Boston Harbor Rivers 2021 Report Cards Show Significant Improvement

BOSTON — On the 50th anniversary of the Clean Water Act, U.S. Senator Ed Markey, and U.S. Environmental Protection Agency revealed the 2021 Water Quality Report Card Grades Friday for the three rivers that flow into Boston Harbor: the Neponset, the Charles, and the Mystic.

The 2021 Report Card Grades, which range from A to F, show extensive improvement compared to decades before, yet present new challenges in ensuring the rivers are clean, healthy, and safe for all.

The Clean Water Act began with a 1972 landmark legislation calling for all waterways in America to be "fishable and swimmable" by 1983, with hopes to eliminate all discharges of pollutants into waters by 1985.

While those goals are yet to be achieved, the Clean Water Act has provided a much-needed face-lift to the Neponset, Charles, and Mystic Rivers. Those three used to be industrial dumping grounds, flowing raw sewage and toxic pollutants into the Boston Harbor making it inhospitable to plant and animal life.

In 2021, Massachusetts saw fifty-two inches of rainfall, twenty-four days above 90 degrees, and several flash flooding events, all of which influenced water quality grades in the Mystic, Charles, and Neponset Rivers.

The grades, which are based on the percentage of time E. Coli bacterial levels are safe for recreation, precipitation data, and weighted with a three-year average, are influenced by increased precipitation. Additionally, grades for the Charles River account for the presence of cyanobacteria blooms and combined-sewer overflow discharges - two additional threats to public health, that are each respectively exacerbated by extreme heat and increased rainfall.

Grades for the Neponset River

In the Neponset River watershed, most streams and river segments earned grades of "A" or "B", and all monitored ponds earned "A's". Only Unquity Brook, Germany Brook, and Meadow Brook received grades of "D" or "F". In addition, the mainstem of the Neponset, where most recreation occurs, received grades in the "B" range, indicating that the river met boating standards and often swimming standards as well.

In March, almost four miles of the Neponset River that goes through Boston and Milton became designated as a Superfund Site by the EPA. The Superfund Program was created in 1980 to allow the EPA to clean up hazardous waste sites and require those responsible to perform cleanups or pay back the government for those efforts.

Early studies from the EPA found that the 3.7-mile stretch of river is contaminated with elevated levels of polychlorinated biphenyls, or PCBs. These chemicals, which can't break down in the environment, are considered to be "probable human carcinogens" by the EPA and are known to impact the health and safety of animals in the area.

The biggest challenge in the Neponset is polluted stormwater runoff from streets, parking lots, and yards. When it rains, pollutants on our roadways and parking lots– oil, gas, bacteria, pharmaceuticals, and more– are washed directly into our waterways. In wet weather, water quality grades drop 22 percent on average, nearly two full letter grades, impairing water quality
and rendering many areas of the river unsafe for recreation.

Grades for the Charles River

In the Charles River, grades ranged from "A's" in the middle reaches - Sherborn to Waltham, to a "C-" in the Muddy River, a tributary in Brookline and Boston. The Upper Watershed - Hopkinton to Medfield, received a "B+", mainly a result of low water levels and encroaching development in the area causing more polluted stormwater runoff. The Lower Basin of the Charles River, the popular boating reach between Watertown and Boston, received a "B-" due to persistent combined-sewer overflows.

In Summer 2021, due to a record thirty-five inches of rain, fifty-three known combined-sewage overflow events, and over 126 million gallons of sewage and stormwater were discharged into the Charles: about the volume of 36 Olympic-sized swimming pools. Combined-sewage overflow events are extremely dangerous, exposing river users and watershed residents to pollutant-laden water, carrying bacteria, excess nutrients, pharmaceuticals, and even harmful PFAS compounds. The increased frequency and volume of CSO events alone dropped the Lower Basin's grade from a "B" to a "B-."

Grades for the Mystic River

The Mystic River itself and the Mystic Lakes receive grades from "B+" to "A+", indicating that they meet boating standards almost all the time in dry weather; and some important tributaries, including Winn's Brook in Belmont, Alewife Brook in Cambridge and Arlington, and Mill Creek in Chelsea continue to show clear evidence of frequent contamination by wastewater, earning the lowest grades.

The Alewife Brook tributary stands out as a place where infrastructure improvements should be
prioritized to protect Environmental Justice communities. Stormwater from four urban
municipalities, Cambridge, Somerville, Arlington, and Belmont, and frequent combined-sewer overflows in Cambridge and Somerville, all flow into Alewife Brook and pose significant health risks to residents.

"Today's reporting of water quality in the major urban rivers of Boston and surrounding communities underscores the hard work that has contributed to healthier waters, while also spotlighting locations and types of pollution that still need to be addressed. All of our citizens
deserve to enjoy a clean and healthy environment, especially in historically underserved communities," said EPA New England Regional Administrator David W. Cash.