ICYMI: New Grades for Mystic River Watershed Gives More Local Analysis

The Mystic River Watershed Association is implementing a new grading system that will give the public more locally-specific analyses on water quality.

The United States Environmental Protection Agency (EPA) said grades will be given for each segment of the watershed, rather than one grade for the entire watershed. The entire watershed spans 14 separate stretches of rivers and tributaries.

There are 44 lakes and ponds within the Watershed, with Spot Pond being the largest standing body of water at 307 acres in size. There are 22 communities within the Mystic River Watershed including Winchester.

The grades given are based on bacterial contamination found in analyzed samples collected from 15 sites throughout the watershed by Mystic River Watershed Association (MyRWA) volunteers over the past year, the EPA said. Additionally, data collected at numerous locations by the Massachusetts Water Resources Authority will also affect the grades.

The 2014 data collected indicated the water quality in the main portion of the Mystic River, including both Upper and Lower Mystic Lakes, is good on a regular basis. Tributary streams in more urban areas, however, have shown poor water quality, the EPA said.

Another change to the grading system is that a three-year rolling average will be implemented to calculate the grade for each segment. This rolling average provides for a more accurate assessment of recent water quality and enables climate variability to be addressed from year to year, the agency said.

“Grading the watershed by segments provides the public with a more accurate assessment of local water quality conditions and greater transparency for all stakeholders,” Curt Spalding, regional administrator of EPA’s New England office, said in a release from the agency. “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.”

Additional ongoing efforts have been made to try and increase the water quality of the Mystic River Watershed, including the removal of tens of thousands of gallons of sewage per day from storm drains in the watershed.

Below are the water quality grades and compliance rates for the 2014 calendar year for the Mystic River Watershed:

A+ Upper Mystic Lake 96%
A Mystic River (Salt Water) 90%
A- Chelsea Creek 87%

B+ Mystic River (Fresh Water) 85%
C+ Aberjona River 65%
C Belle Isle Inlet 64%
C- Malden River 59%

D Meetinghouse Brook 47%
D Alewife Brook 46%
D- Mill Brook 43%
D- Little River 40%

F Winn’s Brook 33%
F Island End River 33%
F Mill Creek 32%