Northeastern New Mexico is a geologically diverse area that includes the upper Pecos and Canadian river valleys, the eastern margin of the Sangre de Cristo Mountains, and the Raton and Las Vegas Basins, two north-trending assymetric structural basins formed during the late Cretaceous-Paleogene Laramide orogeny. The Raton and Las Vegas Basins are separated by igneous intrusive rocks of the Cimarron Arch, near Cimarron, NM. The gently-dipping eastern margins of these basins are defined by the Sierra Grande Arch and the Raton-Clayton volcanic field (Kelley, 2015; Broadhead, 2015).
The New Mexico Bureau of Geology and Mineral Resources with New Mexico Tech is beginning a groundwater and surface water study along the Rio Grande between San Acacia and Fort Craig. The NM Interstate Stream Commission has established a funding agreement with New Mexico Tech and the Bureau of Geology to investigate hydrologic connections among the Rio Grande, the Low Flow Conveyance Channel (LFCC), the riparian aquifer, and the riparian ecosystem along the San Acacia Reach of the Rio Grande. In particular, the project aims to understand the effects of diverting monsoon-season flood peaks from the Rio Grande into the LFCC under certain river-drying conditions.
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 San Agustin Basin is a closed intermontane basin on the northern edge of the Mogollon Plateau, and within the Datil-Mogollon volcanic field of southwestern New Mexico, extending across ~2,400 square miles in Catron and westernmost Socorro Counties. Myers et al. (1994) conducted an investigation of the hydrogeology of the basin, which is summarized here. The San Agustin Basin is bounded to the west and south by the Continental Divide, to the north by the Datil and Gallinas Mountains, and to the east by the San Mateo Mountains. The most recent structural activity in the region was late Tertiary Basin and Range faulting, which formed the San Agustin and Cuchillo Negro grabens. The Plains of San Agustin, which occupy the northeast-trending San Agustin graben, were covered by several large lakes during late Pleistocene time. Playas now occupy these former lake beds. There is no perennial streamflow in the basin.
It is surprising that New Mexico does not have a detailed map of all of the productive and accessible aquifers across the state. In a state with as little as 0.24% of our land surface covered with water (the least in the country!), having detailed maps of our groundwater resources and aquifers, is essential. Some of our neighboring states, like Texas and Colorado, have these maps already available, and are successfully being used to administer and conserve water. We have started a new multi-year project to develop 3D maps of aquifers.
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.
Since 2007, the sparsely populated San Agustin Plains has been a controversial basin: a company applied for a permit to pump 54,000 acre-feet per year and to pipe that water to a region outside of the Plains. In 2009, the neighboring watershed to the south, Alamosa Creek — the only perennial stream in the region — faced similar pressure with a mining company exploring for beryllium. In response to these pressures and questions about the hydrogeology of this area, the NM Bureau of Geology began an integrated geologic and hydrologic study of the basins in 2009.
As part of development of a regional source water protection plan, in 2015–2016 the New Mexico Bureau of Geology and Mineral Resources performed a technical review of existing hydrogeology studies in Curry and Roosevelt counties in east-central New Mexico. Additionally, groundwater quality was tested in numerous wells, and groundwater levels were examined to provide up-to-date information on the availability of groundwater in the region. This report describes the results of the hydrogeologic review and findings from the groundwater study.
