The impact of a landslideProfessor Malcolm Anderson, from the University of Bristol, has spent more than 20 years studying how to predict and reduce the risk of landslide disasters around the world. The full impact of landslides is often underestimated because they are often the result of large-scale triggering events such as hurricanes and tropical storms.

Globally, more and more people are moving to urban areas and in developing countries often only the steep slopes around cities are available for the poor to build their homes on. They create densely populated shanty towns on the hillsides with no formal infrastructure and with the constant risk of landslides. Typically, in the Eastern Caribbean, more than 60% of the housing is of this nature. To these nations, landslides can have a huge economic impact: it can cost as much as US$15m to relocate, rebuild and re-house just one community after a disaster, let alone the human costs resulting from these devastating events.

How are the risks measured?

Professor Anderson wrote a piece of software called CHASM (Combined Hydrology and Stability Model) which models the dynamic effect of rainfall and several other factors on the stability of slopes. Using CHASM can help engineers to predict potentially devastating landslides and assess different ways of reducing risk.

Six years ago the opportunity arose for Professor Anderson to apply this research in a way that would help people living in developing countries. Professor Anderson recalls “We needed to demonstrate to policy makers in developing countries that water management was crucial in limiting landslide risk within these settlements, and cost effective solutions could be found, without uprooting or disrupting existing communities”. 

He continues: “The usual response to landslide risk is for people to build small retaining walls, usually at a high cost to themselves, but rarely can they be substantial enough to control earth movement. Water management is the answer to this – retaining walls can’t do it.  We had the solution, but needed to prove it.”

By working with communities and local engineers, he and his research associate, Dr Liz Holcombe, gathered the local data needed to understand the causes of the landslides.  The effects of vegetation, density of housing, surface water and soil conditions were modelled using CHASM. This confirmed Professor Anderson’s assertion that the key to reducing the risk was better surface water management and drainage.  The Government of St Lucia endorsed this new approach and the MoSSaiC (Management for Slope Stability in Communities) project began.

Promoting and funding “MoSSaiC”:

Professor Anderson’s vision was to show government policy makers directly and help communities through using the MoSSaiC methodology in the field. But generating funding support based on an untested idea was extremely difficult. So he and Dr Holcombe paid for the first few trips to the East Caribbean themselves.

“We chose St Lucia as our lab.  There is a high risk of hurricanes and landslides, and all the major international aid donors are there so they could see the science being tested on the ground.” Professor Anderson says “We simply got on a plane and started working out there.”

Dr Holcombe travelled with him to St Lucia to collect field data for her PHD research. This also involved talking to government officials about landslide risk reduction approaches and policies. Once there, they could see immediately that they could reduce risk through providing drainage to communities.

“The government were building footpaths in Skate Town at that time, and we advised where drains could also go.”  Liz explains. “We showed the community what caused the landslides, and worked with them to produce ‘Hazard Maps’. These can’t be done without local knowledge of the area and they indicate where the drains should go to remove surface water”.

The government found the money for the drainage to be built and used local labour, creating employment and opportunities for the people to gain new skills in the process.  The scheme proved to be successful even after heavy rains, with no landslides occurring, so the St. Lucia government budgeted for a further 6 communities to be helped the following year. This was an important signal, and other funding streams followed, including support from the World Bank, USAID (US Agency for International Development) and UNDP (United Nations Development Programme).  What started out from the pockets of two academics had evolved into a global partnership over a five year period, and MosSSaiC methodology is now being rolled out more widely, to countries such as St Vincent and the Grenadines, Dominica, Jamaica and potentially areas of Latin America.  To date MoSSaiC has helped 12 communities and approximately 3,500 of the poorest people living in unplanned settlements.

One of the most important aspects in the process is that of community engagement. Local people are involved throughout: they help with mapping and planning; they tender for the construction work; they can learn new skills through building the drainage and of course they benefit from fewer landslides as a result.  Dr Holcombe is also pleased to report that:

“People don’t get water in their homes any more and they can sleep at night now without the fear of a landslide when it’s raining. Their health is also better because of the absence of standing water, reducing the number of disease-carrying mosquitoes”.

The role of SETsquared:

SETsquared provided a £12,000 grant to the project in its 2nd year, through its Social Enterprise Fund, and offered consultancy support as part of the package. This included help with business models; how to work with NGO’s; gaining recognition and influencing government policy makers, in particular identifying ways to illustrate the financial benefits.

It is estimated that risk reduction programmes such as MoSSaiC offer savings of $2-3 to every $1 spent. Utilising the local community also means that about 80% of the funding Professor Anderson obtains is actually spent in the community. This is recognised in the region and beyond to be truly cost-effective.

What’s next for MoSSaiC?

The technicians and engineers within developing countries such as St Lucia are being trained to be able to use the CHASM software themselves to understand and reduce the risk of landslides. The software is evolving all the time through the Professor’s PhD students, and the recent involvement of the “Random Hacks of Kindness” project* which has been helping to make the software more accessible.

Although Professor Anderson and Dr Holcombe have been able to help many people in extremely difficult living conditions, their last comment on working with the communities in the eastern Caribbean is a humbling one:

“You learn more from them than they learn from you. These people are very vulnerable – but the first thing they ask for is work – we learn so much from their motivation to work with us.”