Watershed Regressions for Pesticides (WARP) models, previously developed for atrazine at the national scale, are improved for application to the United States (U.S.) Corn Belt region by developing region-specific models that include 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 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. The WARP-CB models accounted for 53 to 62% of the variability in the various concentration statistics among the model-development sites. Model predictions were within a factor of 5 of the observed concentration statistic for over 90% of the model-development sites. The WARP-CB residuals and uncertainty are lower than those of the National WARP model for the same sites. Although atrazine-use intensity is the most important explanatory variable in the National WARP models, it is not a significant variable in the WARP-CB models. The WARP-CB models provide improved predictions for Corn Belt streams draining watersheds with atrazine-use intensities of 17 kg/km2 of watershed area or greater.
Citation Information
Publication Year | 2012 |
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Title | Watershed regressions for pesticides (warp) models for predicting atrazine concentrations in Corn Belt streams |
DOI | 10.1111/j.1752-1688.2012.00661.x |
Authors | Wesley W. Stone, Robert J. Gilliom |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Journal of the American Water Resources Association |
Index ID | 70040508 |
Record Source | USGS Publications Warehouse |
USGS Organization | Indiana Water Science Center |