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Mystic River Watershed Report Cards

Mystic River Report Card Map 2019EPA produced a watershed map for 2019 that identifies areas in the watershed where water quality is generally good and generally needs improvement.EPA has been assigning a report card grade for the Mystic River Watershed since calendar year 2006. For the last five years, grades have been assigned to 14 individual stretches of the river and its tributaries. Prior to 2014, a single grade was assigned to the watershed as a whole.

Grading Criteria 2014-Present

Since calendar year 2014, EPA, in coordination with the Mystic River Watershed Association (MyRWA), has utilized an enhanced, more locally-specific analysis of water quality in the Mystic River Watershed to better illuminate environmental conditions for the public. Instead of one grade for the entire watershed, EPA and MyRWA now issue grades for each segment of the watershed, totaling 14 separate stretches of river and its tributaries. The same grading system applies (see below), but now an average between the overall percentages that water quality met the state criteria for swimming and boating (for the Aberjona in 2016, it was 61.8%) as well as qualitative criteria that are similar to those developed for the Charles River Initiative (see below) are calculated for each segment to produce the grades shown here.

Chart of 2019 Compliance Rates and Grades for the Mystic RiverView a larger version of this image.
Figure 1 - Developed and provided by MyRWA.

Mystic River Water Quality Grades & Compliance Rates for Freshwater Sites
  2019 2018 2017 2016 2015 2014
Sites Grade Total Grade Total Grade Total Grade Total Grade Total Grade Total
Aberjona River C- 55.7% D+ 52.6% C- 59.4% C 61.8% C+ 66% C+ 65%
Alewife Brook D 45.6% D 50.0% D+ 53.8% D+ 54.2% D 50% D 46%
Little River D+ 50.7% D+ 52.6% D+ 54.2% D 49.4% D- 44% D- 40%
Malden River C 63.9% C 60.1% C 63.7% C+ 65.1% C 63% C- 59%
Meetinghouse Brook B- 72.6% B- 71.9% B 78.4% C+ 66.5% C- 58% D 47%
Mill Brook D+ 50.5% D 49.4% C- 55.1% D+ 53.1% D 49% D- 46%
Mystic River (fresh) A- 85.5% A- 86.9% A- 87.6% A- 85.8% A- 85% B+ 85%
Upper Mystic Lake A 92.9% A 93.4% A+ 98.6% A+ 98.9% A+ 96% A+ 96%
Winns Brook F 36.3% D- 40.1% F 38.4% D- 42% F 33% F 33%
Mystic River Water Quality Grades & Compliance Rates for Saltwater Sites
  2019 2018 2017 2016 2015 2014
Sites Grade Total Grade Total Grade Total Grade Total Grade Total Grade Total
Belle Isle Inlet B+ 83.8% A- 86.0% A- 89.3% A- 85.7% B 78% C 64%
Chelsea River A 90.4% A 95.0% A 94.6% A 91.2% A- 90% A- 87%
Island End River B 76.3% C+ 66.7% D- 42.5% F 36.3% F 25% F 33%
Mill Creek D- 41.3% F 36.1% F 31.3% F 33.5% F 34% F 32%
Mystic River (salt) B+ 83.7% A- 86.0% A- 88.3% A- 87.6% A- 89% A 90%

For more information on how the grades are assigned please read the Frequently Asked Questions and review the data on MyRWA's Website Exit.

2018 Report Card
2017 Report Card
2016 Report Card
2015 Report Card
2014 Report Card

Grading Criteria Prior to 2014

When assessing water quality to assign a grade to the Mystic River Watershed prior to 2014, EPA used an average between the overall percentages that water quality met the state criteria for swimming and boating (for 2013, it was 66%) as well as qualitative criteria that are similar to those developed for the Charles River Initiative, as follows:

A - met swimming and boating standards nearly all of the time
B - met swimming and boating standards most of the time
C - met swimming standards some of the time, and boating standards most of the time
D - met swimming and boating standards some of the time
F - fail swimming and boating standards most of the time

Mystic River Report Cards: 2003 - 2013
Year Grade Overall* Dry* Wet*
  Boating Swimming Boating Swimming Boating Swimming
2013 D 83% 49% 88% 51% 67% 42%
2012 D 75% 47% 84% 58% 45% 14%
2011 D 87% 46% 93% 54% 69% 25%
2010 D- 70% 28% 72% 26% 63% 33%
2009 C- 93% 57% 93% 51% 90% 75%
2008 C- 90% 59% 93% 64% 81% 43%
2007 D 68% 46% 63% 45% 83% 50%
2006 D 80% 52% 93% 59% 41% 30%
2005**   85% 56% 90% 64% 69% 31%
2004**   79% 52% 85% 59% 61% 59%
2003**   81% 55% 81% 53% 81% 62%
*Figures represent the percentage of time that state bacterial standards are met.
**The Mystic River Watershed did not receive formal grades for the years 2003 - 2005.

Mystic River in the News

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