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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Streamflow - Water Year 2017
The maps and graphs in this summary describe national streamflow conditions for water year 2017 (October 1, 2016, to September 30, 2017) in the context of streamflow ranks relative to the 88-year period of 1930–2017, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey (USGS) National Streamflow Network (U.S. Geological Survey, 2018a). The period of
Authors
Xiaodong Jian, David M. Wolock, Steven J. Brady, Harry F. Lins
Warming is driving decreases in snow fractions while runoff efficiency remains mostly unchanged in snow-covered areas of the western United States
Winter snowfall and accumulation is an important component of the surface water supply in the western United States. In these areas, increasing winter temperatures T associated with global warming can influence the amount of winter precipitation P that falls as snow S. In this study we examine long-term trends in the fraction of winter P that falls as S (Sfrac) for 175 hydrologic units (HUs) in sn
Authors
Gregory J. McCabe, David M. Wolock, Melissa Valentin
A new indicator framework for quantifying the intensity of the terrestrialwater cycle
A quantitative framework for characterizing the intensity of the water cycle over land is presented, and illustrated using a spatially distributed water-balance model of the conterminous United States (CONUS). We approach water cycle intensity (WCI) from a landscape perspective; WCI is defined as the sum of precipitation (P) and actual evapotranspiration (AET) over a spatially explicit landscape u
Authors
Thomas G. Huntington, Peter Weiskel, David M. Wolock, Gregory J. McCabe
Variability of hydrological droughts in the conterminous United States, 1951 through 2014
Spatial and temporal variability in the frequency, duration, and severity of hydrological droughts across the conterminous United States (CONUS) was examined using monthly mean streamflow measured at 872 sites from 1951 through 2014. Hydrological drought is identified as starting when streamflow falls below the 20th percentile streamflow value for 3 consecutive months and ending when streamflow re
Authors
Samuel H. Austin, David M. Wolock, David L. Nelms
A conceptual framework for effectively anticipating water-quality changes resulting from changes in agricultural activities
Agricultural activities can affect water quality and the health of aquatic ecosystems; many water-quality issues originate with the movement of water, agricultural chemicals, and eroded soil from agricultural areas to streams and groundwater. Most agricultural activities are designed to sustain or increase crop production, while some are designed to protect soil and water resources. Numerous soil-
Authors
Paul D. Capel, David M. Wolock, Richard H. Coupe, Jason L. Roth
Predictability and selection of hydrologic metrics in riverine ecohydrology
The natural flow regime is critical to the health of riverine ecosystems. Many hydrologic metrics (HMs) have been developed to describe natural flow regimes, quantify flow alteration, and provide the hydrologic foundation for the development of environmental flow standards. Many applications require the use of models to predict expected natural values of HMs from basin characteristics at sites wit
Authors
Ken Eng, Theodore E. Grantham, Daren Carlisle, David M. Wolock
Evidence that recent warming is reducing upper Colorado River flows
The upper Colorado River basin (UCRB) is one of the primary sources of water for the western United States, and increasing temperatures likely will elevate the risk of reduced water supply in the basin. Although variability in water-year precipitation explains more of the variability in water-year UCRB streamflow than water-year UCRB temperature, since the late 1980s, increases in temperature in t
Authors
Gregory J. McCabe, David M. Wolock, Gregory T. Pederson, Connie A. Woodhouse, Stephanie A. McAfee
Estimating discharge and nonpoint source nitrate loading to streams from three end‐member pathways using high‐frequency water quality data
The myriad hydrologic and biogeochemical processes taking place in watersheds occurring across space and time are integrated and reflected in the quantity and quality of water in streams and rivers. Collection of high‐frequency water quality data with sensors in surface waters provides new opportunities to disentangle these processes and quantify sources and transport of water and solutes in the c
Authors
Matthew P. Miller, Anthony J. Tesoriero, Krista Hood, Silvia Terziotti, David M. Wolock
Biological relevance of streamflow metrics: Regional and national perspectives
Protecting the health of streams and rivers requires identifying ecologically significant attributes of the natural flow regime. Streamflow regimes are routinely quantified using a plethora of hydrologic metrics (HMs), most of which have unknown relevance to biological communities. At regional and national scales, we evaluated which of 509 commonly used HMs were associated with biological indicato
Authors
Daren Carlisle, Theodore E. Grantham, Ken Eng, David M. Wolock
Streamflow alteration and habitat ramifications for a threatened fish species in the Central United States
In the Central United States, the Arkansas darter (Etheostoma cragini) is listed as a threatened fish species by the State of Kansas. Survival of the darter is threatened by loss of habitat caused by changing streamflow conditions, in particular flow depletion. Future management of darter populations and habitats requires an understanding of streamflow conditions and how those conditions may have
Authors
Kyle E. Juracek, Ken Eng, Daren Carlisle, David M. Wolock
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
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 127
Streamflow - Water Year 2017
The maps and graphs in this summary describe national streamflow conditions for water year 2017 (October 1, 2016, to September 30, 2017) in the context of streamflow ranks relative to the 88-year period of 1930–2017, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey (USGS) National Streamflow Network (U.S. Geological Survey, 2018a). The period of
Authors
Xiaodong Jian, David M. Wolock, Steven J. Brady, Harry F. Lins
Warming is driving decreases in snow fractions while runoff efficiency remains mostly unchanged in snow-covered areas of the western United States
Winter snowfall and accumulation is an important component of the surface water supply in the western United States. In these areas, increasing winter temperatures T associated with global warming can influence the amount of winter precipitation P that falls as snow S. In this study we examine long-term trends in the fraction of winter P that falls as S (Sfrac) for 175 hydrologic units (HUs) in sn
Authors
Gregory J. McCabe, David M. Wolock, Melissa Valentin
A new indicator framework for quantifying the intensity of the terrestrialwater cycle
A quantitative framework for characterizing the intensity of the water cycle over land is presented, and illustrated using a spatially distributed water-balance model of the conterminous United States (CONUS). We approach water cycle intensity (WCI) from a landscape perspective; WCI is defined as the sum of precipitation (P) and actual evapotranspiration (AET) over a spatially explicit landscape u
Authors
Thomas G. Huntington, Peter Weiskel, David M. Wolock, Gregory J. McCabe
Variability of hydrological droughts in the conterminous United States, 1951 through 2014
Spatial and temporal variability in the frequency, duration, and severity of hydrological droughts across the conterminous United States (CONUS) was examined using monthly mean streamflow measured at 872 sites from 1951 through 2014. Hydrological drought is identified as starting when streamflow falls below the 20th percentile streamflow value for 3 consecutive months and ending when streamflow re
Authors
Samuel H. Austin, David M. Wolock, David L. Nelms
A conceptual framework for effectively anticipating water-quality changes resulting from changes in agricultural activities
Agricultural activities can affect water quality and the health of aquatic ecosystems; many water-quality issues originate with the movement of water, agricultural chemicals, and eroded soil from agricultural areas to streams and groundwater. Most agricultural activities are designed to sustain or increase crop production, while some are designed to protect soil and water resources. Numerous soil-
Authors
Paul D. Capel, David M. Wolock, Richard H. Coupe, Jason L. Roth
Predictability and selection of hydrologic metrics in riverine ecohydrology
The natural flow regime is critical to the health of riverine ecosystems. Many hydrologic metrics (HMs) have been developed to describe natural flow regimes, quantify flow alteration, and provide the hydrologic foundation for the development of environmental flow standards. Many applications require the use of models to predict expected natural values of HMs from basin characteristics at sites wit
Authors
Ken Eng, Theodore E. Grantham, Daren Carlisle, David M. Wolock
Evidence that recent warming is reducing upper Colorado River flows
The upper Colorado River basin (UCRB) is one of the primary sources of water for the western United States, and increasing temperatures likely will elevate the risk of reduced water supply in the basin. Although variability in water-year precipitation explains more of the variability in water-year UCRB streamflow than water-year UCRB temperature, since the late 1980s, increases in temperature in t
Authors
Gregory J. McCabe, David M. Wolock, Gregory T. Pederson, Connie A. Woodhouse, Stephanie A. McAfee
Estimating discharge and nonpoint source nitrate loading to streams from three end‐member pathways using high‐frequency water quality data
The myriad hydrologic and biogeochemical processes taking place in watersheds occurring across space and time are integrated and reflected in the quantity and quality of water in streams and rivers. Collection of high‐frequency water quality data with sensors in surface waters provides new opportunities to disentangle these processes and quantify sources and transport of water and solutes in the c
Authors
Matthew P. Miller, Anthony J. Tesoriero, Krista Hood, Silvia Terziotti, David M. Wolock
Biological relevance of streamflow metrics: Regional and national perspectives
Protecting the health of streams and rivers requires identifying ecologically significant attributes of the natural flow regime. Streamflow regimes are routinely quantified using a plethora of hydrologic metrics (HMs), most of which have unknown relevance to biological communities. At regional and national scales, we evaluated which of 509 commonly used HMs were associated with biological indicato
Authors
Daren Carlisle, Theodore E. Grantham, Ken Eng, David M. Wolock
Streamflow alteration and habitat ramifications for a threatened fish species in the Central United States
In the Central United States, the Arkansas darter (Etheostoma cragini) is listed as a threatened fish species by the State of Kansas. Survival of the darter is threatened by loss of habitat caused by changing streamflow conditions, in particular flow depletion. Future management of darter populations and habitats requires an understanding of streamflow conditions and how those conditions may have
Authors
Kyle E. Juracek, Ken Eng, Daren Carlisle, David M. Wolock
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