Seattle DJC.com local business news and data – Architecture & Engineering
April 24, 2025
Climate-resilient future shorelines in Whatcom County
By LILY SCHREDER and RACHEL JOHNSON
Herrera
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Johnson
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In the face of accelerating climate impacts, Whatcom County advances a first-of-its-kind vulnerability assessment and adaptation strategy a holistic look at future flood risk that integrates best-available science with forward-looking county-wide planning. This focus on compound flooding (flooding from the ocean and rivers) and collaboration across jurisdictions not only increases the resilience of the region’s coastal and riverine landscapes, but also provides specialized tools that communities can directly leverage for their own local resiliency planning efforts.
The project, titled Future Shorelines, builds on previous work to assess compound effects of sea level rise and projected changes in coastal and river flood vulnerability, and will result in a county-wide vulnerability assessment, a suite of adaptation tools and insights, a pilot adaptation plan, and forward-looking policy recommendations. Herrera Environmental Consultants (Herrera) is leading the consultant team, which includes Cascadia Consulting Group, MAKERS Architecture and Urban Design and Northwest Hydraulics Consultants.
FLOODING AND EROSION HAZARDS
Like many Pacific Northwest communities, Whatcom County faces increased challenges with flooding and erosion as climate change accelerates. Dynamic coastal and river shorelines naturally experience these processes, but incidents have become increasingly high-profile in recent years.
Floods in 2021 along the Nooksack River displaced thousands of families and required costly, time-consuming transportation repairs. During 2022 and 2023, high tide flooding partially submerged low-lying coastal buildings and significantly damaged infrastructure. Climate change intensifies these risks through rising sea levels, stronger rainstorms and increased river flows.
Whatcom County is planning for low-probability but high-impact scenarios (1% chance of occurrence) while developing flexible adaptation tools for a range of possible outcomes. While it isn’t known exactly when these scenarios will happen, the science is confident that they will occur. Current projections indicate:
• By the 2040s, sea levels could rise by as much as 0.8 feet in Whatcom County (1% probability by 2040; 50% probability by 2060), potentially increasing to 3.3 feet by the 2080s (1% probability by 2080; 50% probability after 2150).
• The Nooksack River’s 100-year flood (event with 1% annual probability) is projected to increase in volume by 1.2 times current levels by the 2040s and 1.75 times by the 2080s.
DEVELOPING PLANNING TOOLS FOR PROJECT PARTNERS
The Future Shorelines project integrates collaborative coastal and river planning efforts to address climate-related shoreline risks, fundamentally relying on a multi-jurisdictional planning approach. The county has convened representatives from the Lummi Nation, the Nooksack Indian Tribe, the Port of Bellingham, and the cities of Bellingham, Blaine, Sumas, Everson, Lynden, Ferndale and Nooksack as well as representatives from the USGS, Department of Ecology, and WA SeaGrant effectively encompassing its communities along the coast and in the Nooksack River floodplain.
Throughout the development of the Future Shorelines project, these partners will ensure their current local planning efforts are aligned, further informing Whatcom County’s final assessment and implementation of resiliency measures.
Through the project’s vulnerability assessment, Whatcom County has gained critical insights regarding geographic areas facing the highest risk of flooding and erosion. Thoroughly understanding these vulnerabilities to coastal storms, sea-level rise, and river flooding enables the team to map at-risk communities and infrastructure, and develop a suite of accessible planning tools. The project will deliver several practical tools to share these findings:
• An interactive StoryMap a web-based platform that combines maps with narrative text and visual elements showing which communities and infrastructure are most vulnerable.
• Data dashboards that will provide users with dynamic summaries of key information displayed in the StoryMap.
• A customizable data explorer tool allowing stakeholders to examine the exposure and vulnerability of specific infrastructure types and natural resources based on their particular interests.
• A workbook of adaptation strategies that communities can modify to their distinct circumstances and needs.
These Future Shorelines planning tools can then be leveraged by partner jurisdictions, which will tailor the tools to meet their unique adaptation challenges and priorities, including considering how to adjust codes and policies to support resilience.
ADAPTATION STRATEGIES FOR THE LONG-TERM
In addition to assessing vulnerabilities, Future Shorelines will result in adaptation strategies to strengthen Whatcom County’s coastal and river communities. Adaptation strategies often fall into four different approaches: avoid (i.e., reduce risk of hazards by not putting development and infrastructure in vulnerable areas), accommodate (i.e., decrease the impacts of flooding and erosion through engineering, design, and restoration), relocate (i.e., move away from hazards through relocating structures), and protect (i.e., delay impacts by preventing flooding and erosion through engineering and design). Adaptation strategies also use different approaches, like policies in land use planning, and building codes, and also structural changes, like habitat restorations or levees.
No matter the strategy, adaptation plans need to be forward-looking, flexible, and realistic. Plans must allow for pairing together different strategies over time. For instance, in the case of a road that is vulnerable to flooding, a near-term approach could include using sandbags during flood events (protect), a mid-term approach could allow the road to flood and be temporarily closed (accommodate), and a long-term approach could involve permanently moving the road (relocate) and restoring the shoreline. While addressing the near term, planning for the long-term is critical since today’s infrastructure investments must withstand climate challenges for the next 50+ years.
As the Future Shorelines project transitions from assessment to planning, Whatcom County will develop a pilot adaptation plan for Birch Bay a community facing significant coastal flood risk and erosion, and already heavily impacted during high tide events. This strategic pilot will identify the most effective adaptation measures for Birch Bay’s specific challenges, and gather community input to inform the development of the plan. Success here will create a valuable template for adaptation planning across vulnerable communities throughout the county.
RESILIENT FUTURE SHORELINES
Whatcom County is set to conclude its Futures Shorelines project in June 2025, establishing a new standard for climate adaptation planning. By integrating future flood and erosion risk projections with detailed geospatial information, the county and its partners will have a clearer understanding of vulnerabilities spanning from present day through the 2040s, 2080s and beyond.
Findings from the comprehensive vulnerability assessment and adaptation strategies will guide crucial decisions about which areas may need additional protection measures, which may need innovative risk-reduction strategies, and which areas may have too high of costs to allow continued growth or development. This project represents Whatcom County’s investment in both critical infrastructure and community planning, adapting shoreline areas to be more resilient and serve residents for generations to come.
Rachel Johnson is a water resources engineer at Herrera who specializes in climate change adaptation planning for watershed, stormwater, and flood management planning projects. Lily Schreder is a marketing specialist at Herrera with a background in marketing and environmental work.
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