Fri, Aug 28, 2009 page8

• Managing disaster risks is feasible

  • By David Petley
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  For landslide scientists Taiwan has an almost mythical status, being one of the few places on Earth in which almost every conceivable type of landslide occurs on a frequent basis. The rare combination of high rates of uplift, weak rocks, steep slopes, frequent earthquakes and extreme rainfall events means that the landscape has an extraordinary natural susceptibility to landslides and debris flows. There is nowhere better to study these phenomena, and unsurprisingly landslide researchers have traveled from around the world to the central mountains of Taiwan.

  Personally, I feel privileged to have been able to work on landslides in Taiwan since 1991, and it is a country that I continue to visit on an annual basis at least. Of course the reasons why Taiwan is of such interest to landslide scientists are also the reasons why it can be such a challenging landscape in which to live. When the World Bank reported in 2005 on its “Disaster Hotspots” study it noted that: “Taiwan may be the place on Earth most vulnerable to natural hazards, with 73 percent of its land and population exposed to three or more hazards.”

  The last great disaster, the Chi-Chi [921] Earthquake, which happened almost exactly a decade ago, was a wake-up call to the hazards that mountain communities in particular face in Taiwan. It is undoubtedly true that a huge amount has been achieved in Taiwan to reduce disaster risk since this event, but the Typhoon Morakot disaster shows that there is so much more to do.

  Inevitably, and understandably, there is now a great deal of concern in Taiwan about the viability of its mountain communities in particular. As with many other mountains areas around the Pacific Rim the issues facing these communities are complex — many mountain villages are inhabited by some of the least affluent people in society, but these are people with long established links to the landscape who are often passionate in their desire to remain in their rural communities. Simple measures to relocate these people away from the mountains are rarely viable or successful from the perspective of the people involved.

  An alternative approach has been widely adopted in Japan, which has been to undertake engineering works on a massive scale to render the landscape less dangerous. However, such works are extremely expensive and are hugely damaging to the environment. In the mountains of Taiwan it is likely that such measures will have limited success, and the landscape will have been irreparably damaged.

  Unfortunately, in Taiwan much of the recent development in mountain areas, even in national parks and scenic areas, has been undertaken without fully considering the ways in which humans and natural processes interact in this type of environment. In many cases this is quite understandable — the processes that operate in the landscapes of Taiwan are so dynamic that our understanding of them is remarkably poor, especially during large typhoons — but the consequences are tragic.

  The race to build mountain hotels is perhaps the most obvious case, as Morakot so clearly showed, but there are many other examples. As roads, hydroelectric schemes, fruit farms, recreation areas and many other developments cause extensive environmental degradation, the landscape is responding with increased rates of erosion, mainly in the form of landslides, debris flows and floods, that put the population, buildings and infrastructure at unacceptable levels of risk.

  I do not believe that the way ahead is for a ban on construction in the mountains in Taiwan, and nor am I advocating that mountain communities are relocated onto the plains. I continue to believe that development in the mountains, including the construction of roads, hydroelectric power schemes and tourist facilities, is viable so long as the work is undertaken with great care.

  I also believe that it is possible for people to live, relax and work in the mountains with acceptable levels of risk, although as Morakot showed some of the existing communities and tourist facilities are built on highly dangerous sites. However, I do also think that some existing activities in the mountains cause too much environmental damage — in highland areas fruit farming appears to be causing high levels of degradation for example, and the construction of “hot spring resorts” is often insensitive and poorly planned. So here is my suggested manifesto for reducing the risk from landslides and debris flows in Taiwan:

  One, there is an urgent need to constitute a full national disaster management agency, with representation at the highest levels in government, to coordinate both disaster risk reduction and disaster response. The establishment in the US of the Federal Emergency Management Agency in 1979 has done much to reduce disaster risk there, although the events during and in the immediate aftermath of Hurricane Katrina in 2005 has served to emphasize the importance of risk reduction efforts as well as preparing for disaster events themselves.

  Two, Taiwan should develop and implement a comprehensive national plan for managing slopes, covering hazard and risk assessment, design standards for slope engineering, training and preparedness for both slope managers and for people living in affected areas; land use planning; research; monitoring of dangerous sites; and emergency response. This could effectively mirror the very successful slope management programs developed in Hong Kong and, more recently, in Malaysia.

  Three, there is a need to develop a comprehensive and well-resourced research program to understand the natural processes occurring in the mountain areas of Taiwan. The aim of the program would be to start to build a proper understanding of the processes that create hazards, especially during typhoons.

  The national environmental monitoring center proposed by National Taiwan University would be a sensible core element of this that could provide world class science outputs. The monitoring network could follow the hugely successful model of the GEONET program in New Zealand, which collects information on earthquakes, volcanoes and landslides there, providing both world class research data and an increased level of public understanding of science. There is a need to ensure that the outcomes of the research are fed back into the planning and management process, which is not always simple, but when done well it can be highly effective in reducing disaster risk.

  Four, there is a need to undertake a properly coordinated and sensitive program to evaluate the safety of all upland communities. Where risk is found to be high, the ethos should be to identify the best mechanism to bring this to an acceptable level without destroying the environment, usually through a combination of well-designed, environmentally sensitive engineering works, education programs and warning systems.

  In extreme cases relocation to nearby safe sites may be required. This program would need to be accompanied by work to determine the level of tolerable risk in this environment, and to ensure that there is a general understanding that the aim is not to eliminate risk, but rather to manage it.

  Templates for all of the above measures exist in other countries, and in each case the approach has worked. To achieve similar success in Taiwan will take considerable political will and of course some time. While the costs will be far from insignificant, they will be low in comparison with those associated with disasters such as Morakot.

  Hong Kong provides a real illustration of the effectiveness of such programs. In the 1970s, Hong Kong suffered a series of terrible landslide disasters, for example the 138 people killed in two landslide disasters in 1972. In response, the governor of Hong Kong established a government-level organization to manage and control slope development. The results have been highly impressive, with just three landslide fatalities in Hong Kong in the last decade.

  To achieve the same in Taiwan will require both political will and considerable investment, but there is little doubt that the management of disaster risk can be achieved.

  David Petley is Wilson Professor at the University of Durham in the UK. His research speciality is landslides.
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