Determining The Source And Quality Of Groundwater In The Headwaters Of The Babocomari Watershed
Presenter: Jonathan Hasenstab P81
Co-Author(s): Jonathan Hasenstab, Dr. Andrew Salywon, Dr. Jennifer McIntosh
Advisor(s): Dr. Jennifer McIntosh
1Hydrology & Atmospheric Sciences
The sustainability of groundwater resources in the face of climate change and overextraction is a major concern for many communities with growing populations and/or evolving land use regimes. However, many such communities lack comprehensive hydrologic studies that would help identify the location, nature, and quality of groundwater recharge in these areas. The Babocomari Watershed, which encompasses numerous communities like Huachuca City, Fort Huachuca, Sierra Vista, and Elgin, is undergoing land-use change from ranching to agricultural irrigation. The Babocomari Cienega in the area is also fed by groundwater, and its ability to provide habitat for numerous endangered flora and fauna may be threatened by declines in groundwater levels. Determining the source and quality of groundwater in the Babocomari Cienega and the surrounding areas can improve the modeling and forecasting of the Babocomari watershed’s hydrology and inform future groundwater management decisions. This paper builds upon previous studies on groundwater characterization in the watershed through the collection and interpretation of solute chemistry, stable water isotopes, and age tracers (tritium, radiocarbon). Groundwater ages in the area ranged from modern to more than 7,000 years old, with some groundwater wells containing mixed-age waters which could be vulnerable to anthropogenic influences since they are actively recharged by precipitation. A few groundwater samples had elevated nitrate and sulfate concentrations; additional isotopic analysis is needed to determine whether these solutes are from natural or human sources.