Overlapping Missions? USGS and NRCS

Here's a study of nitrates in rivers in the Mississippi basin, showing no consistent decline over the last 28 years (1980-2008).  What struck me is, while reported via a USDA agency (extension.org), the study itself was done by USGS.  Turns out there's something called The Mississippi River Gulf of Mexico Watershed Nutrient Action Task Force.  I guess NRCS is a part of it--there's an Ann Mills on the task force, though because the URL behind her name is screwed up I wasn't able to check on her.  The Task Force has EPA, Corps of Engineers, Interior (USGS), Commerce (NOAA), USDA (NRCS and extension), and the National Tribal Water Council.  Quite a group of agencies.