Charles G. Crawford
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View article: Comparison of surrogate models to estimate pesticide concentrations at six U.S. Geological Survey National Water Quality Network sites during water years 2013–18
Comparison of surrogate models to estimate pesticide concentrations at six U.S. Geological Survey National Water Quality Network sites during water years 2013–18 Open
First posted January 31, 2023 For additional information, contact: Director, Ohio-Kentucky-Indiana Water Science CenterU.S. Geological Survey5957 Lakeside Blvd.Indianapolis, IN 46278-1996Contact Pubs Warehouse During water years 2013–18, t…
View article: Nitrogen and Phosphorus Concentration Thresholds toward Establishing Water Quality Criteria for Pennsylvania, USA
Nitrogen and Phosphorus Concentration Thresholds toward Establishing Water Quality Criteria for Pennsylvania, USA Open
Nutrient enrichment is currently a leading cause of impairment to streams in Pennsylvania. Evaluating the water quality condition and eutrophic status of streams and rivers is a challenge without established thresholds for nutrient concent…
View article: Differential effects of land use on nutrient concentrations in streams of Pennsylvania
Differential effects of land use on nutrient concentrations in streams of Pennsylvania Open
Nutrient pollution of surface waters is a widespread problem, calling for regional assessments of water quality conditions. In this study, we quantified long-term median nutrient concentrations of total nitrogen (TN) and total phosphorus (…
View article: An evaluation of methods for computing annual water-quality loads
An evaluation of methods for computing annual water-quality loads Open
First posted September 25, 2019 For additional information, contact: Chief, National Water-Quality Assessment Program U.S. Geological Survey 413 National Center 12201 Sunrise Valley Drive Reston, VA 20192 The U.S. Geological Survey publish…
View article: A method for addressing differences in concentrations of fipronil and three degradates obtained by two different laboratory methods
A method for addressing differences in concentrations of fipronil and three degradates obtained by two different laboratory methods Open
First posted July 21, 2017 For additional information, contact: National Water-Quality Assessment Project U.S. Geological Survey 5957 Lakeside Boulevard Indianapolis, IN 46278 In October 2012, the U.S. Geological Survey (USGS) began measur…
View article: Methods for computing water-quality loads at sites in the U.S. Geological Survey National Water Quality Network
Methods for computing water-quality loads at sites in the U.S. Geological Survey National Water Quality Network Open
First posted October 24, 2017 Revised August 26, 2021 For additional information, contact: Director, Kansas Water Science Center U.S. Geological Survey1217 Biltmore DriveLawrence, KS 66049 The U.S. Geological Survey currently (2020) publis…
View article: Datasets for the Report Entitled: "A Method for Addressing Differences in Concentrations of Fipronil and Three Degradates Obtained by Two Different Laboratory Methods"
Datasets for the Report Entitled: "A Method for Addressing Differences in Concentrations of Fipronil and Three Degradates Obtained by Two Different Laboratory Methods" Open
This report provides data input and computation results for a method developed by Crawford and Martin (2017) to address differences in concentrations of fipronil and three degradates obtained by two different laboratory methods. Data are a…
View article: An evaluation of methods for estimating decadal stream loads
An evaluation of methods for estimating decadal stream loads Open
Effective management of water resources requires accurate information on the mass, or load of water-quality constituents transported from upstream watersheds to downstream receiving waters. Despite this need, no single method has been show…