We have a surface water quality monitoring program to assess watershed health. A watershed is an area of land where all the water that is under it or on it drains to the same place. The four major watersheds in Pierce County drain to Puget Sound. Pierce County regularly monitors water quality in all four watersheds. Want to know where the water from your neighborhood goes? Check out Where Does Your Water Go.
Surface water monitoring includes:
Collecting water quality samples in over 50 streams on a monthly basis. The data is used to create a Water Quality Index (WQI) - a way to monitor water quality trends in streams over time.
Collecting stream insects (benthic macroinvertebrates) from over 30 streams per year. This data is used to create a Biological Index of Biotic Integrity (BIBI) - a way to assess overall stream health based on which insects are able to survive in the stream.
We issue an annual Surface Water Health Report Card on the health of surface water quality in each major watershed. The report card grades a number of streams on a scale of "A" to "F" based on a combination of WQI scores and BIBI scores. These factors combined provide a realistic overall understanding of stream health, and help direct our clean up efforts. The report card also includes an assessment of some lakes in the county.