Indian Island during King Tide (c) California Sea Grant

Humboldt Bay SLR Vulnerability and Adaptation Planning

Project Documents and GIS Products

Final_HBSLR_Modeling_Inundation Mapping_Report (Northern Hydrology 2015)
Google Earth KMZ Files (Northern Hydrology 2015)
ArcGIS Shape Files (Northern Hydrology 2015)
Final_HBSLR_Project DEM_Development_Report (Pacific Watershed Associates 2014)
Humboldt Bay DEM (developed by Pacific Watershed Associates) – links to Google Drive to download
Final_HBSLR_Conceptual Groundwater Model (Willis 2014)
Humboldt Bay Sea Level Rise Adaptation Planning Project Phase II Final Report (Larid 2015)

Project Background

Climate change is having, and will have, widespread impacts on California’s economy and environment. Sea level rise (SLR) may present one of the greatest risks to coastal communities. In Humboldt Bay region is expected to experience the highest rate of SLR within California due to land subsidence from relatively large tectonic vertical land motions associated with the Cascadia subduction zone. The relative sea level rise projections indicate that , the elevation of average high tide Humboldt Bay could experience rise approximately 49.3 – 173.5 cm (approximate 0.5 – 1.7 meters) by the year 2100 (Northern Hydrology & Engineering 2015; Table 2-9).

The Humboldt Bay Sea Level Rise Vulnerability and Adaptation Planning project, a partnership with Coastal Ecosystems Institute of Northern California; Humboldt Bay Harbor, Recreation and Conservation District; Trinity Associates; Northern Hydrology and Engineering; and County of Humboldt; is funded by the State Coastal Conservancy.  The goals of the project are to identify SLR vulnerabilities and  support informed decision-making and encourage a unified, consistent regional adaptation approach among the jurisdictions around the bay. This project builds on previous work (Phase I) by Trinity Associates completed in January 2013.

Sea Level Rise Vulnerability

A component of the project identified SLR vulnerabilities in Humboldt Bay through a detailed technical study led by Northern Hydrology and Engineering (NHE) and consists of the following work products:
1. SLR hydrodynamic modeling to develop inundation vulnerability maps of areas surrounding Humboldt Bay vulnerable to inundation from existing and future sea levels. A final report is now available along with SLR inundation vulnerability files in Google Earth KMZ files and ArcGIS shape files.
HBSLR Modeling Inundation Mapping Report (Northern Hydrology 2015)
Google Earth KMZ Files (Northern Hydrology 2015)
ArcGIS Shape Files (Northern Hydrology 2015)

2. A seamless topographic/bathymetric digital elevation model (DEM) of Humboldt Bay using the recent 2009-2011 California Coastal Conservancy LiDAR Project Hydro-flattened Bare Earth DEM (California Coastal DEM) and various subtidal bathymetric data sets to support the modeling efforts. Pacific Watershed Associates (PWA) conducted this work in 2014.
Humboldt Bay DEM (developed by Pacific Watershed Associates) – links to Google Drive to download
HBSLR Project DEM Development Report (Pacific Watershed Associates 2014)

3. A conceptual groundwater model to analyze the effects of SLR on groundwater levels and saltwater intrusion in the Eureka-Arcata coastal plain. Dr. Robert Willis conducted this work in 2014.
HBSLR Conceptual Groundwater Model (Willis 2014)

Adaptation Planning

The Adaptation Planning project supports informed decision-making and encourage a unified, consistent regional adaptation strategy to address SLR impacts in the Humboldt Bay region.

This project included the formation of a Humboldt Bay Sea Level Rise Adaptation Planning Working Group (APWG), convened by Humboldt Bay Harbor, Recreation and Conservation District and Humboldt County Public Works Department as co-lead agencies . The APWG is composed of 22 regional stakeholders with land use, land management, resources management responsibilities, or management advisory roles on lands adjacent to Humboldt Bay that are vulnerable to sea level rise impacts. More information about the APWG can be found at http://humboldtbay.org/humboldt-bay-sea-level-rise-adaptation-planning-project.

The Humboldt Bay Sea Level Rise Adaptation Plan prepared by Trinity Associates explores all aspects of sea level rise and adaptation planning on Humboldt Bay, and includes-depth adaptation planning case studies for two critical regional assets that are at risk from sea level rise: agricultural lands and uses and the Highway 101 corridor. Humboldt Bay Harbor, Recreation and Conservation District. The final report was released in February 2015.
Humboldt Bay Sea Level Rise Adaptation Planning Project Phase II Final Report (Larid 2015) 

More Information – Phase I

The Humboldt Bay Shoreline Inventory, Mapping and Sea Level Rise Vulnerability Project was the first phase of this project inventoried and mapped Humboldt Bay’s 102 miles of shoreline.

Download the Phase 1 reports here:
Humboldt Bay Shoreline Inventory, Mapping and Sea Level Rise Vulnerability Assessment Report
Addendum – Humboldt Bay Shoreline Inventory, Mapping and Sea Level Rise Vulnerability Assessment Report

Contact

Jeff Anderson, Northern Hydrology & Engineering

Aldaron Laird, Trinity Associates, Adaptation Planner, Humboldt Bay Sea Level Rise Adaptation Planning Project
, 707-825-8770

Humboldt Bay Harbor, Recreation and Conservation District, Humboldt Bay Sea Level Rise Adaptation Planning Project:
http://humboldtbay.org/humboldt-bay-sea-level-rise-adaptation-planning-project

Jill Demers, Coastal Ecosystems Institute of Northern California

Joel Gerwein, State Coastal Conservancy

Funding

California State Coastal Conservancy’s Climate Ready Grant Program