This mapper displays SPARROW nutrient load and yield data and the importance of various nutrient sources for the MRB3 (U.S. part of the Great Lakes basin and the Ohio, Upper Mississippi, and Red River basins), given nutrient inputs similar to 2002. Rankings can be shown by major watershed, state, HUC8, tributary, and catchment. Nutrient data can be explored using maps and interactive graphs and tables. Modeling data can be exported as an Excel spreadsheet.