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2007 Ground Water Summit |
Monday, April 30, 2007 : 2:20 p.m.
Hydrogeologic Influences on Surface Water Salinization in the Lower Rio Grande Valley, New Mexico
Water quality in the Lower Rio Grande (LRG) Valley (San Marcial, NM, to El Paso, TX) has been extensively studied and observed salinization has been attributed to various mechanisms, including agricultural practices and inflow of deep saline and geothermal groundwater. We evaluate historical chloride and streamflow data (1905 to 2003), review previous investigations, and consider the most recent hydrogeologic interpretations of the study area (including Palomas, Mesilla, and Jornada del Muerto Basins). Based on the conceptual model of the system, we identified the various sources of water and, therefore, salinity to the LRG and designed a sampling plan to characterize these sources. Finally, we conducted two synoptic sampling events to test for geochemical and environmental tracers. Results of geochemical and isotopic analyses and a chloride mass balance assessment confirm that natural sources of salinity are the principal contributors to the salinization of the Rio Grande. Specifically, a combination of geothermal and deep saline groundwater inflow to the Rio Grande is primarily responsible for the observed salinization of the LRG. These analyses indicate that it is not possible to reproduce the observed salinization by evapotranspiration and agricultural processes alone.
Stephanie J. Moore, Daniel B. Stephens & Associates Inc. Stephanie Moore is a Hydrologist with Daniel B. Stephens & Associates. She spent eight years with the U.S. Geological Survey before joining DBS&A in early 2005. She holds a B.S. degree in Environmental Science and an M.S. degree in Earth and Planetary Sciences. Stephanie’s key areas of expertise include quantitative analysis of stream-aquifer interactions, vadose-zone processes, and spatial and temporal variations in water quality. She has successfully managed a variety of hydrogeologic investigations throughout New Mexico, including several comprehensive water quality studies. Ms. Moore has authored and co-authored several peer-reviewed papers and reports.