| Abstract: | Watershed Regressions for Pesticides (WARP) models, previously developed for atrazine at the national scale, can be improved for application to the U.S. Corn Belt region by developing region-specific models that include important watershed characteristics that are influential in predicting atrazine concentration statistics within the Corn Belt. WARP models for the Corn Belt (WARP-CB) were developed for predicting annual maximum moving-average (14-, 21-, 30-, 60-, and 90-day durations) and annual 95th-percentile atrazine concentrations in streams of the Corn Belt region. All streams used in development of WARP-CB models drain watersheds with atrazine use intensity greater than 17 kilograms per square kilometer (kg/km2). The WARP-CB models accounted for 53 to 62 percent of the variability in the various concentration statistics among the model-development sites.
The 95-percent prediction intervals are well within a factor of 10 above and below the predicted concentration statistic. WARP-CB model predictions were within a factor of 5 of the observed concentration statistic for over 90 percent of the model-development sites. The WARP-CB residuals and uncertainty are lower than those of the National WARP model for the same sites. The WARP-CB models provide improved predictions of the probability of exceeding a specified criterion or benchmark for Corn Belt streams draining watersheds with high atrazine use intensities; however, National WARP models should be used for Corn Belt streams where atrazine use intensities are less than 17 kg/km2 of watershed area. |
| Genre: | USGS Numbered Series |
| ProdID: | 70004698 |
| Citation Author: | Stone, Wesley W.; Gilliom, Robert J. |
| Citation Contributing Office: | Indiana Water Science Center |
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| Citation Phsyical Description: | vii, 15 p.; Appendices; Appendix 1; Appendix 2 |
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| Citation Public Comments: | National Water-Quality Assessment Program |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 2011-1141 |
| Citation Search Results Text: | Watershed regressions for pesticides (WARP) for predicting atrazine concentration in Corn Belt streams; 2011; OFR; 2011-1141; Stone, Wesley W.; Gilliom, Robert J. |
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| Citation Year: | 2011 |
| Type: | citation/reference |
| Text: | Watershed regressions for pesticides (WARP) for predicting atrazine concentration in Corn Belt streams; 2011; OFR; 2011-1141; Stone, Wesley W.; Gilliom, Robert J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/ofr_2011_1141.gif |
| URL (INDEX PAGE): | http://pubs.usgs.gov/of/2011/1141/ |
| Date Other: | Tue, 21 Jun 2011 16:50 -0500 |
| Publisher: | U.S. Geological Survey |
