I have had a few inquiries for other science agencies; may be of interest
to others:

Real-Time Tracking of Nitrate Concentrations in the Mississippi River Basin:

example station, Mississippi River at Baton Rouge, LA:

USGS news release: Real-time Monitoring Pays Off for Tracking Nitrate Pulse
in Mississippi River Basin to the Gulf of Mexico:

Just a reminder, the NAWQA program ( data
retrievable by constituent:
constituent finder:

Also, SPARROW Surface Water-Quality Modeling:

USGS NWIS: USGS Water Data for the Nation:

Most library users find it easiest to use the NWIS Mapper interface to
search for data:

for mobile users (beta):

Enjoy the day,

Emily Wild
Librarian (Physical Scientist)
U.S. Geological Survey
Denver Library
Box 25046, MS 914
Denver Federal Center
Denver, CO 80225-0046
ph: (303) 236-1003
[log in to unmask]

USGS Libraries:
Professional Page: