This report describes the geology and hydrogeology of the southwestern Arroyo Seco quadrangle in Taos County, New Mexico. This area is approximately eight miles north of the Town of Taos and is undergoing extensive residential development. The New Mexico Office of the State Engineer (NMOSE) Hydrology Bureau has identified a need for more detailed hydrogeologic information to improve the NMOSE groundwater simulation model. To this end, I compiled existing geologic, hydrologic, and geophysical data, performed new geologic mapping, and measured water levels in 43 domestic wells. The synthesis of these data leads to an improved understanding of the distribution and flow patterns of groundwater in the area and the relation of groundwater to surface water, in addition to clarifying the geologic controls on the groundwater system.
From October 2000 through June 2002, the New Mexico Bureau of Geology and Mineral Resources conducted geologic mapping on the Pueblo of Picuris as part of a three phase hydrogeologic project for the Pueblo. This work produced a geologic map of the Picuris reservation, and results were summarized in a Phase 1 Final Technical Report dated June 2002. From June 2003 through December 2004, the Bureau continued work on the hydrologic and water quality aspects of the project, which comprised phases 2 and 3 of the study. These phases of work included a well and spring inventory, water level measurements, assessment of the quality of groundwater and surface water, evaluations of the subsurface hydrogeology of aquifers and the interaction between groundwater, surface water and potential sources of contamination in the vicinity of the confluence of the Rio Pueblo de Picuris, Rio Santa Barbara, Rio Chiquito, and Chamizal Creek. This report summarizes the data collected and findings of these final two phases of the hydrogeologic assessment of groundwater and surface water resources on the Pueblo of Picuris.
The Aquifer Mapping Program at New Mexico Bureau of Geology and Mineral Resources (NMBGMR), with funding from Healy Foundation and the USGS, has created the statewide Healy Collaborative Groundwater Monitoring Network for New Mexico. This voluntary network began in 2016 and gathers new and existing data on groundwater levels to help us understand how our state's groundwater resources are changing through time, promote increased awareness of water issues around New Mexico, and provide an important foundation for making informed water-management decisions.
The southern Taos Valley, located southwest of the town of Taos, has been experiencing high growth over the last few decades. In order to address growing water needs in this region, Peggy Johnson, Dr. Paul Bauer, and Brigitte Felix, completed a technical report summarizing the local geology and hydrogeology. Data gathered for this study include geologic maps, well records, new groundwater level measurements and water quality samples, which were compiled with historical data and records. This research describes the important hydrostratigraphic units and aquifers in the region along with geologic/structural controls on groundwater flow. Observations of groundwater flow directions, changes in groundwater levels, distinct water quality and groundwater ages reflect the complex network of faults in the study area and its effects on groundwater.
The issues are a gap in regional scientific information for deep and shallow, sediment-volcanic aquifers and surface waters in the Questa area; including sustainable sources of drinking water, sources of water to springs and streams that feed fisheries and discharge to the Rio Grande, the character of natural, background water quality, and possible impacts from mine-related waters.
The objective of the study was to characterize and interpret the shallow (to a depth of approximately 5,000 ft) three-dimensional geology and preliminary hydrogeology of the Questa area. The focus of this report is to compile existing geologic and geophysical data, integrate new geophysical data, and interpret these data to construct three, detailed geologic cross sections across the Questa area. These cross sections can be used by the Village of Questa to make decisions about municipal water-well development, and can be used in the future to help in the development of a conceptual model of groundwater flow for the Questa area. Attached to this report are a location map, a preliminary geologic map and unit descriptions, tables of water wells and springs used in the study, and three detailed hydrogeologic cross sections shown at two different vertical scales. The locations of the cross sections are shown on the index map of the cross section sheet.
Between August 2006 and April 2007, the New Mexico Bureau of Geology and Mineral Resources conducted a spring inventory and preliminary geochemical sampling as a first step in evaluating the hydrogeologic connections between the ground water and the Rio Grande in Taos County. The objective and principal task was to locate, inventory, describe, and selectively sample the springs of the Rio Grande gorge.
The Taos Plateau in northern Taos County is a high-elevation, basalt-capped plain that lies between the Rio Grande and the Tusas Mountains. The plateau overlaps the New Mexico-Colorado border and forms the west rim of the Rio Grande gorge. The hydrogeologic field investigation of the northern Taos Plateau, conducted between October 2007 and October 2009, is the first comprehensive assessment of groundwater conditions on the Taos Plateau and interactions between local aquifers and the Rio Grande. The investigative approach integrates new and existing geologic, geophysical, hydrologic, and geochemical data. This study has been undertaken in parallel with a major investigation of the springs in the Rio Grande gorge (Bauer et al., 2007). These studies advance understanding of the groundwater system in the northern Taos Plateau, and the interconnection of groundwater and surface water along the Rio Grande in northern Taos County.
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 Arroyo Hondo ground water study reveals a complex, three-dimensional ground water system with multiple hydrostratigraphic units and aquifers. Distribution of the geologic and hydrostratigraphic units is presented through geologic maps and seven detailed cross sections that depict the distribution of geologic and hydrostratigraphic units, well data, surface water features, water levels, faults, and zones of fracturing and sediment layers in volcanic rocks. Cross sections are constructed both parallel and perpendicular to regional ground water flow and illustrate aquifers in the context of the geologic framework, the Rio Grande and the Rio Hondo, local acequias and other surface water features.
