Sea Level Rise

Sea Level Rise Adaptation Plan for Humboldt Bay/Eureka Slough Area (2018-2020)

Humboldt County received funding from the Caltrans Adaptation Planning Grant program to support the preparation of a sea level rise adaptation plan for the Eureka Slough hydrologic sub-unit of Humboldt Bay. This area includes segments of Highway 101, county and city roads, railroad, and the future Humboldt Bay Trail, along with Murray Field airport, utility transmission lines (gas, electrical, water), wastewater pump stations, and a mix of industrial, commercial, residential, agricultural and wildlife land use. Due to ground surface elevations, exposure to wind waves, and the condition of levees and embankments, this area is especially vulnerable to flooding hazards, with vulnerability expected to increase due to the progressive rise of sea levels.

The Eureka Slough area spans multiple municipal jurisdictions, and a variety of stakeholders including City of Eureka, HCAOG, Caltrans, North Coast Railroad Authority, California Department of Fish & Wildlife, the Humboldt Bay Harbor, Recreation and Conservation District, Humboldt County Farm Bureau and Pacific Gas & Electric Company desire to participate in regional collaboration for adapting to sea level rise. The City of Eureka and the Humboldt County Association of Governments were subapplicants for the grant, which is funded through Senate Bill 1, the Road Repair and Accountability Act of 2017.

The project will prepare an adaptation plan that identifies the specific flooding vulnerabilities within the planning area and develops adaptation project concepts, with an emphasis on stakeholder engagement, multi-benefit goals, best available scientific information, cost-effectiveness, and strategic planning. The project is expected to be completed in December 2020.

March 2020 Workshop


Presentation Slides

Planning Framework Summary

Study Area Map

Hazard Scenario Summary Table

Scenario 3 Case Study:

•    Narrative

•    Exhibit HS 3-1

•    Exhibit HS 3-2

Scenario 5 Case Study:

•    Narrative

•    Exhibit HS 5-1

•    Exhibit HS 5-2

Project Documents

Scope of Work

Project Area Map

Existing Conditions Map Set (92 MB)

Humboldt Bay/Eureka Slough Sea Level Rise Presentation – Humboldt Bay Symposium (April 2019) (12 MB)

Jacobs Avenue Levee Informational Meeting Presentation (May 2019) (5.5 MB)

Humboldt Bay Sea Level Rise Adaptation Planning Project (2010-2015)

The Humboldt Bay Sea Level Rise Adaptation Planning Project was active from 2010 through 2015 and conducted two phases of regional collaborative planning with funding from the California State Coastal Conservancy.


Caltrans District 1 Climate Change Vulnerability Assessment – Main Document (December 2014) (PDF 3 MB)

Caltrans District 1 Climate Change Vulnerability Assessment – Appendices (December 2014) (PDF 22 MB)

Humboldt Bay Area Plan Update