SPRINGS OF THE RIO GRANDE GORGE, TAOS COUNTY, NEW MEXICO: INVENTORY, DATA REPORT, AND PRELIMINARY GEOCHEMISTRY Final Technical Report October 2007 Open-File Report 506 updated January, 2017 New Mexico Bureau Paul W. Bauer, of Geology and Peggy S. Johnson, Mineral Resources and Stacy Timmons Big Arsenic spring i New Mexico Bureau of Geology and Mineral Resources A Division of New Mexico Institute of Mining and Technology Socorro, NM 87801 (575) 835–5490 Fax (575) 835–6333 E-mail: [email protected] ii SPRINGS OF THE RIO GRANDE GORGE, TAOS COUNTY, NEW MEXICO: INVENTORY, DATA REPORT, AND PRELIMINARY GEOCHEMISTRY Final Technical Report October 2007 Open-File Report 506 updated January, 2017 Paul W. Bauer, Peggy S. Johnson, and Stacy Timmons AQUIFER MAPPING PROGRAM New Mexico Bureau of Geology & Mineral Resources iii NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES AQUIFER MAPPING PROGRAM Project Funding Acknowledgments The Healy Foundation, with Taos County We thank Ed and Trudy Healy for funding acting as the fiscal agent. New Mexico the study through a grant from the Healy Bureau of Geology & Mineral Resources. Foundation to Taos County. The funding Bureau of Land Management, Taos Field and project planning were facilitated by Office. the efforts of Ron Gardiner (Questa), Butchie Denver (Questa), and Allen Vigil Project Personnel (former Taos Co. Planning Director). Paul Bauer, Ph.D., Principal Investigator, Greg Gustina (BLM, Taos Field Office) Principal Senior Geologist, New provided additional funding for hydrogeo- Mexico Bureau of Geology & Mineral chemical analyses in the BLM Wild Rivers Resourc es, [email protected] Recreation Area. Mark Sundin (BLM, Tasks: Project management, sampling, Taos Field Office) assisted with many aspects compilation, interpretation, technical of the project, including accompanying our report. field workers on inflatable kayak surveys Peggy Johnson, Senior Hydrogeologist, down the Ute Mountain and Taos Box sec- New Mexico Bureau of Geology & tions of the river. Del DuBois (BLM, Taos Mineral Resources Field Office) provided expert logistical sup- Tasks: Sampling, interpretation, technical port for sampling expeditions into the report. Rio Grande gorge, and assisted us with the Stacy Timmons, Senior Geologic Research river crossings. Joseph Leon and the staff of Associate, New Mexico Bureau of Geology & Mineral Resources, the BLM Wild Rivers Recreation Area pro- [email protected] vided greatly appreciated support for our Tasks: Sampling, analytical geochemistry. field work. Steve Harris, of Pilar, assisted in Brigitte Felix Kludt, GIS Specialist, New land access and sampling of several wells Mexico Bureau of Geology & Mineral in the downstream part of the study area. Resourc es, [email protected] Michael Dale (NMED DOE Oversight Tasks: Sampling, GIS, cartography, Bureau) was kind enough to provide unpub- report design, layout and production. lished data on six springs. Lewis Gillard, GIS Technician, New Mexico Bureau of Geology & Mineral Resources Tasks: Sampling, GIS, cartography. iv SPRINGS OF THE RIO GRANDE GORGE TABLE OF CONTENTS I. EXECUTIVE SUMMARY ....................................... 1 FIGURES Figure 1–Location map of the Rio Grande II. INTRODUCTION .............................................................. 2 gorge study area. .............................................................................3 Background .......................................................................................... 2 Figure 2–Generalized physiographic and Previous work .................................................................................... 2 geologic map of study area. .................................................6 Purpose and scope ........................................................................ 3 Figure 3–Photograph of the Rio Grande Description of study area ...................................................... 3 gorge showing persistent columnar jointing of basalt flows. .......................................................... 8 III. METHODOLOGY .............................................................. 4 Figure 4–Faults on the Taos Plateau inter- secting the Rio Grande gorge. ...........................................9 IV. GEOLOGIC AND HYDROLOGIC Figure 5–Index map of the Rio Grande gorge ....... SETTING ...............................................................................................5 showing the major clusters of springs. ................. 10 Regional geology ............................................................................ 5 Figure 6–Deviations in isotopic composition Previous work .................................................................................... 7 away from the meteoric water line as a result of various processes. ............................................... 15 V. SPRINGS ........................................................................................ 10 Figure 7–Graph of stable isotope data for Sunshine valley springs .........................................................10 19 Rio Grande gorge spring samples. ................... 16 Chiflo area springs .....................................................................11 Figure 8–Atmospheric concentration of Bear Crossing spring zone .................................................11 chlorofluorocarbons (CFCs). .......................................... 18 Arsenic springs ..............................................................................11 Arroyo Hondo area springs .............................................12 TABLES Taos Junction Bridge area springs .............................13 Table 1–Summary data for all inventoried Pilar area springs .........................................................................13 springs in the Rio Grande gorge ............ (10 pages) Racecourse springs ....................................................................13 Table 2–Geochemical Data for Springs ........(2 pages) VI. SPRING WATER CHEMISTRY ................. 14 APPENDIX A Spring sampling ............................................................................14 Geochemical data sheets for Rio Grande Ion chemistry ...................................................................................14 gorge spring analyses Stable isotopes................................................................................14 14 Age of ground water (Tritium, CFCs, C) ......15 PLATE 1 Detailed map of the Rio Grande gorge with REFERENCES .................................................................................. 19 locations of all springs v NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES AQUIFER MAPPING PROGRAM vi SPRINGS OF THE RIO GRANDE GORGE I. EXECUTIVE SUMMARY 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 springs in the Rio Grande gorge appear to naturally fall into zones or clusters that coin- cide with either a hydrologically important geologic feature, such as a fault or a volcano, or one of the perennial tributaries of the Rio Grande. Spring data are evaluated in the context of the regional geologic and hydrologic framework. Basic data are presented for springs surveyed in the following locations: • the Sunshine Valley in the Ute Mountain reach, • the Cerro Chiflo area, above the Cerro gaging station, • the west side of the gorge near Bear Crossing, • the Arroyo Hondo area, • Taos Junction Bridge, • Pilar, and • The Racecourse reach of the Rio Grande, between the BLM quartzite site and the county line. Water samples were collected from 31 springs and analyzed for general chemistry, trace met- als, stable isotopes, and for several relative age-dating analyses, including tritium, chlorofluoro- carbons (CFCs), and carbon-14. The report contains maps of the locations of inventoried springs, data tables that characterize the springs, the results of geochemical sampling and laboratory analysis of spring water chemistry and a variety of tracers, and a brief summary of the location and field parameters of each major cluster of springs. 1 NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES AQUIFER MAPPING PROGRAM II. INTRODUCTION in evaluating the hydrogeologic connections Background between the ground water and the river in Taos County. Future work will focus on the hydro- It has long been known that the Taos County geologic setting of the springs and ground water/ section of the Rio Grande is a gaining stream surface water interactions. (Bliss and Osgood, 1928; Spiegel and Couse, 1969; Wilson and others, 1978; Coons and Kelly, 1984; Johnson, 1998). These and other Previous Work workers have used a variety of techniques to quantify gains and losses along all or some of Although a number of workers have published the 80 river miles between the Lobatos gage and reports on some aspects of the springs in the the Embudo gage, including seepage measure- Rio Grande gorge area of Taos County, there ments, gage data, and water balances. However, has been no comprehensive inventory of the it appears that attempts to quantify the exact springs with precise locations, and no methodical locations and magnitudes of the mainstem hydrogeochemical or hydrogeologic investiga-