Avocet Pde OPW - App E Slope · OPW20/0092

AUSTRALIAN GEOGUIDE LR7 (LANDSLIDE RISK)

Risk to Life

Most of us have some difficulty grappling with the
concept of risk and deciding whether, or not, we are
prepared to accept it. However, without doing any sort
of analysis, or commissioning a report from an “expert”,
we all take risks every day. One of them is the risk of
being killed in an accident. This is worth thinking about,
because it tells us a lot about ourselves and can help to
put an assessed risk into a meaningful context. By
identifying activities that we either are, or are not,
prepared to engage in we can get some indication of
the maximum level of risk that we are prepared to take.
This knowledge can help us to decide whether we really
are able to accept a particular nsk, or to tolerate a
particular likelihood of loss, or damage. to our property
(Table 2).

In Table 3, data from NSW for the years 1928 to 2002,
and other sources, is presented. A risk of 1 in 100.000
means that, in any one year, 1 person is killed for every
100,000 people undertaking that particular activity. The
NSW data assumes that the whole population
undertakes the activity. That is, we are all at risk of
being killed in a fire, or of choking on our food, but it is
reasonable to assume that only people who go deep
sea fishing run a nsk of being killed while doing it

It can be seen that the risks of dying as a result of
falling, using a motor vehicle. or engaging in water-
related activities (including bathing) are all greater than
1:100,000 and yet few people actively avoid situations
where these risks are present. Some people are averse
to flying and yet it represents a lower risk than choking
to death on food. Importantly, the data also indicate
that, even when the risk of dying as a consequence of a
particular event is very small, it could still happen to any
one of us any day. If this were not so, no one would
ever be struck by lightning.

Most local councils and planning authorities that
stipulate a tolerable msk to property also stipulate a
tolerable risk to life. The AGS Practice Note Guideline
recommends that 1:100,000 is tolerable in newly

developed areas, where works can be carned out as
part of the development to limit nsk. The tolerable level
is raised to 1:10,000 in established areas, where
specific landslide hazards may have existed for many
years. The distinction is deliberate and intended to
prevent the concept of landslide risk management, for
its own sake, becoming an unreasonable financial
burden on existing communities. Acceptable risk is
usually taken to be one tenth of the tolerable risk
(1:1,000,000 for new developments and 1:100,000 for
established areas) and efforts should be made to attain
these where it is practicable and financially realistic to
do so.

TABLE 3: RISK TO LIFE

 

 

 

 

 

 

 

 

 

 

 

Risk (deaths per Activity/Event Leading to
participant per Death
year) (NSW data unless noted)
1:1,000 Deep sea fishing (UK)
110.000 | Motor_cycing. horse riding
. ultra-light fiying (Canada)
1-23,000 Motor vehicle use
1-30,000 Fall
1:70,000 Drowning
1:180,000 Fire/burn
1:660,000 Choking on food
1:1,000,000 Scheduled airlines (Canada)
1-2,300,000 Train travel
1:32,000,000 Lightning strike

 

 

 

 

More information relevant to your particular situation may be found In other AUSTRALIAN GEOGUIDES:

GeoGuide LR1 - Introduction
GeoGuide LR2 -Landsides
GeoGuide LR3 - Landsiides In Soll
GeoGuide LR4 = - Landsiides In Rock
GeoGuide LRS - Water & Drainage

GeoGuide LR5 - Retaining Walls

GeoGuide LR8  - Hillside Construction

GeoGuide LR9 - Effluent & Surface Water Disposal
GeoGulde LR10 - Coastal Landslides

GeoGuide LR11 - Record Keeping

 

The Australian GeoGuides (LR series) are a set of publications Intended for property owners; local councils; planning authorities;
developers; Insurers; lawyers and, in fact, anyone who lives with, or has an Interest in, a natural or engineered slope, a cutting. or an
excavation. They are intended to help you understand why slopes and retaining structures can be a hazard and what can be done with
appropriate professional advice and local council approval (If required) to remove. reduce, or minimise the risk they represent. The
GeoGuides Nave been prepared by the Australian Geomechanics Society, a specialist technical society within Engineers Austraila, the
national peak body for all engineering disciplines in Australla, whose members are professional geotechnical engineers and engineering

with a particular interest In ground engineering. The GeoGuides have Deen funded under the Ausirallan governments”

geologists
National Disaster Mitigation Program.

Australian Geomechanics Vol 42 No 1 March 2007 173