Quantifying the Change in Volume of Water in the Sparta Aquifer, Northern Louisiana
Tuesday, December 5, 2017: 2:40 p.m.
The Sparta aquifer, generally a confined aquifer, is the primary source of groundwater in north-central Louisiana. Increasing groundwater withdrawals at concentrated locations from wells screened in the Sparta aquifer, have resulted in regional water-level declines. Recent studies, including potentiometric maps and a groundwater flow model, have assessed the impacts of withdrawals on water levels in Sparta aquifer, and water levels and saltwater encroachment continue to be monitored at a network of wells screened in the aquifer in Louisiana. However, questions still persist regarding the volume of available water and the long-term sustainability of the aquifer. To address these concerns, the U.S. Geological Survey (USGS) is developing a web-based tool that can compile these products into a single platform, whereby water-resource managers can easily assess the status of available water resources for a given location. The tool will provide estimates of changes in the volume of water in the Sparta aquifer from 1900 predevelopment conditions through 2012. Storage change will be evaluated using two methods: 1) Geographic Information Systems analysis and comparison of previously published USGS structure maps and potentiometric surfaces of the Sparta aquifer; and 2) analysis of simulated water storage in the aquifer derived from a groundwater-flow model. The interactive web tool, once developed, will allow users to compare results from both methods in a publically available visual mapping platform. Knowledge of the change in water volume within the Sparta aquifer will be useful for assessing recharge rates and could improve public understanding of the impacts of withdrawals over time.