Blog - Charles River Watershed Association

Making Way for the Head of the Charles!

Posted by Alexandra Flowers

10/21/16 5:37 PM

Head of the Charles

Boston skyline from the BU Bridge during the 2014 Head of the Charles Regatta. Source: Bill Damon | CC BY 2.0

Early on Tuesday and Thursday mornings, CRWA interns and volunteers head out on the Charles River along with many others. As rowers head out to prepare for the world renowned race, The Head of the Charles Regatta, we are preparing to test the quality of the water. As we begin our long journey down the Charles to the Longfellow bridge in a small motor boat (trying to dodge all the rowers along the way), we finally make it to the furthest point of our trek about two hours later. We shut the boat off to prepare sample bottles. We will sample water from the Charles River near four different bridges.

Alexandra Flowers

Alexandra Flowers, Watershed Science Intern at CRWA, drives the boat to the sampling sites.

After labeling the sterilized sampling bottles, we drive under the middle entrance of each of the four bridges. While grabbing the sample it is important that the boat is turned to the side when the sample is taken to ensure that the water collected is coming from downstream. At this point in time we also record temperature, depth, and time as this could have a possible effect on the samples. Once we have gathered our samples we store them in a cooler to keep them fresh. The samples are then driven to a lab in Quincy where they are tested for E .coli. The presence of E. coli bacteria (short for escherichia coli) in the water suggests contamination by sewage, which could mean disease-causing bacteria or viruses are present. View the biweekly water quality sampling data online. 


Testing for E. coli bacteria requires at least 24 hours before results are determined. To overcome this delay, CRWA has developed a water forecasting model to predict water quality based on parameters collected in real-time including recent rainfall, wind speed, and river flow. We let people know the forecasted water quality on our website, in email and twitter alerts and with the help of our partner boathouses. Ten boathouses in the Charles River lower basin hang flags outside their boathouse indicating whether or not the current water quality is safe for boaters. Boathouses hang three different colored flags, each with a different meaning. A blue flag indicates suitable boating conditions. A yellow flag indicates that the data is inconclusive to preclude possible health risks and that caution should be taken. We also fly yellow flags when a cyanobacteria (blue-green algae) bloom is present. A red flag indicates that there are potential health risks.


The Charles river is safe to boat on most of the time. However it is less likely to meet water quality standards after a rainfall. When it rains, polluted runoff, which may contain garbage, car exhaust, nutrients and other pollution, collects and dumps into the river. During a heavy rainstorm, stormwater may exceed the capacity of the combined sewer system in parts of Boston and Cambridge, causing the stormwater and sewage to overflow into the Charles River with only minimal treatment. Cyanobacteria is another threat to boaters' safety. Now in its 7th week, a cyanobacteria bloom currently impacts the Charles River downstream of the Massachusetts Avenue bridge.Our public notification website allows us to help boaters make smart decisions based on the facts. 


Stay up to date with live water quality forecasts throughout the Head of the Charles Regatta weekend! Whether you are rowing or watching we hope you have a fabulous experience.


Topics: Charles River, Stormwater, Stormwater Management, Pollution, Charles River Pollution, Stormwater Runoff, Head of the Charles Regatta

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About Charles River Watershed Association:

One of the country's oldest watershed organizations, Charles River Watershed Association (CRWA) was formed in 1965 in response to public concern about the declining condition of the Charles. Since its earliest days of advocacy, CRWA has figured prominently in major clean-up and watershed protection efforts, working with government officials and citizen groups from 35 Massachusetts watershed towns from Hopkinton to Boston. Initiatives over the last fifty years have dramatically improved the quality of water in the watershed and fundamentally changed approaches to water resource management.