Starting as early as April 10, field crews will collect soil samples to map the boundaries of wetlands along the existing pipeline (see map below). The soil samples will inform design. Private properties will not be surveyed or accessed during this fieldwork. 

Crews will use hand shovels to dig a small hole in the ground and record observations of soil, vegetation, and hydrology to identify wetlands. Any confirmed wetlands will be marked by placing pink flags. Crews will fill and restore all work areas. This work is expected to be completed in one day and take approximately 30 minutes at each site. Depending on site conditions, the work may take an extra day and will be completed by April 15. This work may reoccur quarterly. 

• Crews will collect samples along either side of the existing pipe and will start from the southern end. Crews will begin collecting samples during the day on April 10 to 15. 

• The schedule and sequence for wetland sampling may change. Please check the project website for updates on the sequence and work schedule.  

Black Diamond is one of the fastest-growing communities in the Puget Sound region. In 1992, in collaboration with King County, the City built a regional sewer line to serve the area’s much smaller population at the time. Today, we need to upgrade the existing sewer line because it’s reaching capacity. This project will explore options to increase capacity for 6 miles of regional sewer pipe. Upgrading the pipe will help King County serve the community's wastewater needs until the year 2070. The upgrade will also ensure reliable wastewater service to Black Diamond’s homes and businesses.