PSU students help collect streamflow data

On Saturday, September 24, NHDES staff instructed Plymouth State University (PSU) Environmental Science & Policy students in Dr. Lisa Doner’s Advanced Field Techniques class. Joe Schmidl of the Instream Flow (ISF) Program described streamflow measurement theory and techniques and then took the students to the Ammonoosuc River to make a streamflow measurement.

The ISF Program has installed nine near real-time streamflow stations around the state this summer to support the study of instream flows in the state’s designated rivers. These stations rely on manual streamflow measurements to relate water depth measurements collected by the automatic units to streamflow. NHDES took this opportunity to engage PSU students to collect additional water depth and streamflow data at one of these stations.

The students first received instruction in a PSU lab to learn the principles behind streamflow measurement, the techniques employed, the concept of a rating curve that relates river level to streamflow, and observed current streamflow data from the upper Ammonoosuc River in Crawford’s Purchase that is reported from NHDES’ streamflow station there. The Ammonoosuc River at this station was at its highest level since its installation in June, which emphasized the need for additional streamflow measurements. The class then went to Crawford’s Purchase, where NHDES’ station 28G-AMM is located off Base Station Road. The class formed three teams, setting up taglines and measuring streamflow.

The students got a real “feel” for what it is like to work as an environmental scientist. It was a crisp, clear September day at the foot of Mount Washington, with the water temperature about 45°F and a stiff streamflow of 1 to 2 feet per second that required careful footing to avoid an uncomfortable dip. By the end of the hour-long measurement, everyone had cold feet, regardless of whether their waders leaked. Each team compiled their 20 separate streamflow measurements into an accurate estimate of streamflow; all three results were close, met NHDES’ quality control criteria, and have been used to extend the rating curve for this station’s flow measurements upward from 58 to 88 cubic feet per second. Thanks to all for your help protecting New Hampshire’s rivers!