By Tom Bannister

On Tuesday, May 31, EPA Regional Administrator, Curt Spalding in coordination with the Mystic River Watershed Association, U.S. Representative Michael Capuano, Somerville Mayor Joseph Curtatone and Massachusetts Water Resources Authority announced the localized grades for the Mystic River Watershed. The grades are specified for each segment of the watershed, totaling 14 separate stretches of river and tributaries.

The grades are based on bacterial contamination found in analyzed samples that were collected by MyRWA volunteers over the past year at fifteen monitoring sites throughout the entire watershed, as well as data collected at numerous locations by the Massachusetts Water Resources Authority (MWRA). From 2006 to 2013, an overall grade was used to track water quality progress in the Mystic River Watershed. Beginning in 2014, the amount of data collected each year supports an improved and more sophisticated grading system, where a grade can be assigned, using similar criteria as in the past, to each major segment or tributary in the Mystic River watershed.

For the second year in a row, analysis of the data shows that water quality in the main stem of the Mystic River, including the Upper and Lower Mystic Lakes, is quite good on a regular basis. On the other hand, water quality in many of the urban tributary streams in the Mystic River watershed is poor. Water quality in the main stem of the river from the Mystic Lakes, through Medford Square, and on to Boston Harbor, meets water quality standards nearly all of the time, especially in dry weather.

However, water quality in many of the tributary streams feeding the Mystic often do not meet water quality standards. Water quality is frequently poor due to bacterial contamination in tributary streams such as Winn’s Brook, Little River, Mill Brook, the Malden River, the Island End River, and Mill Creek, even in dry weather. Investigations to date indicate the main causes of high bacteria counts in these water bodies to be illicit sewer discharges to storm drain systems and uncontrolled urban stormwater runoff that contains pet and animal waste.

A three-year rolling average was again used to calculate the grade for each segment. A grade for each year is calculated and the current year’s grade is averaged with the prior two years to produce the “rolling” three-year average. Such a system allows for a more complete and accurate assessment of recent water quality and is designed to better address climate variability from year to year, while allowing for real data trends to be more easily discerned.

“We have a lot of ongoing work to improve water quality in the Mystic and its tributaries, and this report card serves as motivation to continue that work. EPA and our partners are committed to improving water quality for residents of the Mystic Watershed, and while we have seen improvements, we still have a lot of work to do,” said Curt Spalding, regional administrator of EPA’s New England office. “This year we have seen water quality improvements in 10 of the 14 segments of the River, and four of those have had grade improvements. The most significant grade improvement this year is Belle Isle Inlet, which improved from a C to a B in 2015, meeting state water quality standards 77.8% percent of days in 2015 compared to 63.9% in 2014.”

“The grade demonstrates the recreational value of the Mystic River and Lakes. These are great places for canoeing and kayaking and we can safely enjoy swimming in the Upper Mystic Lake,” said EkOngKar Singh Khalsa, Executive Director of the Mystic River Watershed Association. “The grade also underlines where there is room for improvement.”

“The Mystic River Watershed is a valuable natural resource accessible to many Greater Boston communities and its water quality is important, not only for recreational use but for the wildlife found in and around its waters. I am encouraged that we are moving in the right direction along key areas of the Watershed. I thank the Mystic River Watershed Association and the EPA for their commitment to improving water quality standards in the areas where it is still very much needed and protecting this local treasure,” stated U.S. Congressman Michael Capuano.