Charles River Basin Water Quality Flagging Program

Flagging Program Project Background Subscribe to daily water quality report Map of Flagging Sites  Muddy River Rain Gauge (Operated by USGS) 1998-2005 Historical Data  Monthly Water Quality Data Development of the bacteria prediction model for the Charles River (PDF) Watch a video of the flagging program (Get Real Player here) Flagging program home

Thank you for your interest in Charles River Watershed Association's summer water quality flagging program.

CRWA's Flagging Program presents the daily flag colors of the river's health, which signify whether or not the river is safe for boating at nine boating locations from Watertown to Boston. Flag colors are based on bacteria levels and blue-green algae counts. CRWA estimates bacteria levels using a model that takes into account antecedent rainfall conditions and if available, the previous day's bacteria sampling results. CRWA typically collects river samples for bacteria twice a week. Blue-green algae monitoring is conducted at least every two weeks.

For a project description click here.

a blue flag indicates suitable boating conditions

A yellow flag indicates inconclusive data to predict possible health risks

a red flag indicates potential health risks