The agricultural economy of Union County in northeastern New Mexico is highly dependent on groundwater. Ongoing drought, large new groundwater appropriations both within the county and in adjacent parts of Texas, and large water level declines in wells have led to concern amongst county residents over groundwater supplies. This report documents the finding of a hydrogeology study to better understand the aquifers utilized in east-central Union County. The study began in 2010 and covers 650 square miles, from north of Clayton to south of Sedan, and east to the state line. The study was jointly sponsored by Northeastern Soil and Water Conservation District (NESWCD), the Aquifer Mapping Program of the New Mexico Bureau of Geology and Mineral Resources, and Healy Foundation.
Between 1598 and the 1880s, El Camino Real de Tierra Adentro (El Camino Real) served as a 1,600 mile long trade route between Mexico City and San Juan Pueblo/Ohkay Owingeh, New Mexico (north of Santa Fe). El Camino Real transects the Jornada del Muerto, located in southern New Mexico (see below figure). This stretch of the trail is thought to have been one of the most feared sections along El Camino Real due, primarily, to the scarcity of water.
The study area is located primarily in the central portion of the Jornada del Muerto Basin, extending from just North of Engle to just south of Point of Rocks and spanning the entire basin from the Caballo Mountains in the west to the San Andres Mountains to the east.
We characterized the local geology and hydrogeology of the central Jornada del Muerto with a purpose of identifying features that likely influenced the location of El Camino Real de Tierro Adentro. This study aimed to assess the relationship between the location of the trail and parajes (campsites) and water sources that would be available to travelers on the trail. The study was funded by the New Mexico Spaceport Authority (NMSA) and is the fulfillment of one of the measures specified in a mitigation plan that identifies a series of measures specifically intended to mitigate adverse effects to El Camino Real.
The San Marcial and Engle Basins are axially-linked basins of the southern Rio Grande Rift system that connect the Socorro Basin with the Palomas Basin to the south (Connell et al., 2005). The Engle Basin is an east-tilted half graben containing ~2,000 feet of basin-fill material. Compared to other groundwater basins of the Rio Grande Rift, information specific to these two basins is limited. The compiled data contains only 32 data points for both basins. This very incomplete record indicates water in these basins is relatively fresh, with only four wells exceeding 1000 mg/l TDS.
The southern Española Basin, in the Santa Fe region, was the focus of a multi-year, multi-disciplinary hydrogeologic study by the Aquifer Mapping Program, in collaboration with the New Mexico Office of the State Engineer (NMOSE), the U.S. Geological Survey (USGS) and other agencies. The purpose of this study was to improve the understanding of the water resources within the basin, which serves as the primary source of drinking water for most of the area’s population.
The goals of this study were to delineate areas of groundwater recharge, determine directions and rates of groundwater movement, and better understand the interactions between different aquifers and between the groundwater and surface water systems. Data collected from 2005 to 2009 include geologic mapping, frequent water level measurements in wells, single time and repeated well and spring sampling, precipitation measurement and sampling, fracture orientation measurements, and stream flow measurements.
Desalinated brackish water has been discussed in New Mexico as a possible alternative supply for drinking water. The communities of Tularosa and Alamogordo continue to explore using brackish water as a municipal water supply, and plans are quite advanced toward production. The communities in this region are actively seeking information to insure protection of fresh water supplies while implementing the use of alternate source water sources - brackish groundwater.
Three-dimensional, geographic information system (GIS)-based, subsurface geologic models are becoming increasingly common tools for visualizing, evaluating, and managing subsurface resources. The New Mexico Bureau of Geology and Mineral Resources Aquifer Mapping Program is developing 3D hydrogeologic-framework models of groundwater basins in New Mexico, including the Delaware Basin in southeastern NM. These models include a suite of geologic raster surfaces, geologic control points, aquifer boundaries, groundwater-level, water-depth, and water-quality data compiled in a readily available GIS map package. The result is a repository of pertinent shallow subsurface data for a given groundwater basin.
The characterization of the Placitas area hydrology in the late-1990s was an important step for water resource planning and development. Local water levels were declining due to increased population and demand on groundwater supplies, with drought conditions in the mid-1990s. The Bureau of Geology initiated a study in 1997 to characterize the availability and quality of groundwater and surface water resources in the Placitas area. Findings were interpreted with detailed geologic maps and cross sections that supported a hydrogeologic conceptual model of groundwater flow and occurrence. The study was completed in 2002 and has been incorporated into the Placitas Area Development Plan by Sandoval County.
As part of the New Mexico Water Data Initiative, this 3-year project, cooperatively funded with the US Bureau of Reclamation's WaterSMART program, will improve water data accessiblity, efficiency of data collection and sharing, as well as developing tools to help address water management in the Pecos Valley region of southeastern New Mexico.
Several thousand water-level measurements spanning over 50 years, from over a thousand wells, were used to create aquifer lifetime projections for the High Plains aquifer in eastcentral New Mexico. Lifetime projections were made based on past water-level decline rates calculated over ten- and twenty-year intervals. Projected lifetimes were calculated for two scenarios. One scenario is the time until total dewatering of the full saturated thickness of the aquifer, and the other scenario is the time until a 30-ft saturated thickness threshold is reached, which is the minimum necessary to sustain high-capacity irrigation wells. Agricultural water use has largely determined water-level decline rates in the past. Assuming future decline rates match those of the past ten to twenty years, the two scenarios may be viewed as the usable aquifer lifetime for domestic and low-intensity municipal and industrial uses, and the usable lifetime for large-scale irrigated agriculture.
