The Washington Department of Ecology (Ecology) has fined King County $22,000 for eleven wastewater spills last fall and winter from a pipeline located in Snohomish County.

The spills occurred from November 2012 through January 2013 along approximately 4,000 feet of pipeline between Mill Creek and northern Bothell. This portion of the 43 year-old line is a known pinch point in the system that cannot handle the significant quantities of surface and groundwater that enter from inward leaks during rainstorms.

The discharges may have totaled approximately 10 million gallons. The untreated wastewater flowed into a wetland in Centennial Park and to North Creek. Wastewater also backed up into two homes near Thrasher’s Corner.

“King County took responsibility by responding to each incident, and has taken steps to avoid this problem in the future,” said Kevin Fitzpatrick, Ecology’s regional water quality program manager. “Nevertheless, King County clearly understands that this spill presented environmental risks and the need for remedial action to address possible environmental harm to the wetland and receiving waters.”

The pipeline, called the North Creek Interceptor, carries wastewater from Mill Creek, Thrashers Corner, Canyon Park and Bothell, with flow primarily coming from the Alderwood Water and Wastewater District. King County provides wastewater treatment for cities and sewer districts in parts of southern Snohomish County.

“Our mission is to protect public health and the environment, and taking steps to prevent additional overflows while we complete an upgrade to this aging portion of our regional conveyance system is our highest priority,” said King County Wastewater Treatment Division Director Pam Elardo.

King County plans to accelerate an upgrade and replacement project – originally set for 2017 – to 2016. The county has taken temporary measures and is planning others to avoid overflows and prevent damage to homes if discharges occur in the meantime.

Since the overflows last fall and winter, King County has located and repaired several serious leaks and is continuing more priority work on tightening up the line. To protect homes in the area from potential sewage backups, King County has installed valves that can stop backflows and plans to install pumps to ensure wastewater from the residences flows to the sewer lines.

In case these measures fall short, King County also is designing a temporary system to pump excess flow via an overflow pipe past the area where the discharges occurred. Additional metering will alert King County wastewater system crews when water levels begin to rise in the sewer system. These measures will remain in effect until King County completes the permanent upgrade project.

In response to the incidents last fall and winter, King County provided temporary living accommodations for the occupants of one of the affected homes and professional cleanup and disinfection for both of the damaged houses. The county organized cleanup of the overflow sites after each spill, and posted warnings to the public to avoid contact with the waters. The county paid for and conducted water quality testing to determine when to remove the warnings.

Ecology considered these response measures in setting the penalty amount. Ecology penalties may be appealed to the Washington State Pollution Control Hearings Board.