Charles River Watershed Association

Symposium on Water Resources and the World Wide Web
Seattle, Washington, December 5-9, 1999

FIGURE 15: EMPACT/FLAGGING TABLE OF CONTENTS PAGE Links may not work 1999 Charles River Basin Water Quality Information
Scroll down the page for a summary of today's water quality conditions on the Charles River Basin. = suitable boating conditions = potential health risks associated with elevated bacteria levels Click on site name for current data.
Newton Yacht Club
Community Rowing Inc.
Henderson (Northeastern) Boathouse
Charles River Canoe & Kayak (Herter Park)
Weld (Harvard) Boathouse
Riverside Boat Club
Boston University Sailing Pavilion
MIT Sailing Pavilion
Community Boating
Click one of the following years to download an Excel file of archived data: 1999 1998
Click here for map of monitoring locations.

From May through October, Charles River Watershed Association tests water quality in the Charles River Basin five times a week at four sites. Test results indicate levels of bacteria (fecal coliform) for each site. Bacteria levels are measured by counting colony-forming units of fecal coliform per 100 milliliters (about a teacup of water) after test samples have incubated for 24 hours. A blue flag is posted when the bacteria level meets the boating standard (less than 1,000/100ml) set by the Massachusetts Department of Environmental Protection. If the bacteria level count exceeds 1,000/100ml on a sampling date, a red flag is posted to indicate a health risk. Red flags signal that water quality near testing sites does not meet the boating standard. The presence of fecal bacteria in water suggests contamination with sewage or feces, which in turn could mean that disease-causing bacteria or viruses are present.

Most red flag days occur after heavy rainfall when stormdrains and sewer system overflows flush pollutants into the river. CRWA research shows that the Basin does not meet state boating standards over 25% of the time after a heavy rain.

When it rains heavily on a given day, elevated bacteria levels and the posted flag color at a site may not match the previous day's bacteria levels as indicated on this website. For instance, we may post a red flag if rainfall accumulation reaches a certain point even before we receive test results from the previous day. This is because CRWA strives to provide the public with the most up-to-date information about boating conditions. These decisions are based on our analysis of rainfall, runoff bacterial levels and combined sewer activation patterns in previous years.

While it is always a good idea to wash after being on the river, it is particularly important on red flag days. Some boaters choose to stay off the river on red flag days because of elevated bacterial levels.

For further information about CRWA's methodology for water testing, or if you are interested in volunteering to collect water samples, please email crwa@crwa.org.