Water Resources Professional Project Reports

Document Type

Report

Publication Date

Spring 2003

Abstract

For this project fifty-four water samples were collected from sites throughout the Roswell groundwater basin in southeastern New Mexico that were previously sampled by Hoy and Gross in the 1970's. These data sets were used to evaluate the transience of δ18O values in the basin in hopes of simulating transient conditions with a compartmental mixing cell model. No long-term trend in the data was established. A compartmental mixing cell model was developed and calibrated with the spatial distribution of δ18O. The model was run using the steady-state simulation and produced estimates of groundwater flow paths, volumetric flow rates, recharge rates and residence times. The results estimate the total recharge to the carbonate aquifer as 230,900 afy, slightly lower than previous estimates. Furthermore, the model predicts that 92,400 afy of the recharge to the carbonate aquifer is provided by underflow from deeper units whose source waters originate in the Sacramento Mountains. Mean groundwater ages in the basin ranged from 234 to 924 years and were strongly influenced by the fraction of recharge derived from the underflow component.

Keywords

δ18O, groundwater, Roswell, mixing cell, carbonate aquifer

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