Geophysics- and geochemistry-based assessment of the geochemical characteristics and groundwater-flow system of the U.S. part of the Mesilla Basin/Conejos-Médanos aquifer system in Doña Ana County, New Mexico, and El Paso County, Texas, 2010–12

Rio Grande transboundary integrated hydrologic model and water-availability analysis, New Mexico and Texas, United States, and Northern Chihuahua, Mexico

“…This study concluded that about 38 percent of the variation in the geochemical attributes of the Rio Grande could be attributed to flow from bedrock and possible high-temperature sources of groundwater flow, and another 35 percent could be inferred from agricultural activities such as irrigation return flows. Another recent conceptual model of the Mesilla Basin infers features of the groundwater flow (Teeple, 2017) from geochemical attributes represented by five water groups: (1) ancestral Rio Grande (pre-Pleistocene) geochemical group, (2) modern Rio Grande (Pleistocene to present) geochemical group, (3) mountainfront geochemical group, (4) deep-groundwater upwelling geochemical group, and (5) unknown freshwater geochemical group (inferred to be underflow from the Jornada del Muerto Basin). The ancestral Rio Grande water group could also represent some component of upwelling of sedimentary brines and geothermal waters.…”

Rio Grande transboundary integrated hydrologic model and water-availability analysis, New Mexico and Texas, United States, and northern Chihuahua, Mexico

“…Teeple (2017) noted that relatively lower horizontal hydraulic gradients near the El Paso narrows supported geophysical and geochemical interpretations that the El Paso narrows is a region of upwelling of deep groundwater. In addition, Teeple (2017) noted that the buried mid-basin uplift in the Mesilla Basin west of the alluvial Rio Grande Valley compartmentalizes groundwater flow in the Santa Fe Group.…”

“…The regions of large water-level declines and related large unsaturated zones along the Rio Grande alluvial valley near the well fields in Las Cruces, New Mexico, and Canutillo, Texas, are illustrated by the mean groundwaterlevel maps from winter (November through April) 2010-11 in the Rio Grande alluvium (fig. 9B; Teeple, 2017) and in the Santa Fe Group (fig. 9C; Teeple, 2017).…”

“…This study concluded that about 38 percent of the variation in the geochemical attributes of the Rio Grande could be attributed to flow from bedrock and possible high-temperature sources of groundwater flow, and another 35 percent could be from agricultural activities such as irrigation return flows. Another conceptual model of the Mesilla Basin infers features of the groundwater flow (Teeple, 2017) from geochemical attributes represented by five water groups: (1) ancestral Rio Grande (pre-Pleistocene) geochemical group, (2) modern Rio Grande (Pleistocene to present) geochemical group, (3) mountain-front geochemical group, (4) deep-groundwater upwelling geochemical group, and (5) unknown freshwater geochemical group (inferred to be underflow from the Jornada del Muerto Basin). The ancestral Rio Grande water group could also represent some component of upwelling of sedimentary brines and geothermal waters.…”

“…The lower boundary was limited to the bottom of the basement bedrock units or at a total thickness for the formation of 980 ft (300 m), which is deeper than the deepest supply wells. Although there could be some relatively small and deep geothermal upwelling in some regions of the bedrock (Szynkiewicz and others, 2011;Teeple, 2017), these flows were not included in this version of the RGTIHM. Lateral no-flow boundaries represented the contact between the low-permeability bedrock and faults that bound parts of the foothills and the Santa Fe Group in the TRG (figs.…”