296-5 Water Quality and Recharge within the Sandia Ranger District, Cibola National Forest

Session: Innovations in Research of Groundwater-Surface Water Interactions over Multiple Spatio-Temporal Scales (Posters)

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The Sandia Mountains, northern New Mexico, represent a valuable regional site for studying aquifer sustainability in the context of climate change. This research aims to sample, analyze, and identify geochemical characteristics of wells, snowpack, and springs of the Sandia Mountains, comparing newly collected data with legacy datasets from the University of New Mexico and Cibola National Forest (CNF). Our methodology encompasses three primary tasks: field sampling at both established and new locations, comprehensive laboratory analysis, and comparative data assessment. Laboratory work includes alkalinity titrations, stable isotope analysis of water isotopologues using Cavity Ringdown Spectroscopy, and major ion characterization via ion chromatography, inductively coupled plasma-optical emission spectroscopy. We use end-member analysis and geochemical modeling to determine the proportion of groundwater produced through winter snowpack versus monsoonal recharge using multiple geochemical tracers. We present 10 new analyses from our ongoing study and compare over 150 previous analyses from 2012-2024.

Springs of the Sandia Mountains emerge from a regional karst aquifer, the Pennsylvanian Madera limestone. Hydrochemistry of the springs shows water-rock interaction consistent with limestone dissolution. We use the stable isotope variations among rain, snow and springs to evaluate winter vs. monsoonal contributions to spring discharge of CNF watersheds. Calcite supersaturation of Sandia waters, evidenced by both geochemical modeling and modern travertine deposits, fluctuates seasonally. These findings have significant practical applications by informing current recharge patterns and water quality trends, through which local authorities can better predict water availability and plan for future needs.         

Beyond regional implications, this research addresses the growing precarity of local water resources by offering insights into changing precipitation patterns and recharge dynamics over the past decade. Understanding the balance between winter snowmelt and monsoonal rain contributions to groundwater is increasingly crucial as climate change alters precipitation regimes in arid environments. Stable isotope geochemistry provides a viable approach for distinguishing between these precipitation sources, enabling detailed analysis of seasonal contributions to recharge. This technique also allows for long-term comparisons with historical records, enhancing our ability to detect shifts in hydrologic inputs over time. By identifying trends and changes in these inputs, this study hopes to contribute to a broader understanding of mountain hydrogeology in arid environments worldwide.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8999

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