Nutrient Loads from the Upper Connecticut River Watershed

Science Center Objects

River-borne nutrients, especially nitrogen, contribute to water-quality degradation in Long Island Sound. The Connecticut River is the largest tributary to the Sound, and quantification of nutrient loads from the three upper States in the watershed, as well as the State of Connecticut, is essential for prioritizing efforts to improve the Sound’s water quality. 

In order to distinguish the combined nutrient load from the upper watershed States (New Hampshire, Vermont, and Massachusetts) from the State of Connecticut load, a new USGS monitoring station has been established for continuous streamflow measurement and weekly nutrient sampling at the Connecticut River at Northfield, MA, near the MA/NH/VT border. Sampling is also continuing at the MA/CT State line, at the existing Connecticut River at Thompsonville, CT station. The specific project objectives are to:

  • Install, operate, and maintain a side-looking acoustic Doppler velocity meter (ADVM) at the Northfield, MA site, for measurement of streamflow.
  • Collect weekly cross-sectional, composite water-quality samples for total and dissolved nitrogen and phosphorus constituents and standard field parameters. Document weather conditions for the 48 hours prior to sample collection.
  • Increase sampling frequency at the Thompsonville, CT station to weekly, to match that of the Northfield station. Collect Thompsonville samples 24 to 30 hours after the Northfield samples, to account for the average travel time of a parcel of water between the two sites.
  • Develop a workplan for continued monitoring for a total of five years of data collection. Prepare an interpretative report describing nutrient loads at the Northfield site after three years of data collection.