HUMBOLDT BAY SEA LEVEL RISE ADAPTATION PLANNING PROJECT Funded by the State Coastal Conservancy Aldaron Laird Project Planner

ADAPTATION PLANNING WORKING GROUP State Coastal Conservancy Coastal Ecosystems Institute of Northern California Humboldt Bay Harbor, Recreation and Conservation District Humboldt County City of Eureka City of Arcata California Coastal Commission, North Coast District Wiyot Tribe Department of Fish and Wildlife Humboldt Bay National Wildlife Refuge Bureau of Land Management U.S. Fish and Wildlife Service

MOSAIC OF COASTAL PLANNING AUTHORITIES Coastal Commission: Retained and Federal Humboldt County City of Eureka City of Arcata Harbor District

ADAPTATION PLANNING GOAL To support informed decision-making and encourage a unified, consistent regional adaptation strategy to address impacts associated with sea level rise in the Humboldt Bay region.

SEA LEVEL RISE ADAPTATION PLANNING PROCESS ASSESSPLANIMPLEMENT  2012 California Climate Adaption Guidelines  2012 Adapting to Sea Level Rise: A Guide for California's Coastal Communities

PHASE I ASSESS EXISTING CONDITIONS Shoreline Inventory & Mapping Trinity Associates McBain & Trush Northern Hydrology & Engineering Tuluwat 8.94’, 2010

PHASE II VULNERABILITY ASSESSMENT & ADAPTATION PLANNING Coastal Ecosystems Institute of Northern California Humboldt Bay Harbor Recreation and Conservation District Humboldt County Public Works Department Northern Hydrology & Engineering & Trinity Associates

Historical Conditions % Open Bay 40% Salt Marsh 60 miles of Shoreline

Current Conditions 90% Open Bay 10% Salt Marsh (-9,000 acres) 102 miles of Shoreline 75 % (77 miles) Artificial 25% (26 miles) Natural

Dike = 53%, 41 miles Dike = 53%, 41 miles Railroad = 14 %, 11 miles Railroad = 14 %, 11 miles Shoreline Structure

Exposed = 9 miles Exposed = 9 miles Vegetated = 65 miles Vegetated = 65 miles Fortified = 27 miles Fortified = 27 miles Shoreline Cover

Shoreline Elevations Mean Monthly Maximum Water & 2012 LiDAR Elevations

PHASE II VULNERABILITY ASSESSMENT & ADAPTATION PLANNING Flooding from the failure of shoreline structures or sea level rise is the primary exposure to Humboldt Bay communities  2012 California Climate Adaption Guidelines  2012 Adapting to Sea Level Rise: A Guide for California's Coastal Communities

PHASE II VULNERABILITY ASSESSMENT & ADAPTATION PLANNING  Shoreline Inventory and Mapping  Inundation and Groundwater Models  Potential Inundation Area Maps  Case Studies of Selected Critical Assets  Annual Public and Stakeholder Meetings

CURRENT TIDEWATER FLOODING CURRENT TIDEWATER FLOODING King High Tide 8.94’, 2010

VULNERABILITY & RISK ASSESSMENTS EXPOSURE: Where SENSITIVITY: What IMPACTS: How ADAPTIVE CAPACITY: Responses RISK & ONSET: Urgency ECONOMIC CONSEQUENCE: Prioritize

EXPOSURE: Where

A HISTORICAL LEGACY A HISTORICAL LEGACY Dike Cover & Elevation

Shoreline Vulnerability Rating HIGHLY VULNERABLE = 59.0 miles HIGHLY VULNERABLE = 59.0 miles MODERATELY VULNERABLE = 28.3 miles MODERATELY VULNERABLE = 28.3 miles LOW VULNERABILITY = 14.0 miles LOW VULNERABILITY = 14.0 miles

 Create 100 year Record of Predicted Tidal Elevations  Create Inundation Model and Maps (EC, 1, 2, 3 & 6 feet sea level rise & 100 year flood)  Create Groundwater Elevation Model and Maps (EC, 1, 2, 3 & 6 feet sea level rise) VULNERABILITY ASSESSMENT MODELING Jeff Anderson Northern Hydrology & Engineering

EXISTING CONDITIONS Potential Flood Area: Shoreline Failure

EXPOSURE: Where SENSITIVITY: What

A. Communities: King Salmon King Salmon B. Facilities & Services: 1.Water and Wastewater City of Eureka Wastewater City of Eureka Wastewater City of Arcata Wastewater City of Arcata Wastewater 2. Energy 3.Transportation Highway 101 Corridor Highway 101 Corridor 4. Communications CRITICAL ASSETS AT RISK APWG Selected for Adaptation Planning Case Studies That affect the greatest number of people in the Humboldt Bay region

KING SALMON

HIGHWAY 101 TRANSPORTATION CORRIDOR

 Structures  Land Uses  Private Property  Historical/Cultural/ Archeological Resources  Hazardous Material Sites  Contaminated Lands  Natural Areas and Natural Resources OTHER ASSETS CATEGORIES

EXPOSURE: Where SENSITIVITY: What IMPACTS: How

SECONDARY IMPACTS: A. Flooding  Shoreline Erosion-Breaching  Shoreline Overtopping  Rising Groundwater B. Salt Water Intrusion PRIMARY IMPACT: SEA LEVEL RISE

SHORELINE FAILURE by EROSION SHORELINE FAILURE by EROSION King High Tide and High Winds Breach Dike Photo Credit; Times Standard 9.51’, 2003

SHORELINE FAILURE by OVERTOPPING SHORELINE FAILURE by OVERTOPPING King High Tide and Storm Surge 9.49’, 2006

RISING SEA LEVELS & RISING GROUNDWATER

EXPOSURE: Where SENSITIVITY: What IMPACTS: How ADAPTIVE CAPACITY: Responses

ADAPTIVE CAPACITY Land Use Policies and Regulations Structure and Infrastructure Projects Natural Systems Protections Public Education and Awareness Financial Abilities

EXPOSURE: Where SENSITIVITY: What IMPACTS: How ADAPTIVE CAPACITY: Responses RISK & ONSET: Urgency

Long-Term Average King Tide 8.78’ Average King Tide 8.92’ (Mean Monthly Maximum High Tide 7.74’)

RELATIVE SEA LEVEL RISE (North Spit Sea Level Rise + Subsidence Rate = 18.6” Sea Level Change per Century, Russell & Griggs, 2012)

EXPOSURE: Where SENSITIVITY: What IMPACTS: How ADAPTIVE CAPACITY: Responses RISK & ONSET: Urgency ECONOMIC CONSEQUENCE: Prioritize

MAGNITUDE OF CONSEQUENCE Economic importance or value of assets affected by:  Flooding  Rising Groundwater  Salt Water Intrusion

PRIORITIZE ADAPTIVE NEEDS IDENTIFY STRATEGIES PRIORITIZE STRATEGIES PHASE & IMPLEMENT DEVELOP & IMPLEMENT ADAPTATION STRATEGIES

BASIC ADAPTATION PLANNING STRATEGY BASIC ADAPTATION PLANNING STRATEGY We cannot manage or protect the shoreline parcel by parcel or jurisdiction by jurisdiction, we need to address entire hydrologic units and the entirety of Humboldt Bay.

ADAPTATION STRATEGIES Land Use Policies and Regulations Structure and Infrastructure Projects Natural Systems Protections Public Education and Awareness

CITY OF ARCATA Wastewater Facility Dike Rehabilitation $900,000.00/mile

Tsunami and FEMA Flood Zones & 2 Meter Sea Level Rise Inundation Area 3.0 meters 6.0 meters 2.0 meters

THANK-YOU