David M Wolock, Ph.D.
David Wolock is a Supervisory Hydrologist with the USGS Water Resources Mission Area.
Science and Products
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Hydrologic landscape regions of the United States
Hydrologic landscape regions (HLRs) in the United States were delineated by using geographic information system (GIS) tools and statistical methods including principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting of 4
Authors
David M. Wolock
Saturation overland flow estimated from TOPMODEL for the conterminous United States
This 5-kilometer resolution raster (grid) dataset for the conterminous United States represents the average percentage of saturation overland flow in total streamflow estimated by the watershed model TOPMODEL. Saturation overland flow is simulated in TOPMODEL as precipitation that falls on saturated land-surface areas and enters the stream channel.
TOPMODEL was applied to 5- by 5-kilometer area
Authors
David M. Wolock
Base-Flow Index Grid for the Conterminous United States
This 1-kilometer raster (grid) dataset for the conterminous United States was created by interpolating base-flow index (BFI) values estimated at U.S. Geological Survey (USGS) streamgages. Base flow is the component of streamflow that can be attributed to ground-water discharge into streams.
Authors
David M. Wolock
Spatial and statistical differences between 1:250,000- and 1:24,000-scale digital soil databases
In this study, 1:250,000- and 1:24,000-scale digital soil databases for Kansas were compared statistically and spatially. The soil attributes used in this comparison were soil permeability, percent clay, and hydrologic group. Results indicate that, although the two databases were correlated, the potential exists for substantial site-specific variability between them. The largest differences betwee
Authors
K. E. Juracek, D. M. Wolock
Trends and temperature sensitivity of moisture conditions in the conterminous United States
Observed (1895-1999) trends in climatic moisture conditions in the conterminous United States (US) characterized by (1) annual precipitation minus annual potential evapotranspiration (PMPE), (2) annual surplus (water that eventually becomes streamflow), and (3) annual deficit (the amount of water that must be supplied by irrigation to grow vegetation at an optimum rate) are examined. The sensitivi
Authors
G.J. McCabe, D. M. Wolock
Estimates of median flows for streams on the Kansas surface water register
The Kansas State Legislature, by enacting Kansas Statute KSA 82a-2001 et. seq., mandated the criteria for determining which Kansas stream segments would be subject to classification by the State. One criterion for the selection as a classified stream segment is based on the statistic of median flow being equal to or greater than 1 cubic foot per second. As specified by KSA 82a-2001 et. seq., media
Authors
Charles A. Perry, David M. Wolock, Joshua C. Artman
A step increase in streamflow in the conterminous United States
Annual minimum, median, and maximum daily streamflow for 400 sites in the conterminous United States (U.S.), measured during 1941-1999, were examined to identify the temporal and spatial character of changes in streamflow statistics. Results indicate a noticeable increase in annual minimum and median daily streamflow around 1970, and a less significant mixed pattern of increases and decreases in a
Authors
G.J. McCabe, D. M. Wolock
Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA
Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increas
Authors
J. B. Shanley, C. Kendall, T. E. Smith, D. M. Wolock, Jeffery J. McDonnell
Differences in topographic characteristics computed from 100- and 1000-m resolution digital elevation model data
Topographic characteristics computed from 100- and 1000-m resolution digital elevation model (DEM) data are compared for 50 locations representing varied terrain in the conterminous USA. The topographic characteristics are three parameters used extensively in hydrological research and modelling - slope (S), specific catchment area (A(s)) and a wetness index computed as the logarithm of the specifi
Authors
D. M. Wolock, G.J. McCabe
Estimates of runoff using water-balance and atmospheric general circulation models
The effects of potential climate change on mean annual runoff in the conterminous United States (U.S.) are examined using a simple water-balance model and output from two atmospheric general circulation models (GCMs). The two GCMs are from the Canadian Centre for Climate Prediction and Analysis (CCC) and the Hadley Centre for Climate Prediction and Research (HAD). In general, the CCC GCM climate r
Authors
D. M. Wolock, G.J. McCabe
General-circulation-model simulations of future snowpack in the western United States
April 1 snowpack accumulations measured at 311 snow courses in the western United States (U.S.) are grouped using a correlation-based cluster analysis. A conceptual snow accumulation and melt model and monthly temperature and precipitation for each cluster are used to estimate cluster-average April 1 snowpack. The conceptual snow model is subsequently used to estimate future snowpack by using chan
Authors
G.J. McCabe, D. M. Wolock
Explaining spatial variability in mean annual runoff in the conterminous United States
The hydrologic concepts needed in a water-balance model to estimate the spatial variation in mean annual runoff for the 344 climate divisions in the conterminous United States (U.S.) were determined. The concepts that were evaluated were the climatic supply of water (precipitation), climatic demand for water (potential evapotranspiration), seasonality in supply and demand, and soil-moisture-storag
Authors
David M. Wolock, Gregory J. McCabe
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 127
Hydrologic landscape regions of the United States
Hydrologic landscape regions (HLRs) in the United States were delineated by using geographic information system (GIS) tools and statistical methods including principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting of 4
Authors
David M. Wolock
Saturation overland flow estimated from TOPMODEL for the conterminous United States
This 5-kilometer resolution raster (grid) dataset for the conterminous United States represents the average percentage of saturation overland flow in total streamflow estimated by the watershed model TOPMODEL. Saturation overland flow is simulated in TOPMODEL as precipitation that falls on saturated land-surface areas and enters the stream channel.
TOPMODEL was applied to 5- by 5-kilometer area
Authors
David M. Wolock
Base-Flow Index Grid for the Conterminous United States
This 1-kilometer raster (grid) dataset for the conterminous United States was created by interpolating base-flow index (BFI) values estimated at U.S. Geological Survey (USGS) streamgages. Base flow is the component of streamflow that can be attributed to ground-water discharge into streams.
Authors
David M. Wolock
Spatial and statistical differences between 1:250,000- and 1:24,000-scale digital soil databases
In this study, 1:250,000- and 1:24,000-scale digital soil databases for Kansas were compared statistically and spatially. The soil attributes used in this comparison were soil permeability, percent clay, and hydrologic group. Results indicate that, although the two databases were correlated, the potential exists for substantial site-specific variability between them. The largest differences betwee
Authors
K. E. Juracek, D. M. Wolock
Trends and temperature sensitivity of moisture conditions in the conterminous United States
Observed (1895-1999) trends in climatic moisture conditions in the conterminous United States (US) characterized by (1) annual precipitation minus annual potential evapotranspiration (PMPE), (2) annual surplus (water that eventually becomes streamflow), and (3) annual deficit (the amount of water that must be supplied by irrigation to grow vegetation at an optimum rate) are examined. The sensitivi
Authors
G.J. McCabe, D. M. Wolock
Estimates of median flows for streams on the Kansas surface water register
The Kansas State Legislature, by enacting Kansas Statute KSA 82a-2001 et. seq., mandated the criteria for determining which Kansas stream segments would be subject to classification by the State. One criterion for the selection as a classified stream segment is based on the statistic of median flow being equal to or greater than 1 cubic foot per second. As specified by KSA 82a-2001 et. seq., media
Authors
Charles A. Perry, David M. Wolock, Joshua C. Artman
A step increase in streamflow in the conterminous United States
Annual minimum, median, and maximum daily streamflow for 400 sites in the conterminous United States (U.S.), measured during 1941-1999, were examined to identify the temporal and spatial character of changes in streamflow statistics. Results indicate a noticeable increase in annual minimum and median daily streamflow around 1970, and a less significant mixed pattern of increases and decreases in a
Authors
G.J. McCabe, D. M. Wolock
Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA
Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increas
Authors
J. B. Shanley, C. Kendall, T. E. Smith, D. M. Wolock, Jeffery J. McDonnell
Differences in topographic characteristics computed from 100- and 1000-m resolution digital elevation model data
Topographic characteristics computed from 100- and 1000-m resolution digital elevation model (DEM) data are compared for 50 locations representing varied terrain in the conterminous USA. The topographic characteristics are three parameters used extensively in hydrological research and modelling - slope (S), specific catchment area (A(s)) and a wetness index computed as the logarithm of the specifi
Authors
D. M. Wolock, G.J. McCabe
Estimates of runoff using water-balance and atmospheric general circulation models
The effects of potential climate change on mean annual runoff in the conterminous United States (U.S.) are examined using a simple water-balance model and output from two atmospheric general circulation models (GCMs). The two GCMs are from the Canadian Centre for Climate Prediction and Analysis (CCC) and the Hadley Centre for Climate Prediction and Research (HAD). In general, the CCC GCM climate r
Authors
D. M. Wolock, G.J. McCabe
General-circulation-model simulations of future snowpack in the western United States
April 1 snowpack accumulations measured at 311 snow courses in the western United States (U.S.) are grouped using a correlation-based cluster analysis. A conceptual snow accumulation and melt model and monthly temperature and precipitation for each cluster are used to estimate cluster-average April 1 snowpack. The conceptual snow model is subsequently used to estimate future snowpack by using chan
Authors
G.J. McCabe, D. M. Wolock
Explaining spatial variability in mean annual runoff in the conterminous United States
The hydrologic concepts needed in a water-balance model to estimate the spatial variation in mean annual runoff for the 344 climate divisions in the conterminous United States (U.S.) were determined. The concepts that were evaluated were the climatic supply of water (precipitation), climatic demand for water (potential evapotranspiration), seasonality in supply and demand, and soil-moisture-storag
Authors
David M. Wolock, Gregory J. McCabe