Keith J Halford (Former Employee)
Science and Products
Documentation of single-well aquifer tests and integrated borehole analyses, Pahute Mesa and Vicinity, Nevada
Single-well aquifer testing has been carried out at Pahute Mesa in southern Nevada since 1962. These tests include single-well pumping and slug tests to estimate geologic formation hydraulic properties. Initially, aquifer tests focused on identifying low-permeability rocks suitable for testing large-yield nuclear devices, whereas later hydrologic...
Frus, Rebecca J.; Halford, K.J.
Evaluating micrometeorological estimates of groundwater discharge from Great Basin desert playas
Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert playas is a significant component of the groundwater budget. However, desert playa ETg rates are poorly constrained by Bowen Ratio energy budget (BREB) and eddy-covariance (EC)...
Jackson, Tracie; Halford, K.J.; Gardner, Philip M.; Garcia, Amanda
A process to estimate net infiltration using a site-scale water-budget approach, Rainier Mesa, Nevada National Security Site, Nevada, 2002–05
This report documents a process used to estimate net infiltration from precipitation, evapotranspiration (ET), and soil data acquired at two sites on Rainier Mesa. Rainier Mesa is a groundwater recharge area within the Nevada National Security Site where recharged water flows through bedrock fractures to a deep (450 meters) water table. The U.S....
Smith, David W.; Moreo, Michael T.; Garcia, C. Amanda; Halford, K.J.; Fenelon, Joseph M. Scenario Evaluator for Electrical Resistivity survey pre-modeling tool
Geophysical tools have much to offer users in environmental, water resource, and geotechnical fields; however, techniques such as electrical resistivity imaging (ERI) are often oversold and/or overinterpreted due to a lack of understanding of the limitations of the techniques, such as the appropriate depth intervals or resolution of the methods....
Terry, Neil; Day-Lewis, Frederick D.; Robinson, Judith L.; Slater, Lee D.; Halford, K.J.; Binley, Andrew; Lane, John W.; Werkema, Dale D.
Hydraulic characterization of volcanic rocks in Pahute Mesa using an integrated analysis of 16 multiple-well aquifer tests, Nevada National Security Site, 2009–14
An improved understanding of groundwater flow and radionuclide migration downgradient from underground nuclear-testing areas at Pahute Mesa, Nevada National Security Site, requires accurate subsurface hydraulic characterization. To improve conceptual models of flow and transport in the complex hydrogeologic system beneath Pahute Mesa, the U.S....
Garcia, C. Amanda; Jackson, Tracie R.; Halford, K.J.; Sweetkind, Donald S.; Damar, Nancy A.; Fenelon, Joseph M.; Reiner, Steven R. Testing the suitability of geologic frameworks for extrapolating hydraulic properties across regional scales
The suitability of geologic frameworks for extrapolating hydraulic conductivity (K) to length scales commensurate with hydraulic data is difficult to assess. A novel method is presented for evaluating assumed relations between K and geologic interpretations for regional-scale groundwater modeling. The approach relies on simultaneous...
Mirus, Benjamin B.; Halford, K.J.; Sweetkind, Donald S.; Fenelon, Joseph M.
T-COMP—A suite of programs for extracting transmissivity from MODFLOW models
Simulated transmissivities are constrained poorly by assigning permissible ranges of hydraulic conductivities from aquifer-test results to hydrogeologic units in groundwater-flow models. These wide ranges are derived from interpretations of many aquifer tests that are categorized by hydrogeologic unit. Uncertainty is added where contributing...
Halford, K.J.
Delineation of the Pahute Mesa–Oasis Valley groundwater basin, Nevada
This report delineates the Pahute Mesa–Oasis Valley (PMOV) groundwater basin, where recharge occurs, moves downgradient, and discharges to Oasis Valley, Nevada. About 5,900 acre-feet of water discharges annually from Oasis Valley, an area of springs and seeps near the town of Beatty in southern Nevada. Radionuclides in groundwater beneath Pahute...
Fenelon, Joseph M.; Halford, K.J.; Moreo, Michael T. Detecting drawdowns masked by environmental stresses with water-level models
Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations...
Garcia, C.A.; Halford, K.J.; Fenelon, J.M.
Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-in
Water-level modeling is used for multiple-well aquifer tests to reliably differentiate pumping responses from natural water-level changes in wells, or “environmental fluctuations.” Synthetic water levels are created during water-level modeling and represent the summation of multiple component fluctuations, including those caused by...
Halford, Keith; Garcia, C. Amanda; Fenelon, Joe; Mirus, Benjamin B.
The source, discharge, and chemical characteristics of water from Agua Caliente Spring, Palm Springs, California
Agua Caliente Spring, in downtown Palm Springs, California, has been used for recreation and medicinal therapy for hundreds of years and currently (2008) is the source of hot water for the Spa Resort owned by the Agua Caliente Band of the Cahuilla Indians. The Agua Caliente Spring is located about 1,500 feet east of the eastern front of the San...
Martin, Peter; Brandt, Justin; Catchings, Rufus D.; Christensen, Allen H.; Flint, Alan L.; Gandhok, Gini; Goldman, Mark R.; Halford, K.J.; Langenheim, V.E.; Martin, Peter; Rymer, Michael J.; Schroeder, Roy A.; Smith, Gregory A.; Sneed, Michelle
Assessing hydraulic connections across a complex sequence of volcanic rocks - Analysis of U-20 WW multiple-well aquifer test, Pahute Mesa, Nevada National Security Site, Nevada
Groundwater beneath Pahute Mesa flows through a complexly layered sequence of volcanic rock aquifers and confining units that have been faulted into distinct structural blocks. Hydraulic property estimates of rocks and structures in this flow system are necessary to assess radionuclide migration near underground nuclear testing areas. The U.S....
Garcia, C. Amanda; Fenelon, Joseph M.; Halford, K.J.; Reiner, Steven R.; Laczniak, Randell J.
SeriesSEE
SeriesSEE is a spreadsheet add-in for viewing time series and modeling water levels that was developed in Microsoft Excel 2010.
FLASH: A Computer Program for Flow-Log Analysis of Single Holes
FLASH (Flow-Log Analysis of Single Holes) is a computer program for the analysis of borehole vertical flow logs.
AnalyzeHOLE
AnalyzeHOLE, an integrated wellbore analysis tool for simulating flow and transport in wells and aquifer systems, provides a better alternative for simulating and evaluating complex well-aquifer system interaction.