BOSTON — The U.S. Environmental Protection Agency (EPA) and the Mystic River Watershed Association (MyRWA) have a new method to grade water quality in the Mystic River Watershed, according to a press release.

Each segment of the watershed will now receive its own grade instead of one grade for entire region, noted the release. The watershed is comprised of 14 stretches of river and tributaries.

MyRWA volunteers and the Massachusetts Water Resources Authority collected samples to determine the grades, reported the release. They are based on bacterial contamination found in the samples.

The main sections of the river were found to have good water quality on a regular basis, while many tributaries do not meet quality standards, shared the release. Grades ranged from A+ for the Upper Mystic Lake to an F for Mill Creek. The main causes of bacterial contamination are illicit sewer discharges to storm drain systems and stormwater runoff.

As part of the changes, a three-year rolling average will be used to determine each grade, stated the release. The system should allow for more accurate and complete information.

“Grading the watershed by segments provides the public with a more accurate assessment of local water quality conditions and greater transparency for all stakeholders,” said Curt Spalding, regional administrator of EPA’s New England office, in the release. “It also helps EPA, MyRWA and other agencies to focus our efforts on the segments with lower water quality. We also hope local communities will step up efforts to reduce illicit discharges.”

EPA and the Mass. Dept. of Environmental Protection’s recent enforcement efforts removed more than 31,000 gallons of sewage per day from storm drains in the watershed, noted the release. Repairs and the removal of illicit connections will contribute to greater water quality.

Click here to read the entire release.