Arcata Wastewater Treatment Plant Improvement Project


September 1, 2022

The Commission approved the Arcata Wastewater Treatment Facility improvement project. The facility is located on the edge of Arcata Bay in an area consisting of former tidelands and there is sensitive habitat on site. The facility has exceeded its expected life and is in need of upgrades. Those include a new ocean outfall, a new UV disinfection system, new wastewater piping, new electrical infrastructure and others. The Commission approved the project on an interim basis of 30 years to allow for continued operation and to protect water quality in Arcata Bay. Given the facility’s vulnerability to rising seas, the interim authorization will ensure that the City can implement alternative long-term adaptation approaches and consider relocating the facility out of harm’s way. The City is required to complete a Coastal Hazard Adaptation and Implementation Plan within five years. The City was not supportive of the interim duration of the permit, but local advocates including Humboldt Baykeeper, North Coast Environmental Center and Surfrider Foundation were. The Commission unanimously approved the permit as recommended by staff.

Why You Should Care

The new facility will have a 30-year lifespan, during which time sea level is predicted to rise 3 feet in the Humboldt Bay area, according to OPC’s H++ scenario recommended for critical public infrastructure. The relative rate of sea level rise in and around Humboldt Bay is twice the state average due to tectonic subsidence. Even yet, the City has not seriously considered relocating the facility to a less vulnerable location. Instead, the City was on a trajectory to armor the facility in place, raising levees around it and along the access road to create a peninsula without considering the impacts related to coastal resources. Building wider, taller levees will require a larger footprint and yet will do nothing to prevent groundwater from rising. In addition to risks related to rising sea level and groundwater, alternatives to continuing to discharge to Humboldt Bay should be considered in the long term. While the facility was considered cutting edge 40 years ago, today we know that even with these improvements, PFAS, endocrine-disrupting pharmaceuticals, and many other pollutants harmful to aquatic life pass through wastewater treatment systems.


Pro-Coast Vote

Anti-Coast Vote

The 30-year permit allows time to analyze relocation and other alternatives to shoreline armoring while improving water quality. Condition 10 makes clear that the City cannot rely on shoreline armoring without analyzing alternatives that may be in the best interests of the community, including the taxpayers and ratepayers who will be funding these improvements. Commissioners agreed with the staff recommendation and unanimously approved the permit.

Organizations Opposed

Humboldt Baykeeper, NEC, Surfrider Foundation

Decision Type

Coastal Development Permit

Staff Recommendation

Approval with Conditions

Coastal Act Policy