You can still swim in the Charles

View of the Charles River from the Boston University Bridge.

Via ecoRI News (ecori.org)

BOSTON

The Environmental Protection Agency (EPA) recently gave a grade of B for water quality last year in the Charles River. This is a slight reduction from the B+ grade awarded for water quality in the river in 2015.

EPA and state and local partners have worked to improve water quality in the Charles River for more than two decades. This is the 22nd year EPA has issued a Charles River Report Card. The 2016 grade of B reflects EPA analysis of bacterial contamination in water samples taken monthly from the lower Charles River by the Charles River Watershed Association (CRWA) at 10 sampling stations between Watertown and Boston.

In 2016, the Charles River met Massachusetts's bacterial water-quality standards for boating 86 percent of the time and for swimming 55 percent of the time. The grade is determined according to the following criteria:

A: Almost always met standards for boating and swimming
B: Met standards for almost all boating and some swimming
C: Met standards for some boating and some swimming
D: Met standards for some boating but no swimming
F: Didn’t meet standards for boating or swimming

The grade is also based on a comparison to previous years’ grades and whether the water quality has improved. The slightly lower grade for 2016 is likely related to the fact that seven out of 10 sample events occurred during or immediately after a rain event, despite the overall drought conditions that occurred throughout the region during most of 2016, according to EPA.

The lower Charles River has improved dramatically from the launch of EPA’s Charles River Initiative in 1995, when the river received a D for meeting boating standards only 39 percent of the time and swimming standards just 19 percent of the time. Improvements are due to a significant reduction in the amount of sewage discharged into the river during the past 20 years from combined sewer overflows and illicit discharges through storm drains. Illicit discharges often consist of cracked and leaking sewer pipes or improper sewer connections to the storm-drain system.

For the third year, EPA has launched a water-quality monitoring buoy in front of the Museum of Science in the Charles River Lower Basin. This buoy measures water quality in near real time, and the data can be viewed on EPA’s Charles River Web site and viewed as part of an exhibit on the Charles River in the Museum of Science.

The 2016 calendar year saw further expansion on the public’s enjoyment of the long-term trend of improved water quality in the Charles River, illustrated by some 140 swimmers competing in the Charles River Swim, a mile swim held in June, and the release of a study for a permanent swimming area near the entrance to the Charles at North Point Park.

Aside from illicit discharges, stormwater containing phosphorus, and the algae it produces, are some of the major pollution problems remaining. A major load of phosphorus comes from fertilizer and runoff from impervious surfaces such as roads and rooftops.