Nancy T. Baker

Comparative Study of Transport Processes of Nitrogen, Phosphorus, and Herbicides to Streams in Five Agricultural Basins, USA

Agricultural chemical transport to surface water and the linkage to other hydrological compartments, principally ground water, was investigated at five watersheds in semiarid to humid climatic settings. Chemical transport was affected by storm water runoff, soil drainage, irrigation, and how streams were linked to shallow ground water systems. Irrigation practices and timing of chemical use greatly affected nutrient and pesticide transport in the semiarid basins. Irrigation with imported water tended to increase ground water and chemical transport, whereas the use of locally pumped irrigation water may eliminate connections between streams and ground water, resulting in lower annual loads. Drainage pathways in humid environments are important because the loads may be transported in tile drains, or through varying combinations of ground water discharge, and overland flow. In most cases, overland flow contributed the greatest loads, but a significant portion of the annual load of nitrate and some pesticide degradates can be transported under base-flow conditions. The highest basin yields for nitrate were measured in a semiarid irrigated system that used imported water and in a stream dominated by tile drainage in a humid environment. Pesticide loads, as a percent of actual use (LAPU), showed the effects of climate and geohydrologic conditions. The LAPU values in the semiarid study basin in Washington were generally low because most of the load was transported in ground water discharge to the stream. When herbicides are applied during the rainy season in a semiarid setting, such as simazine in the California basin, LAPU values are similar to those in the Midwest basins.

Estimated annual agricultural pesticide use for counties of the conterminous United States, 1992--2009

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Datasets for the Report Entitled: "A Method for Addressing Differences in Concentrations of Fipronil and Three Degradates Obtained by Two Different Laboratory Methods"

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 arranged in 9 tables that include water-quality site information, laboratory recovery data, laboratory analyses results and measured water-sample concentrations analyzed by the two laboratory methods, and estimated concentrations from the older method removing the effects of method differences.

Agricultural Pesticide Use Estimates for Selected Watersheds of the Surface Water Trends Project, 1992-2014, National Water Quality Program

The U.S. Geological Survey (USGS) National Water Quality Program (NWQP) provides an understanding of water-quality conditions; whether conditions are getting better or worse over time; and how natural features and human activities affect those conditions. The Surface Water Trends (SWT) project of NWQP evaluates the directions, periods, and statistical significance of trends in water quality in streams and rivers. This data release was generated for SWT and provides annual agricultural pesticide use (1992-2014) for selected watersheds where long-term water quality is measured and where subsequent trend analysis will be conducted. County-level pesticide use estimates for 33 compounds were allocated to agricultural land for 70 SWT watersheds.

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 modifications in the data sources and interpretations between the 2002 and 2007 editions of the Heinz Center report. Stream and ground-water quality data collected nationally as part of the USGS National Water-Quality Assessment Program were used to develop the ecosystem indicators for the Heinz Center report, including Core National indicators for the Movement of Nitrogen and Chemical Contamination and for selected ecosystems classified as Farmlands, Forest, Grasslands and Shrublands, Freshwater, and Urban and Suburban. In addition, the USGS provided water-quality and streamflow data collected as part of the National Stream Water Quality Accounting Network and the Federal–State Cooperative Program. The documentation provided herein serves not only as a reference for current and future editions of The State of the Nation’s Ecosystems but also provides critical information for future assessments of changes in contaminant occurrence in streams and ground water of the United States.

Fish community and habitat data at selected sites in the White River Basin, Indiana, 1993-95

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INVENTORY OF PUBLIC WATER SUPPLIES IN ARKANSAS

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