the principal sand used for domestic water supply in the study area. The changes of chloride and sodium concentrations indicate that water levels are being drawn down causing wells to draw water from lower more saline portion of the second sand.
AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012