READING

Mystic River Watershed Water Quality
Grades and Compliance Rates - Calendar Year 2020

WILMINGTON

BURLINGTON

WATERTOWN

BOSTON

A+

Island End River

96.9%

A

Upper Mystic Lake

93.2%

A

Chelsea River

90.9%

B+

Mystic River (Fresh Water)

81.9%

B

Mystic River (Salt Water)

79.8%

B

Belle Isle Inlet

78.1%

C+

Meetinghouse Brook

70.0%

c-

Maiden River

59.6%

c

Aberjona River

58.8%

D+

Little River

51.0%

D

Mill Brook

48.6%

D

Alewife Brook

46.5%

D

Winns Brook

45.7%

F

Mill Creek

32.9%

0.5

N

s

1

2

3 Miles

Average Compliance Rates for Swimming and Boating Standards

A



B



C



D



F

100-86

85-71

70-56

55-40

Monitoring Points

^ ) Mystic River Watershed Association

Massachusetts Water Resources Authority

39-0

Mystic River Watershed
Town Boundary

2020 Mystic River
Watershed Report Card

(based on 2018-2020 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, 7/14/2021

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