David M Wolock, Ph.D.
Science and Products
A digital crust to advance continental‐scale modeling of subsurface fluid flow in climate, crustal process, and Earth system models
Fluid circulation in the Earth’s crust plays an essential role in surface, near surface, and crustal dynamics. Near the surface, soil water and groundwater interact with each other and with rivers, lakes and wetlands, affecting weathering, soil formation, ecosystem evolution and biogeochemical cycles. Further down (1km), fluid flow affects diagenesis, hydrocarbon maturation and migration, ore...
A database of natural monthly streamflow estimates from 1950 to 2015 for the conterminous United States
Quantifying and understanding the natural streamflow regime, defined as expected streamflow that would occur in the absence of anthropogenic modification to the hydrologic system, is critically important for the development of management strategies aimed at protecting aquatic ecosystems. Water balance models have been applied frequently to...
Miller, Matthew P.; Carlisle, Daren M.; Wolock, David M.; Wieczorek, Michael
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...
Jian, Xiaodong; Wolock, David M.; Brady, Steven J.; Lins, Harry F.
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...
Austin, Samuel H.; Wolock, David M.; Nelms, David L.
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...
Capel, Paul D.; Wolock, David M.; Coupe, Richard H.; Roth, Jason L. 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...
Eng, Ken; Grantham, Theodore E.; Carlisle, Daren M.; Wolock, David M. 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...
Miller, Matthew P.; Tesoriero, Anthony J.; Hood, Krista; Terziotti, Silvia; Wolock, David M. 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...
Carlisle, Daren M.; Grantham, Theodore E.; Eng, Ken; Wolock, David M. 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...
Juracek, Kyle E.; Eng, Ken; Carlisle, Daren M.; Wolock, David M.
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...
Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steven J. 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...
McCabe, Gregory J.; Wolock, David M.; Austin, Samuel H.
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....
Carlisle, Daren M.; Wolock, David M.; Howard, Jeannette K.; Grantham, Theodore E.; Fesenmyer, Kurt; Wieczorek, Michael
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...
Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steve