Water Quality, Streamflow, and Habitat

OARS' water quality and streamflow monitoring focuses on a set of interrelated chemical and physical parameters that can be directly measured in the river and are relevant to habitat for fish and other aquatic creatures. These parameters are also among those used by the Mass DEP for setting water quality standards and regulating wastewater discharges (NPDES permits).

What and where do we monitor?
Water Quality Parameters: Dissolved oxygen, phosphorus (total and dissolved), nitrogen (nitrates and ammonia), suspended solids, conductivity, pH, and water temperature. Testing is done at 25 sites throughout the watershed.

Streamflow levels: OARS maintains staff gages to measure streamflows at nine tributary stream sites in the watershed; streamflow is recorded for these sites with every water quality sampling. Streamflow data is also recorded from USGS for their five continuous flow gages in the watershed:

• Assabet River in Maynard
• Concord River in Lowell
• Sudbury River in Saxonville/Framingham
• Nashoba Brook in Acton

Groundwater levels are recorded from the USGS monitoring well in Acton.

Availability of physical habitat: estimating the amount of the streambed that is covered with water gives an estimate of the amount of physical habitat available to fish. More about assessing physical habitat.

Read our latest water quality report.

Learn about volunteering with the sampling program.