to protect and preserve the ponds and rivers of the state-designated Herring River Area of Critical Environmental Concern (ACEC), encompassing 4450-acres in southern Plymouth and Bourne. Our ACEC includes 11 ponds (the largest, Great Herring is 376 acres), two rivers, numerous freshwater wetlands, productive cranberry bogs, an important active river herring run, and 250 acres of protected open space. We identify issues and their causes, and work to rectify them through citizen science, education, and coordination with town officials. We raise awareness and build a volunteer/member base to both monitor the watershed and act for its protection. Through water quality sampling we identified a storm water runoff issue, and worked with the town, leveraging support for a $250,000 grant- and town-funded retention and bio-remediation (rain garden) solution. We reach out to all ACEC residents to adopt best practice watershed stewardship actions at home (and applicable anywhere).