21 Hydrogeology Theme Sessions T4, T6, and T7 (Posters)

Thursday, 10 May 2012
8:00 AM - 5:30 PM
Alvarado D&E

EVALUATING DEEP GROUNDWATER INPUTS TO THE ALBUQUERQUE BASIN ADJACENT TO THE SANDIA MOUNTAINS

Paper number: 21-11
Program: Theme Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Within the Albuquerque Basin there are distinct hydrochemical zones defined by chemical and isotopic gradients. Boundaries for the eastern-most hydrochemical zones are located near major faults. Sandia Mountain springs are significant sources of recharge for these hydrochemical zones and the springs are also located along and near major faults. Within the scope of this research, waters collected and analyzed are combined with existing geochemical data of Sandia Mountain springs and Albuquerque Basin wells. The geochemical data and a geologic framework of the area are used to evaluate pathways of groundwater recharge and possible sources and concentrations of contaminates. Nine of the Sandia Mountain springs recharge the Eastern Mountain Front hydrochemical zone and have an average pH of 7.69, average temperature of 14.5°C, and an average conductivity is 665 µS/cm. To the south, the Tijeras fault zone and Tijeras arroyo hydrochemical zones have seven springs with an average pH of 6.92, average temperature of 12.7°C, and an average conductivity of 1077 µS/cm, with the highest value at 3500 µS/cm.

Recently, the City of Albuquerque has drastically reduced its mining of groundwater, transitioning to surface waters for part of municipal demands. Groundwater levels appear to be recovering but it is unclear how the water quality will be affected. Utilizing geochemical models (Phreeqc and Geochemist’s WorkBench) we will create mixing and water rock interaction scenarios to better understand the hydrochemical variations in the aquifer. Geologic structures can affect aquifer hydrochemistry by introducing deep fluids which can be sources of salinity and contaminants such as arsenic, uranium and fluoride. Applying multiple tracers, e.g., stable isotopes, major ion concentrations, strontium isotopes, and noble gases, will help to evaluate how the geochemistry of spring waters and fluid inputs along regional geologic structures may impact the groundwater quality.