Ecora was appointed by FortisBC to provide consulting engineering services for the FortisBC Pipeline Corridor (PRI OLI 323) between Princeton and Keremeos in British Columbia. The primary objective was to conduct an Overview Level Rockfall Hazard Assessment as part of the risk management process outlined in CSA Z66219 (2019) Oil and Gas Pipeline Systems.

A previous rockfall risk assessment undertaken in 2013 by others identified potential hazards along the corridor. Significant terrain changes due to wildfires, flooding, and rockfalls necessitated an updated assessment, which will be used by FortisBC to develop land use planning and mitigation strategies.

The project included various stages of investigation, including desktop reviews to helicopter and ground inspections, which were used to evaluate the rockfall hazard analyses along the corridor. The findings of our study enabled FortisBC to review potential mitigation options and mitigation measures.

Risk was determined by defining the Hazard (likelihood of a rockfall event reaching the pipeline), followed by an analysis of its Vulnerability (pipeline depth and rockfall penetration estimation). The Hazard class was assessed by determining rockfall runout lengths using Shadow Angles, validated through ground investigations at hazardous sites. The Vulnerability class was determined by assessing the existing Depth of

Cover (DoC) and calculating penetration depths according to the Pichler Method and Wang and Cavers Method using rockfall simulation software Rocfall2 by Rocscience.

Following the project’s conclusion in April 2024, two rockfall incidents occurred at sites identified as high-risk in accordance with Ecora’s assessment, which is a strong indication of our methodology’s effectiveness as a valuable tool for rockfall mitigation strategies.

The project also had a significant positive impact on the local community by contributing to the well-being of residents and the local economy.

Ecora’s approach for the project Overview Level Rockfall Hazard Assessment PRI OLI 323 – Princeton to Keremeos involved a comprehensive methodology to ensure thorough risk evaluation of the FortisBC asset. The project commenced with a detailed desktop study, utilizing historical data and previous assessments (completed by others in 2013) to identify initial sites of interest.

The risk analysis procedure was undertaken in general accordance with CSA Z662:19 standards, incorporating both qualitative and semi-quantitative methods. The assessment included measuring the DoC of the pipeline at selected locations and evaluating the likelihood of rockfall events impacting the pipeline.

Initial helicopter reconnaissance identified areas with significant rockfall hazards, which were then subjected to detailed ground inspections. This multi-tiered approach ensured accurate hazard identification and vulnerability assessment.

The findings from the risk analysis were categorized into risk groups (A to D), prioritizing sites based on their exposure to rockfall hazards. The project emphasized the importance of continuous monitoring and updating risk assessments, as risk groups can change over time due to several factors including land use and natural events such as wildfires and flooding.

Ecora’s methodical and adaptive approach, combined with advanced analytical tools, underscores the project’s commitment to safety and risk management.

The assessment identified and prioritized rockfall hazards along the PRI OLI 323 pipeline corridor. Using advanced risk analysis methods, including Rocfall2 software, Ecora provided preliminary mitigation options and recommendations for further detailed design. The findings highlighted the need for continuous monitoring and site-specific risk assessments, ensuring the pipeline’s safety and informing FortisBC’s land use planning and mitigation strategies.