Water Stewardship Information Sources
| Citation | Clague, JJ, Hungr, O, Morgenstern, NR and VanDine, D. 2015. Cheekye River (Ch'kay Stakw) and Fan Landslide Risk Tolerance Criteria: Report of the Cheekye Expert Review Panel #2. Prepared for FLNRO, Squamish Nation and District of Squamish. |
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| Organization | FLNRO |
| URL | http://squamish.ca/assets/Cheekye-Panel-2-Final-Report-JUne-6.pdf |
| Abstract/Description or Keywords | In March 2015, the Province of British Columbia, Squamish Nation and its Partnership, and District of Squamish collectively selected and appointed an independent Cheekye Expert Review Panel (Panel #2). Panel #2 was instructed to use the results of the 2013-2014 Cheekye River and Fan Expert Review Panel (Panel #1) Report (Clague et al. 2014) to review current worldwide landslide risk tolerance criteria and, from its collective experience, provide advice with respect to: Task 1: landslide risk tolerance criteria for existing and proposed new development on Cheekye Fan; Task 2: current levels of individual and societal risk from landslides on Cheekye Fan; Task 3: individual and societal risk reduction that might be achieved through mitigation, given existing and proposed new development; and Task 4: whether individual and societal landslide risk tolerance criteria can be applied across the District of Squamish or solely to Cheekye Fan. Landslide risk tolerance criteria are thresholds, beyond which estimated risk from landslides is considered unacceptable. This Report summarizes Panel #2’s findings, opinions, and recommendations. The focus of Panel #2 was on risk to life. In order to live in mountainous areas, individuals and society must be prepared to tolerate some risks from landslides. Small landslides occur frequently on steep slopes. Large landslides occur much less frequently, but can have much greater effects. It is not practical to reduce these landslide risks to zero. However, every day, individuals live with risks of dying. The side bar to the right provides examples of an individual’s annual risk of dying from some everyday activities and causes. Individual and societal risks are discussed further in Sections 3.3 and 3.4 of this report. A number of jurisdictions in the world have established landslide risk tolerance criteria. Although experts can provide valuable input for determining landslide risk tolerance criteria, stakeholders and jurisdictional decision-makers ultimately have to select, by means of an appropriate public process, appropriate risk evaluation parameters (hazard probability, and landslide volume and/or peak discharge) for a particular situation or jurisdiction. This selection has to balance risks from landslides with societal values. Societal values include things such as public safety, affordable residential land, and return on investment. Once landslide risk tolerance criteria have been established and appropriate risk evaluation parameters have been selected, communities can choose a number of options to meet the criteria. For example, communities can choose not to develop areas that could be affected by landslides, or they can choose to construct some form of engineered mitigation structure, or a combination of options. The purpose of this report is to provide expert opinions and recommendations to help stakeholders, including citizens, and jurisdictional decision-makers, better understand landslide risk and make informed decisions about landslide risk tolerance criteria, hazard probability, and landslide volume and/or peak discharge for existing and proposed development on Cheekye Fan. Landslide risk is the combination of the probability that a landslide will occur (hazard probability) AND the expected consequences if it does occur (see side bar to the right for a brief explanation of risk). Section 3 of this report reviews risk and risk assessment. Section 4 of this report reviews the development of risk tolerance criteria throughout the world, from the industrial and nuclear engineering fields, to dam safety, and finally to landslides. Because hazard probability is more commonly used than risk for the management of landslides in most jurisdictions around the world, landslide hazard probability tolerance criteria are also reviewed. Based on its review of landslide risk tolerance criteria throughout the world, Panel #2 has determined that only Hong Kong (in 1998), the District of North Vancouver, BC (in 2009), and the Town of Canmore, Alberta (in 2014) have successfully used quantitative risk assessments for landslides. Quantitative risk assessments require that landslide risk tolerance criteria be established in the respective jurisdictions. The District of North Vancouver and Canmore based their criteria on those of Hong Kong. |
| Information Type | report |
| Regional Watershed | Howe Sound & Sunshine Coast |
| Sub-watershed if known | Cheekye River |
| Aquifer # | |
| Comments | |
| Project status | complete |
| Contact Name | John Clague |
| Contact Email | [email protected] |