King County’s marine ambient monitoring program gathers water, sediment, and biological data in the Central Basin of Puget Sound, including associated embayments such as Elliott Bay and Quartermaster Harbor. These data are used to evaluate status and trends of marine water and sediment quality, assess the general health of the Puget Sound marine environment within King County, and provide information for management decisions.

To date, these data have been useful for identifying areas with sediment contamination issues and for highlighting trends (such as decreases) in certain chemicals over time. However, chemistry and physical data alone can only tell us so much about the status of the benthic habitat, and benthos data would be more useful if collected annually. By updating the Marine Sediment Monitoring Program, we aim to preserve our ability to detect trends and monitor the status of sediments in Puget Sound as outlined by the primary goals of the program described below. Additionally, we hope to use these data to support other King County monitoring programs in understanding the biological implications of sediment quality. This tech memo details why changes to the program are needed, provides the updated program goals, and describes what changes are being made to the program to help achieve those goals.