Chapter 10: Adaptation for climate change and weather extremes

Resilient Infrastructure Engineering Design

Climate change impacts can result in significant damage to resource road infrastructure which is disruptive to access and costly to repair. Although storms are a normal occurrence, climate change has caused storm events to happen more frequently and with increased intensity. Storm flood damages, that appear to be occurring frequently, on public and resource roads are illustrative examples. These more frequent and more intense storm events are impacting communities across the province and are causing damage to infrastructure, property, resources and ecosystems. Current climate projections predict that this situation will persist and potentially worsen in the decades to come.

Given the potential for climate change to impact Forest Service Road (FSR) infrastructure in BC, it is prudent and necessary to develop policies and guidance for incorporating climate adaptation into engineering designs and activities. Preparing for future conditions, including those potentially influenced by climate change, when considering the design, construction, operation, and maintenance of infrastructure is critical to protecting the integrity of the FSR system and the investment of taxpayer dollars.

The guidance in this chapter is intended to assist Forest Professional and Engineer practitioners in meeting their professional obligations to consider and mitigate the potential impacts of climate change on resource roads and infrastructure.

The design life of FSR infrastructure is frequently long, and maintenance may be required for many decades. As an integral part of our provincial transportation infrastructure, FSR’s are already exposed to a range of stressors such as deterioration due to aging, land-use changes, population growth and environmental impacts; many of which are directly influenced by climate. An objective is to design roads, crossings and drainage structures on FSR’s to be climate resilient for their intended service life, withstand deterioration over time and potential site impacts such as: floods, wildfires, landslides, geologic subsidence, earthquakes, rock falls, avalanches, snow loading, wind loading, debris passage, debris flows/debris floods, ice forces, extreme temperature variations, and storms of various intensities, etc. While existing transportation infrastructure has been designed to handle a broad range of impacts based on historic climate, preparing for changes in average climate conditions, weather extremes and other climate related events is also essential. This preparation is critical for protecting transportation infrastructure as well as current and future investment.

Climate change adaptation is the practice of implementing actions to address projected climate changes and impacts. Professional associations such as Engineers and Geoscientists BC (EGBC) and the Association of BC Forest Professionals (ABCFP), expect that their members consider the potential impacts of climate change and to include climate change adaptations in their work. The BC Professional Governance Act strengthens the requirement for members of these associations to complete professional and defendable work.

Many infrastructure parameters, such as location, type, traffic volume, and design life will determine the climate change and extreme weather event analysis required. The level of effort for consideration should be commensurate with the level of risk. For example, design of a small temporary portable bridge may only require a summary analysis, while a high use critical access long span, high industry and public use, permanent bridge will require a more rigorous analysis.

There are currently many climate change adaptation tools available to transportation infrastructure designers and some Climate Adaptation and Vulnerability Analysis Resources are provided below. Utilizing these tools along with local knowledge and professional judgement to adjust designs to a projected future condition that will result in more resilient infrastructure and more efficient use of resources is the challenge and responsibility of all resource professionals.

In general, for FSR engineering design projects, the following should be considered for each project by the designer:

Reasonable consideration of impacts of changes in climate conditions, weather extremes and future climate-related events that could impact the project (including new, rehabilitation and maintenance projects)
Assessment of infrastructure and climate vulnerability and risk for the design life of components, indicating relevant information Design that incorporates information, analysis and projections of the impact of future climate change and weather extremes
Development of practical and affordable project design criteria which takes adaptation to climate change into account and addresses identified vulnerability and risks, and
Documentation on the project file that summarizes engineering design parameter evaluation and modification for adaptation to climate change.

The following steps provide guidance for infrastructure designers to consider the impacts of climate change.

Evaluate vulnerability of project (At the concepts stage):
- Identify planned lifespan of infrastructure
- Based on infrastructure lifespan, identify a timescale into the future to analyse
- Use risk assessment methods and climate information from available sources, consider available local and indigenous knowledge as may be appropriate and available
- identify the design components at risk from the impacts of future climate change and weather extremes over the extended project design life
- summarize changes in temperature, precipitation and other climatic variables over the expected project design life
- Record projected changes in temperature, precipitation and other climate factors from initial analysis and anything significant from sensitivity analysis
- Assess how projected climate changes could impact infrastructure or site in question: usage types and frequency; increase in clear flow discharge; freeze/ thaw; rain on snow event; erosion; probability of debris flow or landslide, (identify what ‘failure’ would look like at this site)
- identify the risks to the project design components from these projected climate changes and summarize the risks (suggested Climate Change Design Criteria Sheet for Climate Resilience)
- Consider if/ how probability of above events is increased due to projected climate change impacts; ie: probability of failure

Evaluate consequence of project ‘failure’
- Identify resources at risk from failure
- Use vulnerabilities, probability of failure and consequence of failure to identify the impact of climate change factors on risk of project.

Identify changes or adaptations that can be made to project design to reduce identified risk.
- The project designer will develop adaptation design strategies to address climate change risks for the project
- Based on evaluation of future climate change effects and impacts, the project designer will develop a project-appropriate set of design criteria for event preparedness and resiliency
- Implement the developed design criteria into the project
- Engineering design parameter evaluation and modification for adaptation to climate change should be summarized and listed (suggested Climate Change Design Criteria Sheet for Climate Resilience)
- Document above analysis to show that potential impacts of climate change were considered in a professional and defendable manner.
  - Sample documentation approach provided in Appendix 4-1.