For more than 20 years, Snohomish County and partner organizations have been working to protect and restore water quality in the Stillaguamish River. These water quality restoration efforts have contributed to the reopening of 4,950 acres of Port Susan and South Skagit Bay commercial shellfish growing areas (PDF).
Even with these gains, various portions of the Stillaguamish River watershed continue to exceed Washington State water quality standards for fecal coliform bacteria. The bacteria comes primarily from warm blooded animals including humans, livestock, pets, and wildlife, and is an indicator of the presence of other disease causing organisms. Contact with water or consumption of shellfish polluted with fecal coliform bacteria can cause illness such as upset stomach, diarrhea, and ear infections or more serious disease such as hepatitis and salmonella.
Source: Citizen's Guide to Understanding and Monitoring Lakes and Streams. Department of Ecology, May 2005
Water quality monitoring helps to identify sites with higher levels of pollutants where more targeted pollution control efforts should be focused. It can be challenging to control fecal coliform from wildlife, but bacterial pollution caused by people and domestic animals can be managed through efforts such as the PIC Program.