The primary objective of the Marine Monitoring Program is to provide an understanding of water and sediment quality, food web lower trophic levels, and environmental conditions in King County receiving waters, including areas near discharges from the County’s wastewater treatment plants, combined sewer overflow outfalls, and CSO wet weather treatment stations. The County maintains a long-term dataset for a variety of water quality focused parameters. Data have been collected at some monitoring locations for over 50 years. These data provide insight into both short and long-term variations and form a basis from which water quality conditions can be assessed on multiple temporal and spatial scales.

The Marine Conditions Report Series consists of 13 reports that provide results from multiple sampling components monitored between 2008–2019. The reports include: an overview of the Marine Monitoring Program (includes climate data), offshore and beach water temperature and salinity, water clarity, dissolved oxygen, bacteria, offshore and beach water nutrients, chlorophyll and pheophytin, phytoplankton, zooplankton, sediment (chemistry and benthic infauna), and clam tissue.