Sea Level Rise

Sea Level Rise Vulnerability and Risk Assessment Project

The City of Arcata was awarded a California Coastal Commission Local Coastal Program (LCP) Local Assistance Grant for conducting a sea level rise vulnerability and risk assessment and capital improvement project adaptation plan for coastal resiliency planning along Arcata’s shoreline. 

The project will help the City to better understand vulnerabilities to sea level rise and flooding along Arcata’s shoreline and develop adaptation strategies that reduce or accommodate the flooding and erosion associated with sea level rise. The planned study will involve more detailed hydraulic modeling than has previously been conducted for the Arcata shoreline, considering sea level rise, as well as the compounding effects of potential wave action, rainfall, and stormwater flows. The study area extends from McDaniel Slough to Washington Gulch (Brainard Slough). The project includes the following tasks: 1) Develop hydraulic model of the study area, 2) Conduct coastal exposures and vulnerability and risk assessment considering potential flooding from tidal still water, wave action and rainfall, 3) Develop an adaptation plan for capital improvement projects, and 4) Update the City’s LCP. The adaptation strategies will consider both the location of assets as well as the condition, age, and proximity to other natural and built landscapes at risk to determine if there are opportunities for multi-benefit strategies that address both climate adaptation as well as long term capital planning. The project started in the summer of 2023 and is scheduled to be completed in early 2026. 

Sea Level Rise Report & Appendices (Updated June 11, 2025)  

Please be patient when opening up these files, some of them are quite large! 

• City of Arcata - Sea Level Rise Vulnerability & Risk Assessment Base Report
• Appendix A - Coastal Flood Assessment 
• Appendix B - Hydraulic Modeling Memorandum 
• Appendix C - Flood Pathways Maps
• Appendix C - Transportation Infrastructure Flooding Maps 
• Appendix C - Utility Infrastructure Flooding Maps 
• Appendix D - Risk Assessment Maps 

In addition to the City’s Sea Level Rise Vulnerability and Risk Assessment Project, we’re conducting long range planning for the Arcata Wastewater Treatment Facility, more information is available here: https://www.cityofarcata.org/1099/Arcata-Wastewater-Treatment-Facility-Fea.

The City Council and Planning Commission hosted a panel of experts representing national, state, and local perspectives on sea level rise adaptation on Tuesday, March 28, 2023, at 6:00 p.m. The meeting was held in the City Council Chambers and it was broadcasted on public access tv, the City’s YouTube channel, and zoom. Please find the agenda at http://arcataca.iqm2.com/Citizens/default.aspx and choose the City Council under the “Meeting Group” dropdown box. 

The recording of the session can be viewed here.