WOBURN

iTONEHAM '

-

WINCHESTER

LEXINGTON

MALDEN

MEDFORD

ARLINGTON

CHELSEA

SOMERVILLE

BELMONT

CAMBRIDGE

WINTHROP

WILMINGTON

WAKEFIELD

BURLINGTON

Grade

Water Segment

Average
Compliance Rate

A+
A

Upper Mystic Lake
Island End River

98.56%
91.67%

B+

Chelsea River

83.28%

B+
B+
B-
B-

Mystic River (Salt)
Mystic River (Fresh)
Meetinghouse Brook
Belle Isle Inlet

81.43%
80.39%
72.50%
70.29%

C
C-

Aberjona River
Maiden River

64.37%
59.44%

D+

Mill Brook

54.71%

D+

Little River

52.56%

D

Alewife Brook

46.69%

D

Winns Brook

45.29%

F

Mill Creek

30.20%

REVERE

WATERTOWN

Mystic River Watershed Water Quality
reading	Grades and Compliance Rates - Calendar Year 2021

Average Compliance Rates for Swimming and Boating Standards

100-86

85-71

70-56

55-40

Monitoring Points

(fj) Mystic River Watershed Association
A Massachusetts Water Resources Authority

A



B



c



D



F

39-0

Mystic River Watershed
Town Boundary

2021 Mystic River
Watershed Report Card

(based on 2019-2021 bacterial data)

Data Sources: Mystic River Watershed Association, U.S. EPA, Massachusetts Water Resources Authority, MassGIS.
Basemap: Canvas/World Light Gray Base © ESRI and its data suppliers. EPA Region 1 GIS Center map #13390, 7/14/2022

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