GGI Publishes Zuni Reservation Spring Inventory
GGI has recently published Recharge sources and characteristics of springs on the Zuni Reservation, New Mexico in the New Mexico Geological Society 64th Annual Field Trip Guidebook. This study involved an assessment of 29 springs on the Zuni Reservation. The study was conducted between 2007 and 2009 in four areas of the reservation (Nutria, Pescado, Dowa Yalanne-Black Rock, and Ojo Caliente) that represent areas with concentrations of springs or relatively large-volume spring discharge. The assessment of each spring included geologic and geomorphic mapping; measurement of spring discharge; measurement of field water quality parameters; water sample collection and analysis for major cations and anions, stable isotopes and tritium; identification of the source aquifer; and preliminary assessment of flora and fauna. The study was conducted in collaboration with the Zuni Conservation Program.
This investigation demonstrated that recharge sources for springs on the reservation include the Zuni Mountains to the northeast, the North Plains to the east, and isolated high mesas within the Zuni Reservation. Most springs on the Zuni Reservation are recharged by winter precipitation, and snowpack moisture content is an important factor in spring recharge. Summer monsoonal precipitation is a secondary recharge source that may be an important source of recharge on the high mesas within the reservation and appears to be the primary recharge source for some low discharge springs. Spring discharge represents pre-1952 recharge for areas such as Ojo Caliente and Pescado, whereas the Black Rock springs exhibit submodern (more recent) recharge. Nurtia Spring represents a mixture of pre-1952 and submodern recharge. Spring discharge measurements from this study, when compared to previous investigations, show an apparent decline in spring discharge on the reservation between 1972 and 2009. This could be due to increased groundwater diversions in the Zuni Mountains, the Zuni River basin, and regionally in the San Andres-Glorieta aquifer, fluctuations in precipitation, variations in measurement methodologies, or a combination of these factors.