Groundwater Flow and Thermal Modeling to Support a Preferred Conceptual Model for the Large Hydraulic Gradient North of Yucca Mountain

This task will create a two-dimensional, saturated zone, vertical cross-section model of groundwater flow and thermal transport through the large hydraulic gradient (LHG). This model is referenced herein as the thermal model. The scope of this study is limited to presenting a postulated hydrogeologic configuration of the LHG. The conceptualization will include the use of postulated hydrogeologic structures and material properties. The thermal model will be spatially limited to the area immediately upgradient and downgradient of the LHG and will not reproduce the many hydrogeologic features of the existing regional and site-scale models. The thermal model will be orientated north to south, approximately along a saturated zone streamline. The results of the thermal modeling will be compared to temperature data reported for site wells by the U.S. Geological Survey (USGS) and in peer-reviewed journals. Most, if not all, of this reported data is non- qualified. This task will not qualify the reported data and the reported data will be used only as a basis of comparison for the model simulations

Development of a quasi three-dimensional groundwater model for a portion of the Nevada Test Site

Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives and Public Records through the Library Services and Technology Act (LSTA). To obtain a high quality image or document please contact the DeLaMare Library at https://unr.libanswers.com/ or call: 775-784-6945.An empirical correction matrix has been devised that will partially adjust a two-dimensional model for flow in the third dimension. The correction matrix has been applied to the groundwater system from Pahute Mesa to Yucca Flat on the Nevada Test Site

Letter Report: Borehole Flow and Horizontal Hydraulic Conductivity with Depth at Well ER-12-4

Borehole flow and fluid temperature during pumping were measured at well ER-12-4 at the Nevada Test Site in Nye County, Nevada. This well was constructed to characterize the carbonate aquifer. The well is cased from land surface to the total depth at 1,132 m (3,713 ft bgs) below ground surface (bgs). The screened section of the well consists of alternating sections of slotted well screen and blank casing from 948 to 1,132 m bgs (3,111 to 3,713 ft bgs). Borehole flow velocity (LT-1) with depth was measured with an impeller flowmeter from the top of the screened section to the maximum accessible depth while the well was pumped and under ambient conditions. A complicating factor to data interpretation is that the well was not filter packed and there is upward and downward vertical flow in the open annulus under ambient and pumping conditions. The open annulus in the well casing likely causes the calculated borehole flow rates being highly nonrepresentative of inflow from the formation. Hydraulic conductivities calculated under these conditions would require unsupportable assumptions and would be subject to very large uncertainties. Borehole hydraulic conductivities are not presented under these conditions