Chemical Dynamics of a Confined Limestone Aquifer

The evolution of groundwater in the Roswell Limestone Aquifer is measured using some rather ordinary and easily determined characteristics of the water. Randomness caused by analytical error and matrix inhomogeneity is suppressed by dividing the study area into subsections on the basis of hydrologic function and using averaged values of the measured characteristics to describe each subdivision.

It is found that temperature, ionic solute concentrations, calcite saturation, and dissolved oxygen content change in a reasonably steady and monotonic manner as the water flows from the recharge to the discharge region.

Simple models are developed to quantify the oxygen and temperature measurements. On the basis of these models the groundwater flow is found to be a factor of 6 faster in the northern part of the Roswell Limestone Aquifer and the residence time is a factor of 3 longer in the southern part. Solute concentrations indicate intrusion into the northeast corner of the Limestone Aquifer from an upper Alluvium Aquifer.

Project No. B-048-NMEX