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Saint Lucia: From Landslides to Stability

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Saint Lucia: From Landslides to Stability


The development community has been working with countries around the world for decades to increase investments in disaster risk mitigation. For a long time, the benefits of these investments were expected, but not yet demonstrated. This is no longer the case. One of the success stories of persuasive results of smart mitigation investments is a “mosaic” of a few simple elements put together on a few Caribbean islands, including Saint Lucia.




On this island, as on many other Caribbean islands, frequent heavy rains, mountainous topography, and volcanic geology combine to create high-hazard conditions for landslides. On some slopes, landslides are common even when rainfall is only mild. For communities living on such slopes, this creates conditions of perpetual uncertainty and frequent losses from landslide damage.

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In 2004, an academic team from the University of Bristol came up with a way to address this problem: Management of Slope Stability in Communities (MoSSaiC). Its work started in a number of communities with the support of the Government of Saint Lucia, and later continued in partnership with several international organizations, and particularly the World Bank, through the Saint Lucia Second Disaster Management Project. The approach centers its vision on sustainable foundations for community-based landslide risk reduction, rooted in science, communities, and evidence.

The scientific foundations of MoSSaiC focus on the identification of localized physical causes of landslide risk (such as poor drainage), the identification of appropriate mitigation measures to address these causes (such as constructing drains), the justification of these solutions to both the community and the government, and the explanation of the need for a certain standard and quality of design and construction, so that the root cause of the hazard is effectively addressed.



What sets MoSSaiC apart from many other interventions is that it is rooted in communities from start to finish. Community residents are engaged in identifying landslide risk causes and solutions, employed in constructing the drainage solutions, and they work together with government managers and practitioners to deliver the mitigation measures. As a result, the vision for this proactive, sustainable approach to slope management is shared, championed, and owned by the communities themselves, not only by the government or an implementing agency.

The evidence-based piece of MoSSaiC continues to grow over time. The majority of project funding and time is spent directly in the communities, and due to the high levels of local engagement, both behavior and policy are gradually changed. Now that MoSSaiC has been implemented in a dozen communities, we can also safely say that the investments of resources and effort have definitely paid off: In October 2010, Hurricane Tomas (a 1-in-500-year 24-hour rainfall event) caused numerous landslides all across Saint Lucia. However, none of the vulnerable communities with MoSSaiC interventions experienced any landslides at all, despite the fact that they frequently used to be affected by substantially weaker events in the past. To date, 261 homes have benefitted from the Second Disaster Management Project MoSSaiC interventions.

According to a detailed economic analysis undertaken in 2010, MoSSaiC has been shown to have a cost/benefit ratio of 1:2.7 in a sample community in Saint Lucia (Holcombe et al., in press1). These numbers provide a strong incentive for other developing countries in the region and beyond to follow Saint Lucia’s example.


Bank Collaboration

Close collaboration has been established since 2009 between MoSSaiC and the Latin America and the Caribbean Disaster Risk Management team of the World Bank. The results of this collaboration have been gathering considerable momentum. They were mentioned in the World Development Report 2010 and will be profiled at the upcoming Aid Effectiveness Showcase to be hosted at the World Bank this fall. Last year, they also won the grand prize at the Washington, DC Random Hacks of Kindness (RHoK) hackathon, where the academic part of the MoSSaiC team partnered with programmers to significantly simplify the user interface of the landslide risk simulation software used in preparing specific interventions.


Toward the Future

To make MoSSaiC more readily accessible to more communities with high vulnerability to landslides, MoSSaiC and the Latin American and the Caribbean disaster risk management team  are currently preparing a book (Managing disasters in small steps: Community-based landslide risk reduction), to be followed by an ePractice web-based toolkit of resources for country practitioners and communities.

For specific information about MoSSaiC, contact Niels Holm-Nielsen (, Senior Disaster Risk Management Specialist of the Latin America and the Caribbean DRM Team.

1 Holcombe, E.A., Smith, S., Wright, E., Anderson, M.G. (in press) An integrated approach for evaluating the effectiveness of landslide hazard reduction in vulnerable communities in the Caribbean. Natural Hazards. DOI: 10.1007/s11069-011-9920-7.



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