Road hazard
Warmer winters, heavier rains – will your woods roads hold up?
by Mark Partington
Forest roads are a critical component of Atlantic Canada’s asset network, supporting industry, communities, recreational activities, and tourism. The changes in climate that we have been experiencing in recent years are forecast to continue, with an increase in the intensity, duration, and frequency of severe weather events. In other words, we can expect that damaging storms, exceeding what our roads can handle, will occur more often, will be stronger, and will last longer – not to mention the more gradual changes that will also occur, such as warmer winters and drier summers. These changes are expected to have significant impacts on forest road management, such as restrictions on seasonal transportation schedules, increased demands on water crossing infrastructure, and decreased ability to utilize winter (frozen) roads.
Adapting our forest roads to these changes provides an opportunity to minimize negative impacts and reduce the vulnerability of the infrastructure. Structural changes (direct, physical changes to infrastructure) can occur in the short to near term, while operational changes (policies and procedures) typically take longer to implement.
Adaptation practices do not necessarily require significant changes or costs in order to be successful. Soft strategies – such as upgrading rip-rap at water crossings, cleaning ditches, and unblocking culverts – are easy wins. Higher-impact hard strategies – such as implementing winter haul premiums or upgrading road foundations – require more capital and long-term investment.
As we move ahead with upgrading our forest road infrastructure and implementing adaptation practices, we position our roads to become more resilient, thereby creating the capacity to withstand disruption and disturbance. The objective here is not to create infrastructure that is resistant to all hazards, but to create infrastructure that has the capacity to respond and adapt to climate change, while reducing the severity of damage.
VULNERABILITY ASSESSMENT
Roads lacking aggregate, or with fine-grained soils, may not be trafficable in wet, non-frozen conditions. Additional aggregate or the use of geosynthetics may be required, to ensure access as warmer, wetter weather becomes more common. (FPInnovations photos)
Before we implement any adaptation practices, we need to think about four main questions:
1) Are new problems or challenges occurring, as compared to historical practices?
2) What types of infrastructure do we have in our road network?
3) What types of weather events are occurring, or are forecast to occur, that may cause problems?
4) What practices or tools are available that will be effective in creating resilient forest roads?
An important initial step in this process is performing a vulnerability assessment, to identify the probability of certain weather events occurring, and the potential consequences for forest road infrastructure. We can then build a risk and vulnerability profile, highlighting the specific weather events that generate risks to specific types of infrastructure. This will allow us to focus appropriate resources and attention, so we can get the best bang for our buck – which is critical, given the limited time and financial resources available for road upgrades.
Different frameworks are available for performing vulnerability assessments, but a common approach in Canada is the PIEVC (Public Infrastructure Engineering Vulnerability Committee) protocol (www.pievc.ca), which provides a step-by-step process and recommendations on the appropriate information, resources, and reporting factors. FPInnovations has used this protocol in three case studies in British Columbia, and our researchers are currently working on a report to provide recommendations on how to apply this approach to forest roads throughout Canada.
CHALLENGES AND DEFICIENCIES
The case studies highlighted some common challenges and deficiencies with respect to the management of forest roads:
Inventory and performance of infrastructure
Unfortunately, the old adage “You cannot manage what you cannot measure” reflects the general state of forest road infrastructure inventories, performance conditions, and historical maintenance in much of Canada. The lack of accurate inventory of common road assets – such as water crossings (culverts and bridges), cross drains, and signage – is often a serious barrier to understanding the risks that climate change might pose to infrastructure. Many road management plans do not even indicate where various infrastructure exists in the road network, let alone the condition and performance of the infrastructure. Having an asset management plan can significantly improve the ability to achieve resiliency for a road network.
Rainstorm events
As may be expected, precipitation, in the form of rain, is the most critical climatic factor presenting risks to infrastructure. In Atlantic Canada, annual precipitation is forecast to increase by five percent by the 2040s, relative to the 1986-2005 average. It is not the total annual precipitation that is anticipated to have a significant impact on forest road management, but how the precipitation occurs – in shorter-duration, higher-intensity events, i.e., storms.
The average amount of 24-hour extreme precipitation that occurs as 1-in-50-year events (two percent chance of occurring in any given year) in Atlantic Canada is projected to increase by as much as 14 percent by the 2040s. These storm events can have significant impacts on the ability of culverts, bridges, and ditches to handle water flows. Predictable outcomes include washouts and road prism erosion. Today’s infrastructure, designed on the basis of historical climate data, will not be able to withstand the flows and debris generated by forecast increases in storm intensity and duration.
With more extreme rainfall events expected in years to come, short-span bridges may be preferable to culverts, to ensure the resiliency of road networks.
Transportation planning
Warming temperatures in winter and spring may play havoc with the ability to use forest roads, as well as municipal and highway infrastructure. The warming temperatures forecast for all seasons, especially winter, are expected to significantly limit our ability to use the forest road network – if these roads continue to be constructed and maintained only to meet current needs. Roads constructed under the assumption that haul operations will occur in frozen conditions will need to be upgraded, to provide for reliable transportation in the years to come.
Based on FPInnovations’ case studies in British Columbia, it is estimated that spring road closures or load restriction periods may occur 14 days earlier by the 2050s. If this prediction holds true, and if it is an indication of trends in other regions, transportation and harvesting operations planning will be significantly impacted.
The effects of a changing climate – warming temperatures, and changes in precipitation patterns – can be expected to be significant for forest road management. In addition to presenting critical risks to road infrastructure, these changes can be expected to bring important changes to forest operational planning. It will be necessary to adapt our planning, construction, and maintenance practices; the status quo will not be compatible with productive, sustainable forest operations management. Regardless of the extent of climate change, implementing adaptation measures will create better-performing road networks.
On a positive note, many of the necessary actions (ditch and culvert maintenance, effective erosion control, etc.) are already considered best practices for forest road management. However, we need to ensure that they are applied effectively and efficiently. Once this is done, we can focus on the long-term, proactive strategies that are key to developing a reliable, resilient forest road network.
(Mark Partington is a senior researcher in transportation and infrastructure with FPInnovations, based in Pointe-Claire, Québec.)
