Publications
Dive into our publications and explore the science from the Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology).
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Deformation-induced changes in hydraulic head during ground-water withdrawal
Ground-water withdrawal from a confined or semiconfined aquifer causes three-dimensional deformation in the pumped aquifer and in adjacent layers (overlying and underlying aquifers and aquitards). In response to the deformation, hydraulic head in the adjacent layers could rise or fall almost immediately after the start of pumping. This deformation-induced effect suggest that an adjacent layer unde
Authors
Paul A. Hsieh
Multiport well design for sampling of ground water at closely spaced vertical intervals
Detailed vertical sampling is useful in aquifers where vertical mixing is limited and steep vertical gradients in chemical concentrations are expected. Samples can be collected at closely spaced vertical intervals from nested wells with short screened intervals. However, this approach may not be appropriate in all situations. An easy-to-construct and easy-to-install multiport sampling well to coll
Authors
G. N. Delin, M.K. Landon
Denitrification and mixing in a stream-aquifer system: Effects on nitrate loading to surface water
Ground water in terrace deposits of the South Platte River alluvial aquifer near Greeley, Colorado, USA, had a median nitrate concentration of 1857 μmol l−1. Median nitrate concentrations in ground water from adjacent floodplain deposits (468 μmol l−1) and riverbed sediments (461 μmol l−1), both of which are downgradient from the terrace deposits, were lower than the median concentration in the te
Authors
P. B. McMahon, J.K. Böhlke
Chloride mass-balance method for estimating ground water recharge in arid areas: Examples from western Saudi Arabia
The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in regional aquifers in semi-arid areas. Because the method integrates recharge in tim
Authors
A.S. Bazuhair, W.W. Wood
The use of streambed temperature profiles to estimate the depth, duration, and rate of percolation beneath arroyos
Temporal variations in a streambed temperature profile between 30 and 300 cm beneath Tijeras Arroyo, New Mexico, were analyzed at 30-min intervals for 1990 to estimate the depth, duration, and rate of percolation during streamflows. The depth of percolation was clearly documented by the rapid response of the streambed temperature profile to streamflows. Results indicate that the streambed possesse
Authors
James Constantz, Carole L. Thomas
The combined use of 87Sr/86Sr and carbon and water isotopes to study the hydrochemical interaction between groundwater and lakewater in mantled karst
The hydrochemical interaction between groundwater and lakewater influences the composition of water that percolates downward from the surficial aquifer system through the underlying intermediate confining unit and recharges the Upper Floridan aquifer along highlands in Florida. The 87Sr/86Sr ratio along with the stable isotopes, D, 18O, and 13C were used as tracers to study the interaction between
Authors
B. G. Katz, T.D. Bullen
Documentation of computer program VS2Dh for simulation of energy transport in variably saturated porous media: Modification of the US Geological Survey's computer program VS2DT
No abstract available.
Authors
R. W. Healy, A.D. Ronan
Hydrogeology and geochemistry of acid mine drainage in ground water in the vicinity of Penn Mine and Camanche Reservoir, Calaveras County, California: Second-year summary, 1992-93
No abstract available.
Authors
Scott N. Hamlin, Charles N. Alpers
Hydrogeology and simulation of ground-water flow, Picatinny Arsenal and vicinity, Morris County, New Jersey
Ground-water flow in glacial sediments and bedrock at Picatinny Arsenal, N.J., was simulated by use of a three-dimensional finite-difference ground- water-flow model. The modeled area includes a 4.3-square-mile area that extends from Picatinny Lake to the Rockaway River. Most of the study area is bounded by the natural hydrologic boundaries of the ground-water system. eophysical logs, lithologic l
Authors
L. M. Voronin, D.E. Rice
Water-quality data for nutrients, pesticides, and volatile organic compounds in near-surface aquifers of the midcontinental United States, 1992-1994
Water samples were collected from 175 wells in 12 Midcontinental States (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin) from 1992 through 1994 to determine the spatial distribution of nutrients, pesticides, and volatile organic compounds in ground water, and to document the potential effects of the historic flooding that occur
Authors
D.W. Kolpin, K.E. Zichelle, E.M. Thurman
The deethylatrazine/atrazine ratio as an indicator of the onset of the spring flush of herbicides into surface water of the Midwestern United States
The ratio of deethylatrazine to atrazine (DAR) may be used to record the first major runoff of herbicides from non-point-source corn fields to surface water in the Midwestern United States. The DAR dramatically decreases from ∼0.5 to < 0.1 upon application of herbicide and the first major runoff event of a basin. The DAR then gradually increases to values of approximately 0.4–0.6 during the harves
Authors
E.M. Thurman, J. D. Fallon
Acetochlor in the hydrologic system in the midwestern United States, 1994
The herbicide acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide] was given conditional registration in the United States by the U.S. Environmental Protection Agency in March 1994. This registration provided a rare opportunity to investigate the occurrence of a pesticide during its first season of extensive use in the midwestern United States. Water samples collected and ana
Authors
D.W. Kolpin, B.K. Nations, D. A. Goolsby, E.M. Thurman