Charles River Report Card

Determining the Health of Our Watershed in 2020

July 19, 2021

Background

In 2019, with the assistance of CRWA, U.S. EPA developed a new grading system that reports on the entire 80 miles of the Charles River and two of its tributaries, the Stop River and the Muddy River.

In addition to E. coli data, the report card grades now take into account cyanobacteria (toxic blue-green algae) blooms and combined sewer overflows (CSOs), two public health concerns that are hazardous for anyone who comes into contact with the water.

Read the full press release here .

The 2020 report card grades would not be possible without the significant contributions of over 80 volunteer community scientists -Lisa Kumpf, CRWA Aquatic Scientist

Data Collection

CRWA collects bacteria samples through our Volunteer Monthly Monitoring (VMM) and Flagging programs , and monitors cyanobacteria bloom in the river each summer. Water samples are collected once each month at 39 locations in the watershed. These data, collected monthly by more than eighty loyal volunteers, help CRWA study the health of the river and recommend solutions. CRWA is able to assist municipalities, environmental agencies, and other organizations work to minimize stormwater impacts and reduce sewage contamination in the river.

Become a VMM

Sampling Sites

All 39 sampling sites on the Charles River

2020 Results

Grades are issued for four sections of the Charles River mainstem: the Upper Watershed (Hopkinton to Medfield), the Upper Middle Watershed (Sherborn to Dedham), the Lower Middle Watershed (Newton to Waltham), and the Lower Basin (Watertown to Boston). Two tributaries of the Charles are also graded: the Stop River in Medfield, and the Muddy River in Boston.

Grades are calculated based on the percentage of days during both dry and wet weather when the bacteria levels at each of the 39 sampling sites meet the Massachusetts water quality standards for swimming and boating.

To account for sampling variability, the past three years of E. coli data are used to calculate the percentage of time each river segment complied with standards. If a sample site was affected by a CSO and/or cyanobacteria bloom advisory, the percentage of days over the three-year period affected by an advisory is subtracted from the E. coli percentage to determine the final grade.

Upper Watershed

Hopkinton, Milford, Hopedale, Bellingham, Franklin, Medway, Norfolk, Millis, Medfield

Upper Middle Watershed

Medfield, Sherborn, Dover, Natick, Needham, Wellesley, Westwood, Dedham, Boston, Newton

Lower Middle Watershed

Newton, Wellesley, Weston, Waltham, Watertown

Lower Basin

Watertown, Newton, Brookline, Boston, Cambridge

Muddy River

Tributary of the Charles River in Boston

Upper Watershed

Hopkinton, Milford, Hopedale, Bellingham, Franklin, Medway, Norfolk, Millis, Medfield

Water quality in the Upper Watershed is moderately degraded (B+) compared to the Middle reaches of the watershed.

As the river flows from its source in Hopkinton, it runs along the I-495 corridor, which is experiencing rapid development from the road and building constructions. Additionally, water levels in the headwaters of the Charles can get low. Less water results in more concentrated pollution, which is reflected in the sample results and grade.

To improve the health of the Upper Watershed, municipalities need to focus on identifying conservation opportunities and implementing local regulations on developers.

CRWA works closely with the Upper Watershed municipalities on these issues by advocating for restoration and the incorporation of green stormwater infrastructure into urban design.

Currently, CRWA is assessing the removal of Eagle Dam with the Town of Wrentham and the construction of a green stormwater infrastructure within Milford Town Park to restore habitat and build climate resilience.

Upper Middle Watershed

Medfield, Sherborn, Dover, Natick, Needham, Wellesley, Westwood, Dedham, Boston, Newton

Water quality in the Lower Middle Watershed is very good (A) compared to the Upper and Lower reaches of the Charles.

As the river flows from Sherborn to Dedham, it is surrounded by significant areas of preserved forests and wetlands that serve as a habitat for wildlife and create recreation opportunities.

The plants and soils in these natural spaces act as filters, cleaning the water of pollutants. The resulting grade of the Upper Middle Charles emphasizes the importance of wetlands, biodiversity, and protected land in nourishing a healthy river.

Currently, CRWA is working with the Town of Natick to develop a 'green streets' design on Pond Street.

Lower Middle Watershed

Newton, Wellesley, Weston, Waltham, Watertown

Water quality in the Lower Middle Watershed is good (A-) compared to the Upper and Lower reaches of Charles.

As the river flows from Needham to Waltham, it passes through suburban neighborhoods and open spaces. While there is some habitat for wildlife and ample recreation opportunities, there are significant areas of impervious ground cover from increasing development and ageing stormwater infrastructure. Without filtration of the plants and soils in open spaces, untreated stormwater runoff during wet weather events contributes to elevated E. coli levels in parts of the Lower Middle watershed.

CRWA works closely with the Lower Middle Watershed municipalities on these issues by advocating for restrictions on the development and incorporation of green stormwater infrastructure into urban design. Currently, CRWA is working with the community of Newton to naturalize Cheesecake Brook , which would improve water quality, restore stream habitat, and reduce stormwater flooding.

Lower Basin

Watertown, Newton, Brookline, Boston, Cambridge

Water quality in the Lower Basin of the Charles is degraded (B-).

From Watertown to Boston Harbor, the river passes through high-density urban areas. In these more developed areas, rain washes pollutants from roads and buildings into storm drains that lead directly to the Charles without getting filtered.

The Lower Basin historically suffers from prolonged cyanobacteria blooms and frequent sewage overflows into the river during heavy rainfall. The calculated grade reflects current threats to recreation.

To improve the health of the Lower Basin, upgrades to ageing infrastructure need to be made and green stormwater infrastructure needs to be incorporated in the urban design of the area.

CRWA works closely with the Lower Basin Watershed municipalities on these issues by advocating for green stormwater infrastructure initiatives and connecting the communities within our watershed. Currently, CRWA, in partnership with the Friends of Herter Park and Charles River Conservancy, launched the Herter Park Green Infrastructure Laboratory to engage residents of Allston-Brighton in field science, stewardship and education.

Muddy River

Tributary of the Charles River in Boston

Water quality in the Muddy River is extremely degraded (D-).

The Muddy River tributary originates in Jamaica Pond and flows all the way into the Charles River through highly developed urban areas. This 3.5-mile long route along the Emerald Necklace, passes through Olmsted Park's ponds, the Riverway and the Back Bay Fens, under the MassPike to the Charlesgate, and through 200-foot pipes under Storrow Drive before reaching the Charles River.

The effect of a highly urbanized watershed is especially apparent in the Muddy River. Untreated stormwater enters directly into the Charles River carrying road toxins, pet waste, and excess phosphorus that reduces water quality in the Lower Basin.

CRWA works with other organizations to oversee the Muddy River Restoration Project. The project aims to restore the river by increasing flooding capacity, daylighting sections of the river, and restoring the riverbank conditions.

Progress in the Charles

**(Left)** Cars dumped into the Charles River (1963. Image credit: H Shippen Goodhue). **(Right)** CRWA aquatic scientist, Lisa, sampling in the Charles (2019)

From a D to a B-, the Charles River has come a long way since the 1960s when trash, sewage, and cars were dumped into the river. Portions of the river which were once uninhabitable for many aquatic species now teem with life. The Charles River is transformed into a beloved place for walking, boating, fishing, and cycling. Through sound science, advocacy and passion, the Charles has become a major example of how public voice can alter the course of history and restore a river.

The wide variety in Charles River grades from an A in the middle watershed to the D- in the Muddy River reflect the predominant land use around each area. Areas with more development and impervious surface are more polluted. We have work to do to restore all areas of the Charles to be ecologically healthy -Emily Norton, CRWA Executive Director

Get Involved

CRWA continues to work with many local municipalities on developing long-term, cutting edge solutions to address climate change in the watershed.

Check out how to get involved here and stay up to date on CRWA projects by subscribing to our newsletter !

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FAQs

What E. coli level considered safe for swimming and boating?

The Commonwealth of Massachusetts has standards of 235 and 1260 E. coli per 100 mL of water as levels that should not be exceeded for safe swimming and boating conditions, respectively.

Where do CSO data come from?

The CSO data compiled was from reports produced by MWRA and the City of Cambridge , documenting overflow events.

What is the difference between the Charles River, Neponset River and Mystic River report card grades?

All systems use the same methods to calculate the E. coli portion of the grades, but the Charles River grades include additional data from CSOs and cyanobacteria blooms. Another difference is due to the geometry of the river systems, as the Charles has a long main stem with smaller tributaries, the Mystic River and Neponset Rivers both have larger tributaries that coalesce to a shorter main stem. In addition, the Charles River system is entirely freshwater, bounded at its end by the New Charles River Dam, whereas tidal flow enters the Mystic River below the Amelia Earhart Dam, and the Neponset gives way to the Neponset estuary. Massachusetts’ standards for bacterial pollution are different for fresh and saltwater, so there is a slight difference in the grade calculation in the saltwater reaches of the Mystic and Neponset. For these reasons, it is important to note that the grades should not be directly compared against one another. However, these grades do provide a basis to track annual progress and water quality within each watershed.