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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Nitrate Loads and Concentrations in Surface-Water Base Flow and Shallow Groundwater for Selected Basins in the United States, Water Years 1990-2006 Nitrate Loads and Concentrations in Surface-Water Base Flow and Shallow Groundwater for Selected Basins in the United States, Water Years 1990-2006
Hydrograph separation was used to determine the base-flow component of streamflow for 148 sites sampled as part of the National Water-Quality Assessment program. Sites in the Southwest and the Northwest tend to have base-flow index values greater than 0.5. Sites in the Midwest and the eastern portion of the Southern Plains generally have values less than 0.5. Base-flow index values for...
Authors
Norman E. Spahr, Neil M. Dubrovsky, JoAnn M. Gronberg, O. Lehn Franke, David M. Wolock
Development and Application of Regression Models for Estimating Nutrient Concentrations in Streams of the Conterminous United States, 1992-2001 Development and Application of Regression Models for Estimating Nutrient Concentrations in Streams of the Conterminous United States, 1992-2001
Data collected for the U.S. Geological Survey National Water-Quality Assessment program from 1992-2001 were used to investigate the relations between nutrient concentrations and nutrient sources, hydrology, and basin characteristics. Regression models were developed to estimate annual flow-weighted concentrations of total nitrogen and total phosphorus using explanatory variables derived...
Authors
Norman E. Spahr, David K. Mueller, David M. Wolock, Kerie J. Hitt, JoAnn M. Gronberg
Design of Cycle 3 of the National Water-Quality Assessment Program, 2013-2022: Part 1: Framework of Water-Quality Issues and Potential Approaches Design of Cycle 3 of the National Water-Quality Assessment Program, 2013-2022: Part 1: Framework of Water-Quality Issues and Potential Approaches
In 1991, the U.S. Congress established the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program to develop long-term, nationally consistent information on the quality of the Nation's streams and groundwater. Congress recognized the critical need for this information to support scientifically sound management, regulatory, and policy decisions concerning the...
Authors
Gary L. Rowe, Kenneth Belitz, Hedeff I. Essaid, Robert J. Gilliom, Pixie A. Hamilton, Anne B. Hoos, Dennis D. Lynch, Mark D. Munn, David W. Wolock
Streamflow of 2009--Water year summary Streamflow of 2009--Water year summary
The maps and graph in this summary describe streamflow conditions for water-year 2009 (October 1, 2008 to September 30, 2009) in the context of the 80-year period 1930-2009, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's National Streamflow Information Program. The period 1930-2009 was used because prior to 1930, the number of...
Authors
Jian Xiaodong, David M. Wolock, Harry F. Lins, Steve Brady
Long-term variability in Northern Hemisphere snow cover and associations with warmer winters Long-term variability in Northern Hemisphere snow cover and associations with warmer winters
A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of...
Authors
Gregory J. McCabe, David M. Wolock
Long-term variability in Northern Hemisphere snow cover and associations with warmer winters Long-term variability in Northern Hemisphere snow cover and associations with warmer winters
A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of...
Authors
G.J. McCabe, D.M. Wolock
Science and Products
Filter Total Items: 13
No Result Found
Filter Total Items: 134
Nitrate Loads and Concentrations in Surface-Water Base Flow and Shallow Groundwater for Selected Basins in the United States, Water Years 1990-2006 Nitrate Loads and Concentrations in Surface-Water Base Flow and Shallow Groundwater for Selected Basins in the United States, Water Years 1990-2006
Hydrograph separation was used to determine the base-flow component of streamflow for 148 sites sampled as part of the National Water-Quality Assessment program. Sites in the Southwest and the Northwest tend to have base-flow index values greater than 0.5. Sites in the Midwest and the eastern portion of the Southern Plains generally have values less than 0.5. Base-flow index values for...
Authors
Norman E. Spahr, Neil M. Dubrovsky, JoAnn M. Gronberg, O. Lehn Franke, David M. Wolock
Development and Application of Regression Models for Estimating Nutrient Concentrations in Streams of the Conterminous United States, 1992-2001 Development and Application of Regression Models for Estimating Nutrient Concentrations in Streams of the Conterminous United States, 1992-2001
Data collected for the U.S. Geological Survey National Water-Quality Assessment program from 1992-2001 were used to investigate the relations between nutrient concentrations and nutrient sources, hydrology, and basin characteristics. Regression models were developed to estimate annual flow-weighted concentrations of total nitrogen and total phosphorus using explanatory variables derived...
Authors
Norman E. Spahr, David K. Mueller, David M. Wolock, Kerie J. Hitt, JoAnn M. Gronberg
Design of Cycle 3 of the National Water-Quality Assessment Program, 2013-2022: Part 1: Framework of Water-Quality Issues and Potential Approaches Design of Cycle 3 of the National Water-Quality Assessment Program, 2013-2022: Part 1: Framework of Water-Quality Issues and Potential Approaches
In 1991, the U.S. Congress established the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program to develop long-term, nationally consistent information on the quality of the Nation's streams and groundwater. Congress recognized the critical need for this information to support scientifically sound management, regulatory, and policy decisions concerning the...
Authors
Gary L. Rowe, Kenneth Belitz, Hedeff I. Essaid, Robert J. Gilliom, Pixie A. Hamilton, Anne B. Hoos, Dennis D. Lynch, Mark D. Munn, David W. Wolock
Streamflow of 2009--Water year summary Streamflow of 2009--Water year summary
The maps and graph in this summary describe streamflow conditions for water-year 2009 (October 1, 2008 to September 30, 2009) in the context of the 80-year period 1930-2009, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's National Streamflow Information Program. The period 1930-2009 was used because prior to 1930, the number of...
Authors
Jian Xiaodong, David M. Wolock, Harry F. Lins, Steve Brady
Long-term variability in Northern Hemisphere snow cover and associations with warmer winters Long-term variability in Northern Hemisphere snow cover and associations with warmer winters
A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of...
Authors
Gregory J. McCabe, David M. Wolock
Long-term variability in Northern Hemisphere snow cover and associations with warmer winters Long-term variability in Northern Hemisphere snow cover and associations with warmer winters
A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of...
Authors
G.J. McCabe, D.M. Wolock