The Mesilla Basin is one of the southernmost basins of the Rio Grande Rift system, extending from south-central New Mexico across state and international boundaries into west Texas and northern Chihuahua, Mexico. The hydrology of the Mesilla Basin region has been subject to extensive investigations for over a century (e.g., Slichter, 1905; Theis, 1938; Sayre and Livingston, 1945; Conover, 1954; Leggat et al., 1962; Hawley et al., 1969; King et al., 1971; Wilson and White, 1984; Hawley and Lozinsky, 1992; Nickerson and Myers, 1993; Kennedy et al., 2000), as summarized by Hawley et al. (2001), who is paraphrased here. The eastern margin of the Mesilla Basin is defined by the Organ-Franklin-Juarez mountain chain, and the western margin by fault block and volcanic uplands of the East Potrillo Mountains and West Potrillo basalt field. The Robledo and Doña Ana Mountains define the northern end of the Mesilla Basin. The northeast end of the basin is transitional with the Jornada del Muerto Basin. The southern basin boundary with the Bolson de los Muertos in northern Chihuahua state is less well-defined. The entrenched Mesilla Valley of the Rio Grande crosses the eastern margin of the Mesilla Basin, where the cities of Las Cruces, NM, El Paso, Texas, and Juarez, Mexico exploit groundwater resources from the basin aquifers. Regional groundwater and surface water flow is to the southeast toward El Paso, through a gap separating the Franklin Mountains from Sierra Juarez to the south.
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.
The Jornada del Muerto is a north-south trending basin lying to the east of the main Rio Grande Rift system in Socorro, Sierra, and Doña Ana Counties, New Mexico. The basin is ~160 miles long, averages 20 miles in width, and deepens to the south. The basin is bounded to the east by Chupadera Mesa and the Oscura and San Andres Mountains, and to the west by the Caballo and Fra Cristobal Mountains and the San Pasqual Platform. The south end of the Jornada del Muerto Basin merges imperceptibly with the northeast end of the Mesilla Basin. Unlike the Rio Grande Rift basins to the west, the Jornada del Muerto is a broad syncline that plunges to the south-southeast, formed between east-dipping Paleozoic and Mesozoic strata along the Caballo-Fra Cristobal Uplift and west-dipping Paleozoic strata in the San Andres Mountains. The basin is thus not part of the late Tertiary Rio Grande Rift extensional system, and Santa Fe Group basin-fill sediments are generally less than 350 feet thick (Chapin, 1971; Lozinsky, 1987; Roybal, 1991). The Jornada Draw fault zone runs from north to south and roughly parallels the hinge of the syncline. This fault zone significantly affects the groundwater system in the central part of the basin (Newton et al., 2015).
The San Luis Basin is the northernmost and largest basin of the Rio Grande Rift system in New Mexico. Most of the basin is located in Colorado, where it merges to the north with the Upper Arkansas River graben (Grauch and Keller, 2004). The basin is ~150 miles long and 55 miles wide, and has the general form of an east-dipping half graben. Basin-fill material is composed of Tertiary-Quaternary sediments of the Santa Fe Group and late Cenozoic volcanics (Kelley et al., 1976). The basin is bounded to the west by the Tusas and San Juan Mountains and to the east by the Sangre de Cristo Mountains and the Sangre de Cristo fault zone. The deepest part of the basin is found in the Taos graben, a narrow zone 6 to 18 miles wide adjacent to the Sangre de Cristo mountain front (Grauch and Keller, 2004). The southern part of the basin is occupied by the Taos Plateau, which is composed of Pliocene basalt flows that overlie Santa Fe Group basin fill. The southeastern margin of the basin is defined by the Embudo fault zone, which separates the east-tilted San Luis Basin from the west-tilted Española Basin to the south (Bauer and Kelson, 2004).
The Roswell Artesian Basin occupies over 4,000 square miles in the lower Pecos Valley in Chaves and northern Eddy Counties, and is one of the most intensively farmed regions in the state outside the Rio Grande Valley (Welder, 1983; Land and Newton, 2008). The eastern margin of the basin occurs just east of the Pecos River; the northern boundary is approximately defined by Macho Draw north of Roswell; and the southern end of the basin is located at the Seven Rivers Hills north of Carlsbad. The western margin of the basin is not as well-defined, but is usually located west of Roswell on the Pecos Slope near the Chaves-Lincoln County Line. The basin derives virtually all of its irrigation and drinking water from groundwater stored in a karstic artesian limestone aquifer contained within the Permian San Andres and Grayburg Formations, and from a shallow unconfined aquifer composed of Tertiary-Quaternary alluvial material deposited by the ancestral Pecos River. The Roswell Basin has been described by many workers as a world-class example of a rechargeable artesian aquifer system (e.g., Fiedler and Nye, 1933; Havenor, 1968).
The Capitan Reef is a fossil limestone reef of middle Permian age that is dramatically exposed along the southeast flank of the Guadalupe Mountains in Eddy County, New Mexico, reaching its maximum elevation in west Texas, in Guadalupe Mountains National Park. In New Mexico, the reef serves as the host rock for the Big Room in Carlsbad Cavern. A few miles northeast of Carlsbad Caverns National Park, the reef dips into the subsurface and passes beneath the city of Carlsbad, where it forms a karstic aquifer that is the principal source of fresh water for that community (Land and Burger, 2008). The Capitan Reef continues in the subsurface east and south into Lea County, then south for ~150 miles to its southeasternmost outcrop in the Glass Mountains of west Texas.
The Estancia Valley is a relatively flat-floored, closed physiographic basin with internal drainage, occupying ~2,000 square miles in central New Mexico. The valley, most of which lies within Torrance County, is bounded to the west by the Manzano Mountains, to the east by the Pedernal Hills, and to the south by Chupadera Mesa. The northern margin of the basin is less well-defined, merging with a high plateau area in southern Santa Fe County (Meinzer, 1911; Smith, 1957; White, 1994). Highest elevations in the Estancia Valley (>9,000 feet) occur along the western rim of the watershed, on the east flank of the Manzano Mountains. Lowest elevations (~5,900 feet) are found along the central topographic axis of the basin, where a north-south trending series of playas formed by deflation are incised into the valley floor (Bachhuber, 1982). Because the Estancia Valley is a topographically-closed basin, the only outlet for precipitation that falls within the basin boundaries is by evapotranspiration, primarily from the playa lakes.
The Española Basin is one of the northernmost basins of the Rio Grande Rift in New Mexico, and has been subject to extensive investigations in the past several decades (e.g., Kelley, 1978; Manley, 1979; Cordell, 1979; Golombek, 1983; Biehler et al., 1991; Johnson et al., 2008; Grauch et al., 2009). Although the Española Basin has the general form of a west-dipping half-graben, it exhibits a high level of structural complexity, consisting of a series of narrow, deep axial troughs in an otherwise shallow basin (Ferguson et al., 1995). The basin is ~50 miles long and 18 to 40 miles wide, and is linked to the east-dipping Santo Domingo Basin to the south at the La Bajada constriction. The basin is connected to the north with the east-dipping San Luis basin at the Embudo constriction. The Santa Fe Embayment occupies the southeast corner of the basin.
The Tularosa Basin is an elongate, north-trending intermontane basin of the greater Rio Grande Rift system, occupying approximately 6,500 square miles in south-central New Mexico. The basin is bordered by Sierra Blanca and the Sacramento Mountains to the east; and the San Andres, Organ, and Franklin Mountains to the west. The basin merges to the south with the Hueco Bolson, extending into west Texas. Extensive fault systems with several thousand feet of vertical displacement separate the basin from the east and west-flanking uplifts (Lozinsky and Bauer, 1991). As regional uplift progressed, concurrent erosion of the surrounding highlands has resulted in deposition of more than 6,000 feet of alluvial basin-fill material, consisting of unconsolidated to weakly-cemented gravel, sand, silt and clay deposited in a series of coalescing alluvial fans around the margins of the basin. The basin fill is underlain by consolidated bedrock, thought to consist largely of Paleozoic carbonates.
The Mimbres Basin is a structurally complex region in southwestern New Mexico, extending over an area of more than 5,000 square miles in parts of Grant, Luna, Doña Ana and Sierra Counties, and straddling the border with the Mexican Republic. The region has been subject to extensive geologic, geophysical, and hydrologic investigations over a period of almost a century, including Darton (1916), White (1931), Trauger (1972), Hanson et al. (1994), Hawley et al. (2000), and Kennedy et al. (2000). The Mimbres Basin is located at the intersection of the Basin and Range, southern Rio Grande Rift, and southern Transition Zone tectonic provinces (Mack, 2004). Dominant structural features in the region are northwest trending faults and folds associated with the Laramide orogeny, Tertiary magmatism and Quaternary tectonism (Finch et al., 2008). The greater Mimbres Basin is made up of an interconnected group of hydrologic sub-basins separated by fault-bounded uplifts, bounded to the east by the Goodsight Mountains, Sierra de las Uvas, and basalt flows and cinder cones of the West Potrillo Mountains. The Continental Divide defines the northern and western boundaries of the Mimbres Basin. The only major surface drainage in the basin is the Mimbres River (Hawley et al., 2000; Connell et al., 2005; Finch et al., 2008).
