New Mexico Geological Society Annual Spring Meeting — Abstracts

The area around the town of Clayton, in northeastern New Mexico, was not a declared groundwater basin until September of 2005. In the years leading up to 2005, battles over groundwater use began to brew and attempts were made to stop drilling of additional water wells for irrigation and stock use. Because there were no regulations in place and the geology of the area had not been studied in a hydrologic framework since the 1960s, there was no basic information for decisions to be made with regards to drilling new wells and use of groundwater. In 2006, the Northeast Soil and Water Conservation District (NESWCD), based in Clayton, decided that they needed a hydrogeology project similar to the Sacramento Mountains hydrogeology project in Otero County. In 2010, the NM Bureau of Geology and Zeigler Geologic Consulting partnered with the NESWCD to help develop a full-fledged hydrogeologic project. The UC Hydrogeology Project is unique in that this project was initially undertaken by members of the community who developed a program of biannual static water level measurements in wells across the county. In addition, the project has support from the vast majority of land owners in Union County. Previous assumptions were that the primary aquifers being utilized were the Tertiary Ogallala Formation and the Upper Cretaceous Dakota Group. However, evaluation of surface bedrock exposures and well cuttings from petroleum exploration wells drilled in eastern Union County demonstrate that the subsurface geology is more complex than might be expected. This subsurface data, along with initial ¹⁴C dates, water chemistry and hydrographs from data recorders installed in a limited number of wells suggest that the aquifer system in Union County is partitioned and substantially more complicated than the “oceans of water” it has often been described as.