title: Interpreting Variations in Groundwater Flows from Repeated Distributed Thermal Perturbation Tests.
abstract: To better understand the groundwater resources of southern Nye County, Nevada, a multipart distributed thermal perturbation sensing (DTPS) test was performed on a complex of three wells. These wells penetrate an alluvial aquifer that drains the Nevada National Security Site, and characterizing the hydraulic properties and flow paths of the regional groundwater flow system has proven very difficult. The well complex comprised one pumping well and two observation wells, both located 18 m from the pumping well. Using fiber-optic cables and line heaters, DTPS tests were performed under both stressed and unstressed conditions. Each test injects heat into the water column over a period of one to two days, and observes the rising temperature during heat injection and falling temperatures after heating ceases. Aquifer thermal properties are inferred from temperature patterns in the cased section of the wells, and fluxes through the 30-m screened section are estimated based on a model that incorporates conductive and advective heat fluxes. Vertical variations in flux are examined on a scale of tens of cm. The actively flowing zones of the aquifer change between the stressed and unstressed test, and anisotropy in the aquifer permeability is apparent from the changing fluxes between tests. The fluxes inferred from the DTPS tests are compared to solute tracer tests previously performed on the same site. The DTPS-based fluxes are consistent with the fastest solute transport observed in the tracer test, but appear to overestimate the mean flux through the system.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Hausner
authors.affiliation: Nuclear Waste Repository Program Office, Nye County, Pahrump, NV, 89048.|Currently at Drilling Regulations and Adjudications, Nevada Division of Water Resources, Carson City, NV, 89701.
authors.forename: Levi
authors.initials: L
authors.lastname: Kryder
authors.affiliation: Nuclear Waste Repository Program Office, Nye County, Pahrump, NV, 89048.
authors.forename: John
authors.initials: J
authors.lastname: Klenke
authors.affiliation: Norwest Corporation, Denver, CO, 80246.
authors.forename: Richard
authors.initials: R
authors.lastname: Reinke
authors.affiliation: Department of Geological Sciences and Engineering, University of Nevada, Reno, NV, 89557.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Tyler
mesh_terms: D004784:Environmental Monitoring; D060587:Groundwater; D008962:Models, Theoretical; D009505:Nevada; D014872:Water Movements; D060986:Water Wells