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...
Streamflow—Water year 2020
The maps and graphs in this summary describe national streamflow conditions for water year 2020 (October 1, 2019, to September 30, 2020) in the context of streamflow ranks relative to the 91-year period of water years 1930–2020. Annual runoff in the Nation’s rivers and streams during water year 2020 (11.10 inches) was higher than the long-term (...
Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Henderson, Ronald J.; Brady, Steven J.
Multi-year hydroclimatic droughts and pluvials across the conterminous United States
Time series of water‐year runoff for 2,109 hydrologic units (HUs) across the conterminous United States (CONUS) for the 1900 through 2014 period were used to identify drought and pluvial (i.e., wet) periods. Characteristics of the drought and pluvial events including frequency, duration, and severity were examined and compared. Additionally, a...
McCabe, Gregory J.; Wolock, David M. Spatial and temporal patterns of low streamflow and precipitation changes in the Chesapeake Bay Watershed
Spatial and temporal patterns in low streamflows were investigated for 183 streamgages located in the Chesapeake Bay Watershed for the period 1939–2013. Metrics that represent different aspects of the frequency and magnitude of low streamflows were examined for trends: (1) the annual time series of seven‐day average minimum streamflow, (2) the...
Fleming, Brandon J.; Archfield, Stacey A.; Hirsch, Robert M.; Kiang, Julie E.; Wolock, David M.
Streamflow—Water year 2019
The maps and graphs in this summary describe national streamflow conditions for water year 2019 (October 1, 2018, to September 30, 2019) in the context of streamflow ranks relative to the 90-year period of water years 1930–2019. Annual runoff in the Nation’s rivers and streams during water year 2019 (13.62 inches) was much higher than the long-...
Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steven J. Hydro-climatic drought in the Delaware River Basin
The Delaware River Basin (DRB) supplies water to approximately 15 million people and is essential to agriculture and industry. In this study, a monthly water balance model is used to compute monthly water balance components (i.e., potential evapotranspiration, actual evapotranspiration, and runoff [R]) for the DRB for the 1901 through 2015 period...
McCabe, Gregory J.; Wolock, David M. Prioritizing river basins for intensive monitoring and assessment by the US Geological Survey
The US Geological Survey (USGS) is currently (2020) integrating its water science programs to better address the nation’s greatest water resource challenges now and into the future. This integration will rely, in part, on data from 10 or more intensively monitored river basins from across the USA. A team of USGS scientists was convened to develop...
Van Metre, Peter C.; Qi, Sharon L.; Deacon, Jeffrey R.; Dieter, Cheryl A.; Driscoll, Jessica M.; Fienen, Michael N.; Kenney, Terry A.; Lambert, Patrick M.; Lesmes, David; Mason, Christopher Allen; Mueller-Solger, Anke; Musgrove, MaryLynn; Painter, Jaime A.; Rosenberry, Donald O.; Sprague, Lori A.; Tesoriero, Anthony J.; Windham-Myers, Lisamarie; Wolock, David M. The water-year water balance of the Colorado River Basin
Model‐estimated monthly water balance components (i.e., potential evapotranspiration, actual evapotranspiration, and runoff (R)) for 146 United States (U.S.) Geological Survey 8‐digit hydrologic units located in the Colorado River Basin (CRB) are used to examine the temporal and spatial variability of the CRB water balance for water years 1901...
McCabe, Gregory J.; Wolock, David M.
Severity and extent of alterations to natural streamflow regimes based on hydrologic metrics in the conterminous United States, 1980–2014
Alteration of the natural streamflow regime by land and water management, such as land-cover change and dams, is associated with aquatic ecosystem degradation. The severity and geographic extent of streamflow alteration at regional and national scales, however, remain largely unquantified. The primary goal of this study is to characterize the...
Eng, Ken; Carlisle, Daren; Grantham, Theodore E.; Wolock, David M.; Eng, Rosaly L.
Flow modification in the Nation’s streams and rivers
This report summarizes a national assessment of flowing waters conducted by the U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Project and addresses several pressing questions about the modification of natural flows in streams and rivers. The assessment is based on the integration, modeling, and synthesis of...
Carlisle, Daren; Wolock, David M.; Konrad, Christopher P.; McCabe, Gregory J.; Eng, Ken; Theodore E. Grantham; Mahler, Barbara
Streamflow—Water year 2018
The maps and graphs in this summary describe national streamflow conditions for water year 2018 (October 1, 2017, to September 30, 2018) in the context of streamflow ranks relative to the 89-year period of water years 1930–2018. The illustrations are based on observed data from the U.S. Geological Survey National Streamflow Network. Annual runoff...
Jian, Xiaodong; Wolock, David M.; Brady, Steven J.; Lins, Harry F.
Regional-scale associations between indicators of biological integrity and indicators of streamflow modification
Although streamflow is widely recognized as a controlling factor in stream health, empirical relations between indicators of anthropogenic modification of streamflow and ecological indicators have been elusive. The objective of this report is to build upon specific findings reported in recent publications by providing a library of empirical models...
Carlisle, Daren; Grantham, Theodore E.; Eng, Ken; Wolock, David M. 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...
Huntington, Thomas G.; Weiskel, Peter; Wolock, David M.; McCabe, Gregory J.
Software Release - RSPARROW: An R system for SPARROW modeling
RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model, with new features that improve the utility of the model for conducting studies of contaminants in surface waters and informing water resource management decisions.