A HYDROGEOCHEMICAL ANALYSIS OF SPRINGS IN THE SANDIA AND MANZANO MOUNTAINS, NEW MEXICO

Springs are an important water resource both for anthropogenic use and support of ecosystems in the arid Southwest. During times of drought, the strength of these groundwater systems is a major concern and needs to be more fully understood. During summer 2017, 10 springs were visited in the Sandia and Manzano Mountains to perform an inventory of the springs and the surrounding environment. This work is part of an ongoing effort between students and faculty of UNM and Cibola National Forest.

We collected samples for wildlife demographics, water quality analysis (major ions and stable isotopes), and in field water quality parameters such as pH, TDS, DO, and discharge. Here we focus on the water quality portion. In the lab, we analyzed stable isotopes and major solute composition. Spring samples primarily consist of calcium bicarbonate and calcium magnesium chloride sulfate waters. New analyses show two distinct trends between spring waters that have undergone silicate weathering and carbonate dissolution. We interpret the two trends as representations of varying water-rock interactions. Carbonate dissolution occurs in waters traveling through the Madera limestone aquifer system while silicate weathering occurs as waters travel through faults within the Sandia granite. Stable isotope analyses show that winter snowpack is the primary recharge mechanism of the majority of these waters.

In addition to data collection and analyses, we have made major efforts in compiling all datasets into a regional database (Springs Stewardship Database) to preserve valuable information, make the data accessible to others, and provide important baselines for future comparison. We show here the comparative data for all sites visited in 2017, and compare results with other regional springs.