Charles G Crawford, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 68
Estimation of suspended-sediment concentration from total suspended solids and turbidity data for Kentucky, 1978-1995
Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long‐term records were obtained from the National Water Information System of the U.S. Geological Surv
Authors
Tanja N. Williamson, Charles G. Crawford
Factors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States
We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models – 6 for total nitrogen and 6 for total phosphorus – all provide similar levels of prediction accuracy, but those
Authors
Stephen D. Preston, Richard B. Alexander, Gregory E. Schwarz, Charles G. Crawford
Regression models for explaining and predicting concentrations of organochlorine pesticides in fish from streams in the United States
Empirical regression models were developed for estimating concentrations of dieldrin, total chlordane, and total DDT in whole fish from U.S. streams. Models were based on pesticide concentrations measured in whole fish at 648 stream sites nationwide (1992-2001) as part of the U.S. Geological Survey's National Water Quality Assessment Program. Explanatory variables included fish lipid content, esti
Authors
Lisa H. Nowell, Charles G. Crawford, Robert J. Gilliom, Naomi Nakagaki, Wesley W. Stone, Gail Thelin, David M. Wolock
Watershed Regressions for Pesticides (WARP) for Predicting Annual Maximum and Annual Maximum Moving-Average Concentrations of Atrazine in Streams
Regression models were developed for predicting annual maximum and selected annual maximum moving-average concentrations of atrazine in streams using the Watershed Regressions for Pesticides (WARP) methodology developed by the National Water-Quality Assessment Program (NAWQA) of the U.S. Geological Survey (USGS). The current effort builds on the original WARP models, which were based on the annual
Authors
Wesley W. Stone, Robert J. Gilliom, Charles G. Crawford
Methods and Sources of Data Used to Develop Selected Water-Quality Indicators for Streams and Ground Water for the 2007 Edition of The State of the Nation's Ecosystems Report with Comparisons to the 2002 Edition
The U.S. Geological Survey (USGS) was one of numerous governmental, private, and academic entities that provided input to the report The State of the Nation?s Ecosystems published periodically by the Heinz Center. This report describes the sources of data and methods used by the USGS to develop selected water?quality indicators for the 2007 edition of the Heinz Center report and documents modifica
Authors
John T. Wilson, Nancy T. Baker, Michael J. Moran, Charles G. Crawford, Lisa H. Nowell, Patricia L. Toccalino, William G. Wilber
Simulation of daily pesticide concentrations from watershed characteristics and monthly climatic data
A time-series model was developed to simulate daily pesticide concentrations for streams in the coterminous United States. The model was based on readily available information on pesticide use, climatic variability, and watershed charac-teristics and was used to simulate concentrations for four herbicides [atrazine, ethyldipropylthiocarbamate (EPTC), metolachlor, and trifluralin] and three insecti
Authors
Aldo V. Vecchia, Charles G. Crawford
Regression model for explaining and predicting concentrations of Dieldrin in whole fish from United States streams
No abstract available.
Authors
Lisa H. Nowell, Charles G. Crawford, Naomi Nakagaki, Gail P. Thelin, David M. Wolock
Pesticides in the Nation's Streams and Ground Water, 1992–2001
This report is one of a series of publications, The Quality of Our Nation's Waters, that describe major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents evaluations of pesticides in streams and ground water based on findings for the first decadal cycle of NAWQA. 'Pesticides in the Nation's Streams and Ground Water, 1992-2001' greatly expa
Authors
Robert J. Gilliom, Jack E. Barbash, Charles G. Crawford, Pixie A. Hamilton, Jeffrey D. Martin, Naomi Nakagaki, Lisa H. Nowell, Jonathan C. Scott, Paul E. Stackelberg, Gail P. Thelin, David M. Wolock
Development of an approach for integrating components of the U.S. Geological Survey Biomonitoring of Environmental Status and Trends (BEST) and National Stream Quantity Accounting Network (NASQAN) programs for large U.S. rivers
A national-scale framework for monitoring environmental contaminants in fish and effects of contaminant exposure on fish in large U.S. rivers has been proposed by the Biomonitoring of Environmental Status and Trends (BEST) Program of the U.S. Geological Survey (USGS). The framework shares many features and objectives with the USGS National Stream Quantity Accounting Network (NASQAN) Program, which
Authors
Nancy J. Bauch, Christopher J. Schmitt, Charles G. Crawford
Development and Application of Watershed Regressions for Pesticides (WARP) for Estimating Atrazine Concentration Distributions in Streams
Regression models were developed for predicting atrazine concentration distributions in rivers and streams, using the Watershed Regressions for Pesticides (WARP) methodology. Separate regression equations were derived for each of nine percentiles of the annual distribution of atrazine concentrations and for the annual time-weighted mean atrazine concentration. In addition, seasonal models were dev
Authors
Steven J. Larson, Charles G. Crawford, Robert J. Gilliom
Sampling strategies for estimating acute and chronic exposures of pesticides in streams
The Food Quality Protection Act of 1996 requires that human exposure to pesticides through drinking water be considered when establishing pesticide tolerances in food. Several systematic and seasonally weighted systematic sampling strategies for estimating pesticide concentrations in surface water were evaluated through Monte Carlo simulation, using intensive datasets from four sites in northweste
Authors
Charles G. Crawford
Load estimator (LOADEST): a FORTRAN program for estimating constituent loads in streams and rivers
LOAD ESTimator (LOADEST) is a FORTRAN program for estimating constituent loads in streams and rivers. Given a time series of streamflow, additional data variables, and constituent concentration, LOADEST assists the user in developing a regression model for the estimation of constituent load (calibration). Explanatory variables within the regression model include various functions of streamflow, de
Authors
Robert L. Runkel, Charles G. Crawford, Timothy A. Cohn
Science and Products
Filter Total Items: 68
Estimation of suspended-sediment concentration from total suspended solids and turbidity data for Kentucky, 1978-1995
Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long‐term records were obtained from the National Water Information System of the U.S. Geological Surv
Authors
Tanja N. Williamson, Charles G. Crawford
Factors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States
We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models – 6 for total nitrogen and 6 for total phosphorus – all provide similar levels of prediction accuracy, but those
Authors
Stephen D. Preston, Richard B. Alexander, Gregory E. Schwarz, Charles G. Crawford
Regression models for explaining and predicting concentrations of organochlorine pesticides in fish from streams in the United States
Empirical regression models were developed for estimating concentrations of dieldrin, total chlordane, and total DDT in whole fish from U.S. streams. Models were based on pesticide concentrations measured in whole fish at 648 stream sites nationwide (1992-2001) as part of the U.S. Geological Survey's National Water Quality Assessment Program. Explanatory variables included fish lipid content, esti
Authors
Lisa H. Nowell, Charles G. Crawford, Robert J. Gilliom, Naomi Nakagaki, Wesley W. Stone, Gail Thelin, David M. Wolock
Watershed Regressions for Pesticides (WARP) for Predicting Annual Maximum and Annual Maximum Moving-Average Concentrations of Atrazine in Streams
Regression models were developed for predicting annual maximum and selected annual maximum moving-average concentrations of atrazine in streams using the Watershed Regressions for Pesticides (WARP) methodology developed by the National Water-Quality Assessment Program (NAWQA) of the U.S. Geological Survey (USGS). The current effort builds on the original WARP models, which were based on the annual
Authors
Wesley W. Stone, Robert J. Gilliom, Charles G. Crawford
Methods and Sources of Data Used to Develop Selected Water-Quality Indicators for Streams and Ground Water for the 2007 Edition of The State of the Nation's Ecosystems Report with Comparisons to the 2002 Edition
The U.S. Geological Survey (USGS) was one of numerous governmental, private, and academic entities that provided input to the report The State of the Nation?s Ecosystems published periodically by the Heinz Center. This report describes the sources of data and methods used by the USGS to develop selected water?quality indicators for the 2007 edition of the Heinz Center report and documents modifica
Authors
John T. Wilson, Nancy T. Baker, Michael J. Moran, Charles G. Crawford, Lisa H. Nowell, Patricia L. Toccalino, William G. Wilber
Simulation of daily pesticide concentrations from watershed characteristics and monthly climatic data
A time-series model was developed to simulate daily pesticide concentrations for streams in the coterminous United States. The model was based on readily available information on pesticide use, climatic variability, and watershed charac-teristics and was used to simulate concentrations for four herbicides [atrazine, ethyldipropylthiocarbamate (EPTC), metolachlor, and trifluralin] and three insecti
Authors
Aldo V. Vecchia, Charles G. Crawford
Regression model for explaining and predicting concentrations of Dieldrin in whole fish from United States streams
No abstract available.
Authors
Lisa H. Nowell, Charles G. Crawford, Naomi Nakagaki, Gail P. Thelin, David M. Wolock
Pesticides in the Nation's Streams and Ground Water, 1992–2001
This report is one of a series of publications, The Quality of Our Nation's Waters, that describe major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents evaluations of pesticides in streams and ground water based on findings for the first decadal cycle of NAWQA. 'Pesticides in the Nation's Streams and Ground Water, 1992-2001' greatly expa
Authors
Robert J. Gilliom, Jack E. Barbash, Charles G. Crawford, Pixie A. Hamilton, Jeffrey D. Martin, Naomi Nakagaki, Lisa H. Nowell, Jonathan C. Scott, Paul E. Stackelberg, Gail P. Thelin, David M. Wolock
Development of an approach for integrating components of the U.S. Geological Survey Biomonitoring of Environmental Status and Trends (BEST) and National Stream Quantity Accounting Network (NASQAN) programs for large U.S. rivers
A national-scale framework for monitoring environmental contaminants in fish and effects of contaminant exposure on fish in large U.S. rivers has been proposed by the Biomonitoring of Environmental Status and Trends (BEST) Program of the U.S. Geological Survey (USGS). The framework shares many features and objectives with the USGS National Stream Quantity Accounting Network (NASQAN) Program, which
Authors
Nancy J. Bauch, Christopher J. Schmitt, Charles G. Crawford
Development and Application of Watershed Regressions for Pesticides (WARP) for Estimating Atrazine Concentration Distributions in Streams
Regression models were developed for predicting atrazine concentration distributions in rivers and streams, using the Watershed Regressions for Pesticides (WARP) methodology. Separate regression equations were derived for each of nine percentiles of the annual distribution of atrazine concentrations and for the annual time-weighted mean atrazine concentration. In addition, seasonal models were dev
Authors
Steven J. Larson, Charles G. Crawford, Robert J. Gilliom
Sampling strategies for estimating acute and chronic exposures of pesticides in streams
The Food Quality Protection Act of 1996 requires that human exposure to pesticides through drinking water be considered when establishing pesticide tolerances in food. Several systematic and seasonally weighted systematic sampling strategies for estimating pesticide concentrations in surface water were evaluated through Monte Carlo simulation, using intensive datasets from four sites in northweste
Authors
Charles G. Crawford
Load estimator (LOADEST): a FORTRAN program for estimating constituent loads in streams and rivers
LOAD ESTimator (LOADEST) is a FORTRAN program for estimating constituent loads in streams and rivers. Given a time series of streamflow, additional data variables, and constituent concentration, LOADEST assists the user in developing a regression model for the estimation of constituent load (calibration). Explanatory variables within the regression model include various functions of streamflow, de
Authors
Robert L. Runkel, Charles G. Crawford, Timothy A. Cohn