New Mexico Geological Society Annual Spring Meeting — Abstracts

It is important to know the chemical properties of groundwater, particularly when it is a primary source of consumed water as is the case in the Middle Rio Grande of New Mexico (MRG). Many aspects of this unique system have been studied including depth, spatial and even some temporal variability. More needs to be understood, however, about how the physical and chemical properties of groundwater in the MRG change on a temporal scale, particularly at high resolution as affected by exogenic factors. Factors such as evapotranspiration (ET) and irrigation may be affecting groundwater chemistry diurnally but cannot be quantified since there is little data to look at for correlation on such time scales.

For this study, measurements were made during baseline conditions (in winter months when ET and irrigation for agriculture were not present) of DO, conductivity, pH and water temperature for approximately one month each at three different sites along the Rio Grande using a Sonde 600 SLM (YSI) logger. These sites were chosen because they already have established 3-Dimensional Eddy Covariance systems that include several meteorological monitoring instruments as well as some for soil and water table measurements. Then the water chemistry data was analyzed and compared with the other site data to look for relationships in temporal changes of the measurements. This included comparisons of air and groundwater temperature and water chemistries to precipitation and other physical variables. The result is a baseline dataset to look at further relationships during the growing season when ET is significant and water is manipulated for anthropogenic uses.