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: 127
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
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
Sparrow modeling to understand water quality conditions in major regions of the United States: A featured collection introduction
No abstract available.
Authors
Stephen D. Preston, Richard B. Alexander, David M. Wolock
Digital hydrologic networks supporting applications related to spatially referenced regression modeling
Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents thr
Authors
John W. Brakebill, David M. Wolock, Silvia Terziotti
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 127
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
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
Sparrow modeling to understand water quality conditions in major regions of the United States: A featured collection introduction
No abstract available.
Authors
Stephen D. Preston, Richard B. Alexander, David M. Wolock
Digital hydrologic networks supporting applications related to spatially referenced regression modeling
Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents thr
Authors
John W. Brakebill, David M. Wolock, Silvia Terziotti