John F Walker (Former Employee)
Science and Products
Filter Total Items: 42
Importance of unsaturated zone flow for simulating recharge in a humid climate
Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing the same volume of water through an unsaturated zone column to the water
Authors
R. J. Hunt, David E. Prudic, J.F. Walker, M.P. Anderson
Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach
The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1 ng L
Authors
J. B. Shanley, Mast M. Alisa, K. Campbell, G. R. Aiken, D. P. Krabbenhoft, R. J. Hunt, J.F. Walker, P. F. Schuster, A. Chalmers, Brent T. Aulenbach, N.E. Peters, M. Marvin-DiPasquale, D. W. Clow, M.M. Shafer
Flood of June 2008 in Southern Wisconsin
In June 2008, heavy rain caused severe flooding across southern Wisconsin. The floods were aggravated by saturated soils that persisted from unusually wet antecedent conditions from a combination of floods in August 2007, more than 100 inches of snow in winter 2007-08, and moist conditions in spring 2008. The flooding caused immediate evacuations and road closures and prolonged, extensive damages
Authors
Faith A. Fitzpatrick, Marie C. Peppler, John F. Walker, William J. Rose, Robert J. Waschbusch, James L. Kennedy
Identifying spatial variability of groundwater discharge in a wetland stream using a distributed temperature sensor
Discrete zones of groundwater discharge in a stream within a peat‐dominated wetland were identified on the basis of variations in streambed temperature using a distributed temperature sensor (DTS). The DTS gives measurements of the spatial (±1 m) and temporal (15 min) variation of streambed temperature over a much larger reach of stream (>800 m) than previous methods. Isolated temperature anomalie
Authors
Christopher S. Lowry, John F. Walker, Randall J. Hunt, Mary P. Anderson
Dynamics of CFCs in northern temperate lakes and adjacent groundwater
Three dimictic lakes and one meromictic lake in and near the Trout Lake, Wisconsin, watershed were sampled to determine the variation of chlorofluorocarbon (CFC) concentrations within the lakes. The lakes were sampled during stratified conditions, during fall turnover, and during ice cover. The results demonstrate a considerable variation in CFC concentrations and corresponding atmospheric mixing
Authors
John F. Walker, David A. Saad, Randall J. Hunt
Water and solute mass balance of five small, relatively undisturbed watersheds in the U.S.
Geochemical mass balances were computed for water years 1992-1997 (October 1991 through September 1997) for the five watersheds of the U.S. Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) Program to determine the primary regional controls on yields of the major dissolved inorganic solutes. The sites, which vary markedly with respect to climate, geology, physiography, and ecology
Authors
N.E. Peters, J. B. Shanley, Brent T. Aulenbach, R. M. Webb, K. Campbell, R. Hunt, M. C. Larsen, R.F. Stallard, J. Troester, J.F. Walker
Measuring groundwater-surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA
Measurements of groundwater-surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes-Water, Energy and Biogeochemical Budgets (NTL-WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) s
Authors
R. J. Hunt, M. Strand, J.F. Walker
Effects of best-management practices in Otter Creek in the Sheboygan River Priority Watershed, Wisconsin, 1990-2002
The U.S. Geological Survey and the Wisconsin Department of Natural Resources began a comprehensive, multidisciplinary evaluation-monitoring program in 1989 to assess the effectiveness of the Wisconsin Nonpoint Source Program. Hydrologic, water-quality, habitat, and fish data were collected at Otter Creek from 1990 to 2002 with the pre-BMP (best-management practice) period ending in September 1993
Authors
Steven R. Corsi, John F. Walker, Lizhu Wang, Judy A. Horwatich, Roger T. Bannerman
Bridge scour monitoring methods at three sites in Wisconsin
Of the nearly 11,500 bridges in Wisconsin, 89 have been assessed with critical scour conditions. The U.S. Geological Survey, in cooperation with the Wisconsin Department of Transportation, the Marathon County Highway Department, and the Jefferson County Highway Department, performed routine monitoring of streambed elevations for three bridges. Two monitoring approaches were employed: (1) manual mo
Authors
John F. Walker, Peter E. Hughes
Variability of isotope and major ion chemistry in the Allequash Basin, Wisconsin
As part of ongoing research conducted at one of the U.S. Geological Survey's Water, Energy, and Biogeochem-ical Budgets sites, work was undertaken to describe the spatial and temporal variability of stream and ground water isotopic composition and cation chemistry in the Trout Lake watershed, to relate the variability to the watershed flow system, and to identify the linkages of geochemical evolut
Authors
John F. Walker, Randall J. Hunt, Thomas D. Bullen, David P. Krabbenhoft, Carol Kendall
Effects of best-management practices in the Black Earth Creek Priority Watershed, Wisconsin, 1984-98
The Wisconsin Department of Natural Resources and the U.S. Geological Survey began a comprehensive, multidisciplinary evaluation-monitoring program in 1989 to assess the effectiveness of the Wisconsin Nonpoint Source Program. Hydrologic and water-quality data were collected at Brewery and Garfoot Creeks in 1984 and 1985 (pre-best-management practices (BMPs) period) and 1997 and 1998 (post-BMP peri
Authors
David J. Graczyk, John F. Walker, J.A. Horwatich, Roger T. Bannerman
Flood-frequency characteristics of Wisconsin streams
Flood-frequency characteristics for 312 gaged sites on Wisconsin streams are presented for recurrence intervals of 2 to 100 years using flood-peak data collected through water year 2000. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams
Authors
John F. Walker, William R. Krug
Science and Products
Filter Total Items: 42
Importance of unsaturated zone flow for simulating recharge in a humid climate
Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing the same volume of water through an unsaturated zone column to the water
Authors
R. J. Hunt, David E. Prudic, J.F. Walker, M.P. Anderson
Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach
The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1 ng L
Authors
J. B. Shanley, Mast M. Alisa, K. Campbell, G. R. Aiken, D. P. Krabbenhoft, R. J. Hunt, J.F. Walker, P. F. Schuster, A. Chalmers, Brent T. Aulenbach, N.E. Peters, M. Marvin-DiPasquale, D. W. Clow, M.M. Shafer
Flood of June 2008 in Southern Wisconsin
In June 2008, heavy rain caused severe flooding across southern Wisconsin. The floods were aggravated by saturated soils that persisted from unusually wet antecedent conditions from a combination of floods in August 2007, more than 100 inches of snow in winter 2007-08, and moist conditions in spring 2008. The flooding caused immediate evacuations and road closures and prolonged, extensive damages
Authors
Faith A. Fitzpatrick, Marie C. Peppler, John F. Walker, William J. Rose, Robert J. Waschbusch, James L. Kennedy
Identifying spatial variability of groundwater discharge in a wetland stream using a distributed temperature sensor
Discrete zones of groundwater discharge in a stream within a peat‐dominated wetland were identified on the basis of variations in streambed temperature using a distributed temperature sensor (DTS). The DTS gives measurements of the spatial (±1 m) and temporal (15 min) variation of streambed temperature over a much larger reach of stream (>800 m) than previous methods. Isolated temperature anomalie
Authors
Christopher S. Lowry, John F. Walker, Randall J. Hunt, Mary P. Anderson
Dynamics of CFCs in northern temperate lakes and adjacent groundwater
Three dimictic lakes and one meromictic lake in and near the Trout Lake, Wisconsin, watershed were sampled to determine the variation of chlorofluorocarbon (CFC) concentrations within the lakes. The lakes were sampled during stratified conditions, during fall turnover, and during ice cover. The results demonstrate a considerable variation in CFC concentrations and corresponding atmospheric mixing
Authors
John F. Walker, David A. Saad, Randall J. Hunt
Water and solute mass balance of five small, relatively undisturbed watersheds in the U.S.
Geochemical mass balances were computed for water years 1992-1997 (October 1991 through September 1997) for the five watersheds of the U.S. Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) Program to determine the primary regional controls on yields of the major dissolved inorganic solutes. The sites, which vary markedly with respect to climate, geology, physiography, and ecology
Authors
N.E. Peters, J. B. Shanley, Brent T. Aulenbach, R. M. Webb, K. Campbell, R. Hunt, M. C. Larsen, R.F. Stallard, J. Troester, J.F. Walker
Measuring groundwater-surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA
Measurements of groundwater-surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes-Water, Energy and Biogeochemical Budgets (NTL-WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) s
Authors
R. J. Hunt, M. Strand, J.F. Walker
Effects of best-management practices in Otter Creek in the Sheboygan River Priority Watershed, Wisconsin, 1990-2002
The U.S. Geological Survey and the Wisconsin Department of Natural Resources began a comprehensive, multidisciplinary evaluation-monitoring program in 1989 to assess the effectiveness of the Wisconsin Nonpoint Source Program. Hydrologic, water-quality, habitat, and fish data were collected at Otter Creek from 1990 to 2002 with the pre-BMP (best-management practice) period ending in September 1993
Authors
Steven R. Corsi, John F. Walker, Lizhu Wang, Judy A. Horwatich, Roger T. Bannerman
Bridge scour monitoring methods at three sites in Wisconsin
Of the nearly 11,500 bridges in Wisconsin, 89 have been assessed with critical scour conditions. The U.S. Geological Survey, in cooperation with the Wisconsin Department of Transportation, the Marathon County Highway Department, and the Jefferson County Highway Department, performed routine monitoring of streambed elevations for three bridges. Two monitoring approaches were employed: (1) manual mo
Authors
John F. Walker, Peter E. Hughes
Variability of isotope and major ion chemistry in the Allequash Basin, Wisconsin
As part of ongoing research conducted at one of the U.S. Geological Survey's Water, Energy, and Biogeochem-ical Budgets sites, work was undertaken to describe the spatial and temporal variability of stream and ground water isotopic composition and cation chemistry in the Trout Lake watershed, to relate the variability to the watershed flow system, and to identify the linkages of geochemical evolut
Authors
John F. Walker, Randall J. Hunt, Thomas D. Bullen, David P. Krabbenhoft, Carol Kendall
Effects of best-management practices in the Black Earth Creek Priority Watershed, Wisconsin, 1984-98
The Wisconsin Department of Natural Resources and the U.S. Geological Survey began a comprehensive, multidisciplinary evaluation-monitoring program in 1989 to assess the effectiveness of the Wisconsin Nonpoint Source Program. Hydrologic and water-quality data were collected at Brewery and Garfoot Creeks in 1984 and 1985 (pre-best-management practices (BMPs) period) and 1997 and 1998 (post-BMP peri
Authors
David J. Graczyk, John F. Walker, J.A. Horwatich, Roger T. Bannerman
Flood-frequency characteristics of Wisconsin streams
Flood-frequency characteristics for 312 gaged sites on Wisconsin streams are presented for recurrence intervals of 2 to 100 years using flood-peak data collected through water year 2000. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams
Authors
John F. Walker, William R. Krug