Leon Kauffman
Scientist for the USGS New Jersey Water Science Center.
Science and Products
Modeling long-term trends of chlorinated ethene contamination at a public supply well
A mass-balance solute-transport modeling approach was used to investigate the effects of dense nonaqueous phase liquid (DNAPL) volume, composition, and generation of daughter products on simulated and measured long-term trends of chlorinated ethene (CE) concentrations at a public supply well. The model was built by telescoping a calibrated regional three-dimensional MODFLOW model to the capture zo
Authors
Francis H. Chapelle, Leon J. Kauffman, Mark A. Widdowson
Modeling the effects of naturally occurring organic carbon on chlorinated ethene transport to a public supply well
The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by t
Authors
Francis H. Chapelle, Leon J. Kauffman, Mark A. Widdowson
On modeling weak sinks in MODPATH
Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to p
Authors
Daniel B. Abrams, Henk Haitjema, Leon J. Kauffman
Use of an integrated flow model to estimate ecologically relevant hydrologic characteristics at stream biomonitoring sites
We developed an integrated hydroecological model to provide a comprehensive set of hydrologic variables representing five major components of the flow regime at 856 aquatic-invertebrate monitoring sites in New Jersey. The hydroecological model simulates streamflow by routing water that moves overland and through the subsurface from atmospheric delivery to the watershed outlet. Snow accumulation an
Authors
J.G. Kennen, L. J. Kauffman, M. A. Ayers, D. M. Wolock, Susan J. Colarullo
Mercury concentrations in water from an unconfined aquifer system, New Jersey coastal plain
Concentrations of total mercury (Hg) from 2 μg/L (the USEPA maximum contaminant level) to 72 μg/L in water from about 600 domestic wells in residential parts of eight counties in southern New Jersey have been reported by State and county agencies. The wells draw water from the areally extensive (7770 km2) unconfined Kirkwood–Cohansey aquifer system, in which background concentrations of Hg are abo
Authors
J. L. Barringer, Zoltan Szabo, L. J. Kauffman, T. H. Barringer, P. E. Stackelberg, T. Ivahnenko, S. Rajagopalan, D. P. Krabbenhoft
Application of health-based screening levels to ground-water quality data in a state-scale pilot effort
A state-scale pilot effort was conducted to evaluate a Health-Based Screening Level (HBSL) approach developed for communicating findings from the U.S. Geological Survey (USGS) National Water-Quality Assessment Program in a human-health context. Many aquifers sampled by USGS are used as drinking-water sources, and water-quality conditions historically have been assessed by comparing measured contam
Authors
Patricia L. Toccalino, Julia E. Norman, Robyn H. Phillips, Leon J. Kauffman, Paul E. Stackelberg, Lisa H. Nowell, Sandra J. Krietzman, Gloria B. Post
Estimating spatial variability of recharge in southern New Jersey from unsaturated-zone measurements
Spatial variability of recharge in southern New Jersey was studied by sampling the unsat-urated zone at 48 sites distributed over approximately 930 square kilometers. Samples of unsaturated-zone sediment were collected during the summer and fall of 1996. Unsaturated flow was calculated using moisture-content data and estimates of conductivity and matric potential derived from sediment-size data. M
Authors
Arthur L. Baehr, Leon J. Kauffman, Kimberlie Perkins, Bernard T. Nolan
Spatial variability of groundwater recharge and its effect on shallow groundwater quality in southern New Jersey
Point estimates of groundwater recharge at 48 sediment-coring locations vary substantially (−18.5–1840 cm yr−1) in a 930-km2 area of southern New Jersey. Darcian estimates of steady, long-term recharge made at depth in the unsaturated zone were estimated using pedotransfer functions of soil texture and interpolated (mapped) with nonparametric methods to assess aquifer vulnerability in the area. Th
Authors
Bernard T. Nolan, Arthur L. Baehr, Leon J. Kauffman
Effects of land use and travel time on the distribution of nitrate in the Kirkwood-Cohansey aquifer system in southern New Jersey
Residents of the southern New Jersey Coastal Plain are increasingly reliant on the unconfined Kirkwood-Cohansey aquifer system for public water supply as a result of increasing population and restrictions on withdrawals from the deeper, confined aquifers. Elevated nitrate concentrations above background levels have been found in wells in the surficial aquifer system in agricultural and urban parts
Authors
Leon J. Kauffman, Arthur L. Baehr, Mark A. Ayers, Paul E. Stackelberg
Water quality data for selected wells in the Coastal Plain of New Jersey, 1996-98
Water-quality data were collected during 1996-98 for 217 wells in New Jersey and 3 wells in New York as part of the U. S. Geological Survey's National Water Quality Assessment Program. Samples were collected for five ground-water surveys that were designed to assess water quality in major aquifer systems, with an emphasis on recently recharged (shallow) ground water associated with present and rec
Authors
Kathleen L. Hibbs, Paul E. Stackelberg, Leon J. Kauffman, Mark A. Ayers
Comparison of nitrate, pesticides, and volatile organic compounds in samples from monitoring and public-supply wells, Kirkwood-Cohansey aquifer system, southern New Jersey
The number and total concentration of
volatile organic compounds (VOCs) per
sample were significantly greater in water from
public-supply wells than in water from shallow
and moderate-depth monitoring wells in the
surficial Kirkwood-Cohansey aquifer system in
the Glassboro area of southern New Jersey. In
contrast, concentrations of nitrate (as nitrogen)
and the number and total concentrati
Authors
Paul E. Stackelberg, L. J. Kauffman, A. L. Baehr, M. A. Ayers
Occurrence of nitrate, pesticides, and volatile organic compounds in the Kirkwood-Cohansey aquifer system, southern New Jersey
Water samples were collected from a network of 72 shallow monitoring wells to assess the chemical quality of recently recharged ground water in the surficial Kirkwood- Cohansey aquifer system of southern New Jersey. The wells are randomly distributed among agricultural, urban, and undeveloped areas to provide data representative of chemical conditions of ground water underlying each of these land-
Authors
Paul E. Stackelberg, Jessica A. Hopple, Leon J. Kauffman
MODPATH Observation Process (MODPATH-OBS)
The MODPATH-OBS (Hanson and others, 2013) computer program is designed to calculate simulated equivalents for observations related to advective groundwater transport that can be represented in a quantitative way by using simulated particle-tracking data.
Science and Products
- Publications
Modeling long-term trends of chlorinated ethene contamination at a public supply well
A mass-balance solute-transport modeling approach was used to investigate the effects of dense nonaqueous phase liquid (DNAPL) volume, composition, and generation of daughter products on simulated and measured long-term trends of chlorinated ethene (CE) concentrations at a public supply well. The model was built by telescoping a calibrated regional three-dimensional MODFLOW model to the capture zoAuthorsFrancis H. Chapelle, Leon J. Kauffman, Mark A. WiddowsonModeling the effects of naturally occurring organic carbon on chlorinated ethene transport to a public supply well
The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by tAuthorsFrancis H. Chapelle, Leon J. Kauffman, Mark A. WiddowsonOn modeling weak sinks in MODPATH
Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to pAuthorsDaniel B. Abrams, Henk Haitjema, Leon J. KauffmanUse of an integrated flow model to estimate ecologically relevant hydrologic characteristics at stream biomonitoring sites
We developed an integrated hydroecological model to provide a comprehensive set of hydrologic variables representing five major components of the flow regime at 856 aquatic-invertebrate monitoring sites in New Jersey. The hydroecological model simulates streamflow by routing water that moves overland and through the subsurface from atmospheric delivery to the watershed outlet. Snow accumulation anAuthorsJ.G. Kennen, L. J. Kauffman, M. A. Ayers, D. M. Wolock, Susan J. ColarulloMercury concentrations in water from an unconfined aquifer system, New Jersey coastal plain
Concentrations of total mercury (Hg) from 2 μg/L (the USEPA maximum contaminant level) to 72 μg/L in water from about 600 domestic wells in residential parts of eight counties in southern New Jersey have been reported by State and county agencies. The wells draw water from the areally extensive (7770 km2) unconfined Kirkwood–Cohansey aquifer system, in which background concentrations of Hg are aboAuthorsJ. L. Barringer, Zoltan Szabo, L. J. Kauffman, T. H. Barringer, P. E. Stackelberg, T. Ivahnenko, S. Rajagopalan, D. P. KrabbenhoftApplication of health-based screening levels to ground-water quality data in a state-scale pilot effort
A state-scale pilot effort was conducted to evaluate a Health-Based Screening Level (HBSL) approach developed for communicating findings from the U.S. Geological Survey (USGS) National Water-Quality Assessment Program in a human-health context. Many aquifers sampled by USGS are used as drinking-water sources, and water-quality conditions historically have been assessed by comparing measured contamAuthorsPatricia L. Toccalino, Julia E. Norman, Robyn H. Phillips, Leon J. Kauffman, Paul E. Stackelberg, Lisa H. Nowell, Sandra J. Krietzman, Gloria B. PostEstimating spatial variability of recharge in southern New Jersey from unsaturated-zone measurements
Spatial variability of recharge in southern New Jersey was studied by sampling the unsat-urated zone at 48 sites distributed over approximately 930 square kilometers. Samples of unsaturated-zone sediment were collected during the summer and fall of 1996. Unsaturated flow was calculated using moisture-content data and estimates of conductivity and matric potential derived from sediment-size data. MAuthorsArthur L. Baehr, Leon J. Kauffman, Kimberlie Perkins, Bernard T. NolanSpatial variability of groundwater recharge and its effect on shallow groundwater quality in southern New Jersey
Point estimates of groundwater recharge at 48 sediment-coring locations vary substantially (−18.5–1840 cm yr−1) in a 930-km2 area of southern New Jersey. Darcian estimates of steady, long-term recharge made at depth in the unsaturated zone were estimated using pedotransfer functions of soil texture and interpolated (mapped) with nonparametric methods to assess aquifer vulnerability in the area. ThAuthorsBernard T. Nolan, Arthur L. Baehr, Leon J. KauffmanEffects of land use and travel time on the distribution of nitrate in the Kirkwood-Cohansey aquifer system in southern New Jersey
Residents of the southern New Jersey Coastal Plain are increasingly reliant on the unconfined Kirkwood-Cohansey aquifer system for public water supply as a result of increasing population and restrictions on withdrawals from the deeper, confined aquifers. Elevated nitrate concentrations above background levels have been found in wells in the surficial aquifer system in agricultural and urban partsAuthorsLeon J. Kauffman, Arthur L. Baehr, Mark A. Ayers, Paul E. StackelbergWater quality data for selected wells in the Coastal Plain of New Jersey, 1996-98
Water-quality data were collected during 1996-98 for 217 wells in New Jersey and 3 wells in New York as part of the U. S. Geological Survey's National Water Quality Assessment Program. Samples were collected for five ground-water surveys that were designed to assess water quality in major aquifer systems, with an emphasis on recently recharged (shallow) ground water associated with present and recAuthorsKathleen L. Hibbs, Paul E. Stackelberg, Leon J. Kauffman, Mark A. AyersComparison of nitrate, pesticides, and volatile organic compounds in samples from monitoring and public-supply wells, Kirkwood-Cohansey aquifer system, southern New Jersey
The number and total concentration of volatile organic compounds (VOCs) per sample were significantly greater in water from public-supply wells than in water from shallow and moderate-depth monitoring wells in the surficial Kirkwood-Cohansey aquifer system in the Glassboro area of southern New Jersey. In contrast, concentrations of nitrate (as nitrogen) and the number and total concentratiAuthorsPaul E. Stackelberg, L. J. Kauffman, A. L. Baehr, M. A. AyersOccurrence of nitrate, pesticides, and volatile organic compounds in the Kirkwood-Cohansey aquifer system, southern New Jersey
Water samples were collected from a network of 72 shallow monitoring wells to assess the chemical quality of recently recharged ground water in the surficial Kirkwood- Cohansey aquifer system of southern New Jersey. The wells are randomly distributed among agricultural, urban, and undeveloped areas to provide data representative of chemical conditions of ground water underlying each of these land-AuthorsPaul E. Stackelberg, Jessica A. Hopple, Leon J. Kauffman - Software
MODPATH Observation Process (MODPATH-OBS)
The MODPATH-OBS (Hanson and others, 2013) computer program is designed to calculate simulated equivalents for observations related to advective groundwater transport that can be represented in a quantitative way by using simulated particle-tracking data.