CHEMICAL EVOLUTION OF GROUNDWATER IN THE AMARGOSA DESERT

The present Study, as part of the Nye County Independent Scientific Investigation Program (ISIP), will attempt to provide a new insight into the chemical evolution of southern Nevada’s groundwater and its potential flow paths and rates during the infiltration and surface runoff processes. A surface runoff sampling network was initiated to track the chemical footprint of the surface runoff water as it infiltrates and recharges the groundwater. A data baseline was collected through a long term study on a comprehensive suite of chemical parameters obtained by the network of Surface Runoff Samples (SRS); parameters studied include the major ion chemistry, nutrients, trace elements, as well as stable isotope. Multiple analytical methods will be performed to analyses these data and to develop a defensible groundwater chemistry monitoring network, down-gradient of Yucca Mountain, suitable for long-term performance confirmation monitoring.

This study will include precipitation water chemistry, surface water runoff chemistry, soil chemistry, and groundwater chemistry in the study area. The field and experimental work will collect the required chemical data for the precipitation water, surface water runoff and sediment analysis. According to this plan, new methods were developed to control the construction and emplacement of SRS in addition to the collection, field testing, and handling of precipitation water samples, surface runoff water samples, and sediment samples from the time the samples are gathered at the location until they are ready to be sent to the laboratory for chemical analysis. Different analytical methods, mapping, and modeling techniques will be performed to achieve the main goals of this research.

We explain the design and emplacement of 56 surface runoff samplers at 28 different locations and provide a look at initial data collection. We believe that long term data collection of this type will help to better understand processes controlling groundwater recharge through surface runoff at arroyos and thus the sustainable yield of groundwater in Nye County.