David M Wolock, Ph.D.
David Wolock is a Supervisory Hydrologist with the USGS Water Resources Mission Area.
Science and Products
Filter Total Items: 13
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Filter Total Items: 129
An empirical approach to modeling methylmercury concentrations in an Adirondack stream watershed
Inverse empirical models can inform and improve more complex process-based models by quantifying the principal factors that control water quality variation. Here we developed a multiple regression model that explains 81% of the variation in filtered methylmercury (FMeHg) concentrations in Fishing Brook, a fourth-order stream in the Adirondack Mountains, New York, a known “hot spot” of Hg bioaccumu
Authors
Douglas A. Burns, Elizabeth A. Nystrom, David M. Wolock, Paul M. Bradley, Karen Riva-Murray
Variability common to global sea surface temperatures and runoff in the conterminous United States
Singular value decomposition (SVD) is used to identify the variability common to global sea surface temperatures (SSTs) and water-balance-modeled water-year (WY) runoff in the conterminous United States (CONUS) for the 1900–2012 period. Two modes were identified from the SVD analysis; the two modes explain 25% of the variability in WY runoff and 33% of the variability in WY SSTs. The first SVD mod
Authors
Gregory J. McCabe, David M. Wolock
Spatial and temporal patterns in conterminous United States streamflow characteristics
Spatial and temporal patterns in annual and seasonal minimum, mean, and maximum daily streamflow values were examined for a set of 516 reference stream gauges located throughout the conterminous United States for the period 1951–2009. Cluster analysis was used to classify the stream gauges into 14 groups based on similarity in their temporal patterns of streamflow. The results indicated that the t
Authors
Gregory J. McCabe, David M. Wolock
Streamflow of 2013: water year summary
The maps and graphs in this summary describe streamflow conditions for water year 2013 (October 1, 2012, to September 30, 2013) in the context of the 84-year period from 1930 through 2013, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Water Information System ( http://waterdata.usgs.gov/nwis/). The period 1930–2013 was used b
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management
Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands – the dry-subhumid, semiarid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for bo
Authors
Peter K. Weiskel, David M. Wolock, Phillip J. Zarriello, Richard M. Vogel, Sara B. Levin, Robert M. Lent
Temporal and spatial variability of global water balance
An analysis of simulated global water-balance components (precipitation [P], actual evapotranspiration [AET], runoff [R], and potential evapotranspiration [PET]) for the past century indicates that P has been the primary driver of variability in R. Additionally, since about 2000, there have been increases in P, AET, R, and PET for most of the globe. The increases in R during 2000 through 2009 have
Authors
Gregory J. McCabe, David M. Wolock
River flow changes related to land and water management practices across the conterminous United States
The effects of land and water management practices (LWMP)—such as the construction of dams and roads—on river flows typically have been studied at the scale of single river watersheds or for a single type of LWMP. For the most part, assessments of the relative effects of multiple LWMP within many river watersheds across regional and national scales have been lacking. This study assesses flow alter
Authors
Ken Eng, David M. Wolock, Daren Carlisle
Predicting the likelihood of altered streamflows at ungauged rivers across the conterminous United States
An approach is presented in this study to aid water-resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National-scale random forest statistical models are developed to predict th
Authors
Ken Eng, Daren Carlisle, David M. Wolock, James A. Falcone
Streamflow of 2012--Water Year Summary
The maps and graphs in this summary describe streamflow conditions for water year 2012 (October 1, 2011, to September 30, 2012) in the context of the 83-year period from 1930 through 2012, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930–2012 was used
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Vulnerability of streams to legacy nitrate sources
The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were
Authors
Anthony J. Tesoriero, John H. Duff, David A. Saad, Norman E. Spahr, David M. Wolock
Streamflow of 2011 - Water Year Summary
The maps and graph in this summary describe streamflow conditions for water year 2011 (October 1, 2010, to September 30, 2011) in the context of the 82-year period from 1930 through 2011, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930-2010 was used b
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Regression models for estimating concentrations of atrazine plus deethylatrazine in shallow groundwater in agricultural areas of the United States
Tobit regression models were developed to predict the summed concentration of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and its degradate deethylatrazine [6-chloro-N-(1-methylethyl)-1,3,5,-triazine-2,4-diamine] (DEA) in shallow groundwater underlying agricultural settings across the conterminous United States. The models were developed from atrazine and DEA concentr
Authors
Paul E. Stackelberg, Jack E. Barbash, Robert J. Gilliom, Wesley W. Stone, David M. Wolock
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 129
An empirical approach to modeling methylmercury concentrations in an Adirondack stream watershed
Inverse empirical models can inform and improve more complex process-based models by quantifying the principal factors that control water quality variation. Here we developed a multiple regression model that explains 81% of the variation in filtered methylmercury (FMeHg) concentrations in Fishing Brook, a fourth-order stream in the Adirondack Mountains, New York, a known “hot spot” of Hg bioaccumu
Authors
Douglas A. Burns, Elizabeth A. Nystrom, David M. Wolock, Paul M. Bradley, Karen Riva-Murray
Variability common to global sea surface temperatures and runoff in the conterminous United States
Singular value decomposition (SVD) is used to identify the variability common to global sea surface temperatures (SSTs) and water-balance-modeled water-year (WY) runoff in the conterminous United States (CONUS) for the 1900–2012 period. Two modes were identified from the SVD analysis; the two modes explain 25% of the variability in WY runoff and 33% of the variability in WY SSTs. The first SVD mod
Authors
Gregory J. McCabe, David M. Wolock
Spatial and temporal patterns in conterminous United States streamflow characteristics
Spatial and temporal patterns in annual and seasonal minimum, mean, and maximum daily streamflow values were examined for a set of 516 reference stream gauges located throughout the conterminous United States for the period 1951–2009. Cluster analysis was used to classify the stream gauges into 14 groups based on similarity in their temporal patterns of streamflow. The results indicated that the t
Authors
Gregory J. McCabe, David M. Wolock
Streamflow of 2013: water year summary
The maps and graphs in this summary describe streamflow conditions for water year 2013 (October 1, 2012, to September 30, 2013) in the context of the 84-year period from 1930 through 2013, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Water Information System ( http://waterdata.usgs.gov/nwis/). The period 1930–2013 was used b
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management
Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands – the dry-subhumid, semiarid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for bo
Authors
Peter K. Weiskel, David M. Wolock, Phillip J. Zarriello, Richard M. Vogel, Sara B. Levin, Robert M. Lent
Temporal and spatial variability of global water balance
An analysis of simulated global water-balance components (precipitation [P], actual evapotranspiration [AET], runoff [R], and potential evapotranspiration [PET]) for the past century indicates that P has been the primary driver of variability in R. Additionally, since about 2000, there have been increases in P, AET, R, and PET for most of the globe. The increases in R during 2000 through 2009 have
Authors
Gregory J. McCabe, David M. Wolock
River flow changes related to land and water management practices across the conterminous United States
The effects of land and water management practices (LWMP)—such as the construction of dams and roads—on river flows typically have been studied at the scale of single river watersheds or for a single type of LWMP. For the most part, assessments of the relative effects of multiple LWMP within many river watersheds across regional and national scales have been lacking. This study assesses flow alter
Authors
Ken Eng, David M. Wolock, Daren Carlisle
Predicting the likelihood of altered streamflows at ungauged rivers across the conterminous United States
An approach is presented in this study to aid water-resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National-scale random forest statistical models are developed to predict th
Authors
Ken Eng, Daren Carlisle, David M. Wolock, James A. Falcone
Streamflow of 2012--Water Year Summary
The maps and graphs in this summary describe streamflow conditions for water year 2012 (October 1, 2011, to September 30, 2012) in the context of the 83-year period from 1930 through 2012, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930–2012 was used
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Vulnerability of streams to legacy nitrate sources
The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were
Authors
Anthony J. Tesoriero, John H. Duff, David A. Saad, Norman E. Spahr, David M. Wolock
Streamflow of 2011 - Water Year Summary
The maps and graph in this summary describe streamflow conditions for water year 2011 (October 1, 2010, to September 30, 2011) in the context of the 82-year period from 1930 through 2011, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program (http://water.usgs.gov/nsip/). The period 1930-2010 was used b
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Regression models for estimating concentrations of atrazine plus deethylatrazine in shallow groundwater in agricultural areas of the United States
Tobit regression models were developed to predict the summed concentration of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and its degradate deethylatrazine [6-chloro-N-(1-methylethyl)-1,3,5,-triazine-2,4-diamine] (DEA) in shallow groundwater underlying agricultural settings across the conterminous United States. The models were developed from atrazine and DEA concentr
Authors
Paul E. Stackelberg, Jack E. Barbash, Robert J. Gilliom, Wesley W. Stone, David M. Wolock