The year 1987 holds painful significance for the Andean valley city of Medellín. On 27 September, heavy rainfall caused a catastrophic landslide on the east side of the valley, claiming more than 500 lives. The tragedy was a stand-out example of the dozens of landslides that have resulted in the deaths of an estimated 784 Medellín citizens in the last 80 years, and which continue to endanger the city’s increasing number of informal communities. As many as 44,600 households are estimated to be at risk within the city’s metropolitan area.
An early warning system that can sense weather changes already exists. However, it is monitoring the ground and water that concerns researchers from Heriot-Watt, Colombia and Edinburgh universities. They hope WhatsApp might be the answer. A pilot project in the community of Pinares de Oriente – just a few hundred metres from the site of the 1987 landslide – has trained community members to recognise and photograph early signs of danger and add them to a WhatsApp group. The signs include ‘changes in inclination in trees and vertical posts, changes in vegetation or slow movement of soil cover over time,’ says Harry Smith, leader of the Heriot-Watt team.
Why WhatsApp? First, it records the time and date automatically, which allows the photographs to be linked to heavy rainfall events. Second, there’s the app’s ubiquitousness. ‘People in the low-income communities we are working in are already very familiar with it and use it socially,’ says Smith.
It is hoped the idea will enable more communities to participate in monitoring landslide risks. Most of the at-risk areas are informal communities, where there is a level of distrust of the local authorities. ‘They feared eviction from the city council if they spoke up about the risks,’ says Gabriela Medero, associate professor of geotechnical engineering at Heriot-Watt. She hopes that the method can be used in larger communities harbouring similar fears, where incidents are going unreported, saying: ‘We are upscaling the community-based monitoring system in two other informal settlements in Medellín, Colombia, as well as in a favela in São Paulo, Brazil.’
This was published in the August 2018 edition of Geographical magazine
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