EPA mystic river Report card

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The US Environmental Protection Agency (EPA) in collaboration with the Mystic River Watershed Association issues a water quality report card for the Mystic River Watershed each year. In 2014, the format of the grade changed from a watershed wide average to what you see below - a map offering waterbody by waterbody reporting. The grade is based on how frequently waterbodies meet bacteria standards for swimming and boating. You'll see that the Mystic River is a great place to go boating and the Mystic Lakes are a great place for a swim! The grade also shows that much work lies ahead in realizing the promise of the Clean Water Act in many of our waterbodies. See the 2018 grade below and read the EPA press release. Learn more about what impacts our water quality here.

How is Water Quality in the Mystic River watershed?

The Mystic River Watershed Association has been collecting water quality data and studying this question for over a decade and has your answer! 

Water quality in the Mystic River Watershed is comparable to many other urbanized watersheds-including the nearby Charles River-where dense development on land is contributing pollutants to the water. The data tell us that the water is clean enough to safely boat in the Mystic Lakes and River more than 90% of the time. But many areas of the watershed do not support swimming, boating or fishing as required by the Clean Water Act due to high levels of bacteria.

EPA Grade Assessment

The report card grades issued annually for the Mystic River by the EPA are based on the level of bacterial contamination found in samples collected by MyRWA volunteers over the past year at 15 monitoring sites throughout the entire watershed, as well as data collected at numerous locations by the Massachusetts Water Resources Authority (MWRA). The grades are calculated using a three-year rolling average, allowing for a more complete and accurate assessment of recent water quality that addresses weather variability from year to year.

The following graph and table show the 2018 water quality grades for each water body, using data from the last three years. The compliance rates represent the percentage of samples that met water quality standards for boating and swimming during that period:

2018 water quality graph.JPG
graph 1 2018 water quality.JPG
The baseline sampling location at Belle Isle Inlet changed in 2015 (BEI093 until 2014 - BEI001 starting in 2015). In 2015 and 2016 the grade (which takes into account three years of data) pooled data from the new site and the old.

The baseline sampling location at Belle Isle Inlet changed in 2015 (BEI093 until 2014 - BEI001 starting in 2015). In 2015 and 2016 the grade (which takes into account three years of data) pooled data from the new site and the old.