|Citation||Symonds, B et al. 2013. Review of landslide management in British Columbia. BC Ministry of Forests, Lands and Natural Resource Operations.|
|Abstract/Description or Keywords||In June and July 2012 numerous landslide events occurred across southern British Columbia. Most
events occurred in the backcountry, without significant negative impacts to infrastructure or people.
However, some populated and developed areas in the fore country or valley bottoms experienced
significant damage to private property and public infrastructure. A landslide at Johnsons Landing in the
Kootenays resulted in four fatalities.
On July 17, 2012 the Minister of Forests, Lands and Natural Resource Operations requested a review of
how landslide hazards are managed in BC and the circumstances of the most damaging events of 2012
to identify lessons to be learned. The review examined the management of landslide hazards under the
four pillar approach of preparedness, mitigation, response and recovery. The review found that
generally the greatest effort by government staff and other stakeholders is directed at preparedness as
success in preparedness sets up and reduces pressure on the remaining three pillars.
Natural hazards, of which landslides are only one type, occur in most areas of BC. The province is
typically steep and with limited land readily amenable to development. Long-established communities
are exposed to some risk of hazards from flooding and landslides. Both small and large landslide events
have impacted numerous communities across the province for over 100 years, and many lessons have
already been learned in managing new developments. Previous reviews on a fatal landslide in North
Vancouver in 2005 and the Testalinden Dam Failure near Oliver in 2010 have provided
recommendations and spurred some new initiatives in the province. Recommendations herein are
made to build on these previous reviews.
The most damaging events in 2012 occurred near Sicamous, Johnsons Landing and Fairmont Creek.
Each of these events had different circumstances, however high precipitation and previous winter high
snowpacks were common contributing trigger mechanisms. The Sicamous and Fairmont Hot Springs
sites were known debris flow or flood hazard areas with existing management tools in place designed to
mitigate the risks. In Johnsons Landing, a landslide was initiated on relatively pristine steep terrain
above the small remote community.
Recent climate change models project that British Columbia will experience more frequent and severe
rainstorm events and years with higher snowpacks at high elevations. The models also project earlier
onset of freshets and more prevalent summer droughts and wildfires. These projections are in line with
observed trends over the past several decades and have the potential to increase the likelihood of
landslides occurring. Given ever-increasing pressure for more development in areas potentially
exposed to landslide hazards, these projections will need to be taken into consideration in the
preparation and planning of measures to reduce the landslide risks to existing and future developments.
The best practice to reduce landslide hazard risks to people and infrastructure is to be aware of and
avoid the hazard altogether or reduce exposure and risk. Landslide and flood hazard maps have been created in the past to help inform development decisions however, the management of the information
is relatively uncoordinated making it difficult to access. Furthermore, resources for mapping programs
have been reduced over time. Key to preparedness for landslide (and flood) hazards is a modern and
comprehensive all-hazard mapping program.
As noted above, mapping programs help to identify developments and resource use proposals which
should be studied through more detailed hazard mapping and assessments. Some guidelines for
landslide and terrain stability assessments have recently been published in collaboration between
government and professional associations in BC. However, outstanding issues of reaching agreement on
a common definition of what constitutes safe and acceptable risk and further clarifying the scope of the
assessments require further work and direction.
Local and provincial government staff and the public would benefit from greater awareness and training
into landslide hazards near their communities. Currently local governments are required by law to write
and maintain emergency response plans for events such as landslides and other natural hazards as part
of their emergency preparedness roles. The proper application of mapping and hazard information to
support timely and effective early response depends on users’ competence and field recognition skills.
Preparedness for various types of emergencies is generally well set up in British Columbia however the
landslide preparedness appears to be somewhat slight and recommendations have been made to
improve in this regard.
Where new or existing developments and infrastructure are identified as being at risk of landslide
hazards, various physical methods can be employed to mitigate the risks. Such measures include the
use of deflection berms and catch basins, as well as prediction and early warning systems. These
approaches have been implemented in British Columbia and worldwide, however high costs and difficult
implementation and maintenance has generally meant that these methods are only used as a last resort
in densely populated areas where there is a high known probability of damaging landslides or other
natural hazards. In rural areas with low population densities, local governments may be challenged to
acquire the funding to construct and assume responsibility for the long term ownership of operation and
maintenance of the works. The presence of old and unmaintained structures as well as requirement for
some new structures presents liabilities to public safety and to governments. Recommendations have
been made to address the funding models to work around these challenges.
The Emergency Program Act details the roles and responsibilities of local governments and authorities,
and provincial agencies in response to emergency events. Typically the various groups work together
with shared responsibility to provide optimum response and service to communities and individuals.
For example, in the Kootenay Boundary Region, long standing relationships between staff in provincial
ministries and local governments have resulted in landslide and flood event response rosters which are
updated annually with specialist staff and a phone contact list, to provide rapid response time of the
most local and appropriate individuals in a coordinated fashion. This system has proved to be effective
in responding to many landslide and flood emergencies. Recommendations are made to continue
efforts to increase public awareness of who to contact during emergencies, maintain the necessary
emergency responder training, and ensure that all regions of the province maintain coordinated
landslide and flood response rosters.
Disaster Financial Assistance is made available in certain cases under established guidelines and
thresholds to support response and recovery efforts. As well,
|Sub-watershed if known|