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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Streamflow of 2016—Water year summary
The maps and graphs in this summary describe national streamflow conditions for water year 2016 (October 1, 2015, to September 30, 2016) in the context of streamflow ranks relative to the 87-year period of 1930–2016, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Network. The period of 1930–2016 was used because the
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steven J. Brady
Variability of runoff-based drought conditions in the conterminous United States
In this study, a monthly water-balance model is used to simulate monthly runoff for 2109 hydrologic units (HUs) in the conterminous United States (CONUS) for water-years 1901 through 2014. The monthly runoff time series for each HU were smoothed with a 3-month moving average, and then the 3-month moving-average runoff values were converted to percentiles. For each HU, a drought was considered to o
Authors
Gregory J. McCabe, David M. Wolock, Samuel H. Austin
Estimating natural monthly streamflows in California and the likelihood of anthropogenic modification
Because natural patterns of streamflow are a fundamental property of the health of streams, there is a critical need to quantify the degree to which human activities have modified natural streamflows. A requirement for assessing streamflow modification in a given stream is a reliable estimate of flows expected in the absence of human influences. Although there are many techniques to predict stream
Authors
Daren Carlisle, David M. Wolock, Jeanette K. Howard, Theodore E. Grantham, Kurt Fesenmyer, Michael Wieczorek
Streamflow of 2015—Water year national summary
IntroductionThe maps and graphs in this summary describe national streamflow conditions for water year 2015 (October 1, 2014, to September 30, 2015) in the context of the 86-year period 1930–2015, 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 1930–2015 was
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Variability and trends in runoff efficiency in the conterminous United States
Variability and trends in water-year runoff efficiency (RE) — computed as the ratio of water-year runoff (streamflow per unit area) to water-year precipitation — in the conterminous United States (CONUS) are examined for the 1951 through 2012 period. Changes in RE are analyzed using runoff and precipitation data aggregated to United States Geological Survey 8-digit hydrologic cataloging units (HUs
Authors
Gregory J. McCabe, David M. Wolock
By
Hydrologic implications of GRACE satellite data in the Colorado River Basin
Use of GRACE (Gravity Recovery and Climate Experiment) satellites for assessing global water resources is rapidly expanding. Here we advance application of GRACE satellites by reconstructing long-term total water storage (TWS) changes from ground-based monitoring and modeling data. We applied the approach to the Colorado River Basin which has experienced multiyear intense droughts at decadal inter
Authors
Bridget R. Scanlon, Zizhan Zhang, Robert C. Reedy, Donald R. Pool, Himanshu Save, Di Long, Jianli Chen, David M. Wolock, Brian D. Conway, Daniel Winester
Increasing Northern Hemisphere water deficit
A monthly water-balance model is used with CRUTS3.1 gridded monthly precipitation and potential evapotranspiration (PET) data to examine changes in global water deficit (PET minus actual evapotranspiration) for the Northern Hemisphere (NH) for the years 1905 through 2009. Results show that NH deficit increased dramatically near the year 2000 during both the cool (October through March) and warm (A
Authors
Gregory J. McCabe, David M. Wolock
Sensitivity of intermittent streams to climate variations in the USA
There is a great deal of interest in the literature on streamflow changes caused by climate change because of the potential negative effects on aquatic biota and water supplies. Most previous studies have primarily focused on perennial streams, and there have been only a few studies examining the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identi
Authors
Ken Eng, David M. Wolock, Mike Dettinger
Variability and trends in global drought
Monthly precipitation (P) and potential evapotranspiration (PET) from the CRUTS3.1 data set are used to compute monthly P minus PET (PMPE) for the land areas of the globe. The percent of the global land area with annual sums of PMPE less than zero are used as an index of global drought (%drought) for 1901 through 2009. Results indicate that for the past century %drought has not changed, even thoug
Authors
Gregory J. McCabe, David M. Wolock
Streamflow of 2014: water year summary
The maps and graphs in this summary describe streamflow conditions for water year 2014 (October 1, 2013, to September 30, 2014) in the context of the 85-year period from 1930 through 2014, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program (NSIP) (http://water.usgs.gov/nsip/). The period 1930–2014 wa
Authors
Xiaodong Jian, David M. Wolock, Harry L. Jenter, Steve Brady
A new approach for continuous estimation of baseflow using discrete water quality data: Method description and comparison with baseflow estimates from two existing approaches
Understanding how watershed characteristics and climate influence the baseflow component of stream discharge is a topic of interest to both the scientific and water management communities. Therefore, the development of baseflow estimation methods is a topic of active research. Previous studies have demonstrated that graphical hydrograph separation (GHS) and conductivity mass balance (CMB) methods
Authors
Matthew P. Miller, Henry M. Johnson, David D. Susong, David M. Wolock
An objective and parsimonious approach for classifying natural flow regimes at a continental scale
Hydro-ecological stream classification-the process of grouping streams by similar hydrologic responses and, by extension, similar aquatic habitat-has been widely accepted and is considered by some to be one of the first steps towards developing ecological flow targets. A new classification of 1543 streamgauges in the contiguous USA is presented by use of a novel and parsimonious approach to unders
Authors
Stacey A. Archfield, Jonathan Kennen, Daren Carlisle, David M. Wolock
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 129
Streamflow of 2016—Water year summary
The maps and graphs in this summary describe national streamflow conditions for water year 2016 (October 1, 2015, to September 30, 2016) in the context of streamflow ranks relative to the 87-year period of 1930–2016, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Network. The period of 1930–2016 was used because the
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steven J. Brady
Variability of runoff-based drought conditions in the conterminous United States
In this study, a monthly water-balance model is used to simulate monthly runoff for 2109 hydrologic units (HUs) in the conterminous United States (CONUS) for water-years 1901 through 2014. The monthly runoff time series for each HU were smoothed with a 3-month moving average, and then the 3-month moving-average runoff values were converted to percentiles. For each HU, a drought was considered to o
Authors
Gregory J. McCabe, David M. Wolock, Samuel H. Austin
Estimating natural monthly streamflows in California and the likelihood of anthropogenic modification
Because natural patterns of streamflow are a fundamental property of the health of streams, there is a critical need to quantify the degree to which human activities have modified natural streamflows. A requirement for assessing streamflow modification in a given stream is a reliable estimate of flows expected in the absence of human influences. Although there are many techniques to predict stream
Authors
Daren Carlisle, David M. Wolock, Jeanette K. Howard, Theodore E. Grantham, Kurt Fesenmyer, Michael Wieczorek
Streamflow of 2015—Water year national summary
IntroductionThe maps and graphs in this summary describe national streamflow conditions for water year 2015 (October 1, 2014, to September 30, 2015) in the context of the 86-year period 1930–2015, 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 1930–2015 was
Authors
Xiaodong Jian, David M. Wolock, Harry F. Lins, Steve Brady
Variability and trends in runoff efficiency in the conterminous United States
Variability and trends in water-year runoff efficiency (RE) — computed as the ratio of water-year runoff (streamflow per unit area) to water-year precipitation — in the conterminous United States (CONUS) are examined for the 1951 through 2012 period. Changes in RE are analyzed using runoff and precipitation data aggregated to United States Geological Survey 8-digit hydrologic cataloging units (HUs
Authors
Gregory J. McCabe, David M. Wolock
By
Hydrologic implications of GRACE satellite data in the Colorado River Basin
Use of GRACE (Gravity Recovery and Climate Experiment) satellites for assessing global water resources is rapidly expanding. Here we advance application of GRACE satellites by reconstructing long-term total water storage (TWS) changes from ground-based monitoring and modeling data. We applied the approach to the Colorado River Basin which has experienced multiyear intense droughts at decadal inter
Authors
Bridget R. Scanlon, Zizhan Zhang, Robert C. Reedy, Donald R. Pool, Himanshu Save, Di Long, Jianli Chen, David M. Wolock, Brian D. Conway, Daniel Winester
Increasing Northern Hemisphere water deficit
A monthly water-balance model is used with CRUTS3.1 gridded monthly precipitation and potential evapotranspiration (PET) data to examine changes in global water deficit (PET minus actual evapotranspiration) for the Northern Hemisphere (NH) for the years 1905 through 2009. Results show that NH deficit increased dramatically near the year 2000 during both the cool (October through March) and warm (A
Authors
Gregory J. McCabe, David M. Wolock
Sensitivity of intermittent streams to climate variations in the USA
There is a great deal of interest in the literature on streamflow changes caused by climate change because of the potential negative effects on aquatic biota and water supplies. Most previous studies have primarily focused on perennial streams, and there have been only a few studies examining the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identi
Authors
Ken Eng, David M. Wolock, Mike Dettinger
Variability and trends in global drought
Monthly precipitation (P) and potential evapotranspiration (PET) from the CRUTS3.1 data set are used to compute monthly P minus PET (PMPE) for the land areas of the globe. The percent of the global land area with annual sums of PMPE less than zero are used as an index of global drought (%drought) for 1901 through 2009. Results indicate that for the past century %drought has not changed, even thoug
Authors
Gregory J. McCabe, David M. Wolock
Streamflow of 2014: water year summary
The maps and graphs in this summary describe streamflow conditions for water year 2014 (October 1, 2013, to September 30, 2014) in the context of the 85-year period from 1930 through 2014, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow Information Program (NSIP) (http://water.usgs.gov/nsip/). The period 1930–2014 wa
Authors
Xiaodong Jian, David M. Wolock, Harry L. Jenter, Steve Brady
A new approach for continuous estimation of baseflow using discrete water quality data: Method description and comparison with baseflow estimates from two existing approaches
Understanding how watershed characteristics and climate influence the baseflow component of stream discharge is a topic of interest to both the scientific and water management communities. Therefore, the development of baseflow estimation methods is a topic of active research. Previous studies have demonstrated that graphical hydrograph separation (GHS) and conductivity mass balance (CMB) methods
Authors
Matthew P. Miller, Henry M. Johnson, David D. Susong, David M. Wolock
An objective and parsimonious approach for classifying natural flow regimes at a continental scale
Hydro-ecological stream classification-the process of grouping streams by similar hydrologic responses and, by extension, similar aquatic habitat-has been widely accepted and is considered by some to be one of the first steps towards developing ecological flow targets. A new classification of 1543 streamgauges in the contiguous USA is presented by use of a novel and parsimonious approach to unders
Authors
Stacey A. Archfield, Jonathan Kennen, Daren Carlisle, David M. Wolock