In his home on a steep hillside in the neighbourhood of Golondrinas in Medellín, Róbinson Velásquez Cartagena stands proudly next to two large tanks of water – a rainwater harvesting system he designed and built to help reduce the risk of flooding and landslides.
It is one of the nature-based solutions that Velásquez and others in the community have proposed as part of a disaster risk and climate crisis adaptation plan for Comuna 8, a growing informal settlement of 150,000 people in Colombia’s second-largest city.
As a result of inadequate engineering, neighbourhoods such as this, where brick houses with corrugated metal roofs are densely stacked on unstable ground, are susceptible to landslides and floods. In 1987, a devastating landslide killed 500 people in the area.
Organisations and residents such as Velásquez Cartagena came together and, in 2020, began to develop the Local Agreement for Inclusive Climate Action, in line with the Medellín city council’s Climate Action Plan.
After three years of debate and groundwork, the plan was formally launched in August 2023 by several organisations, including Medellín’s disaster risk management department (DAGRD), the housing and habitat committee for Comuna 8, and Heriot-Watt University in the UK.
Now a model for Medellín’s 4 million residents, the plan comprises eight measures to address climate risks, including managing rainwater, reforestation to control erosion and sedimentation on hillsides and in ravines, and establishing eco-gardens and agroforestry systems.
While the city aims to implement similar plans across all 21 comunas, challenges remain in securing government support and funding for grassroots initiatives.
“I started the rainwater harvesting system because I wanted to prove that it can reduce the risk of disasters by reducing the water that runs on to the streets, which can flood when it rains,” says Velásquez Cartagena, a community leader who is studying a master’s in environmental engineering at the University of Antioquia.
His system collects water from the rooftop drainage and stores it in containers; he then uses the water for his washing machine and toilet.
Originally a disaster-management scheme, the plan was expanded by the community to include climate adaptation. As well as the eight community measures, it outlines climate risks and vulnerabilities, a heat map, past floods and landslides, responsible stakeholders and action points.
“In the plan, there are nature-based solutions, with several that are not that expensive or hard to make,” says Velásquez Cartagena. “We need solutions like that because the level of risk is very high.”
In the El Pacifico neighbourhood, Nancy Elena Quiros Correa oversees a small 9 metre by 3 metre (30ft by 10ft) plot that was set up as a community tree nursery last year.
“The nursery will prevent rocks from falling, soak up water when it rains, and increase biodiversity,” she says.
Quiros Correa knows first-hand the impact of weather-related disasters. “Around 2011, rocks struck this wall [which was originally made of wood] twice, causing it to collapse,” she says, pointing to the yellow-painted wall in front of her home. She says the climate in Medellín is changing. “It used to be much cooler. Now we have high temperatures, but also more rain.”
She recalls a severe flood that happened nearby in 2020. “It affected many buildings and houses,” she says. “We want the tree nursery on the mountain so it can prevent that from happening again.”
Other projects include a rainwater-harvesting system installed at a local community centre last year and an ecological restoration garden.
“The garden will restore nature and stabilise the land,” says Harry Smith, a professor in global urbanism at Heriot-Watt University, who has worked with Comuna 8 on environmental projects for the past 10 years. “But it also stops one of the problems they have there, which is land invasion as people continue to build new homes on land that has been sold illegally by armed groups.”
While the plan was being approved, the community “hit the ground running”, says Smith. “They wanted to do some pilot projects to show that they don’t need to wait for the municipality to come along and do things.”
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Velásquez Cartagena is working with community leaders to produce a user-friendly guide to the plan, with engaging graphics, that can be printed and shared on social media.
With support from a strong community, the work in Comuna 8 has led to a disaster risk and climate adaptation plan for all 21 comunas in Medellín.
Juan David Moreno, the head of the technical team at DAGRD, says: “The work in Comuna 8 was a pilot, and we developed it for the rest of the communities.”
Yet, each one is different. “In some communities, you have different needs,” says Moreno. “We assessed the terrain, the community needs and the different hazards.”
A critical lesson was learned during the process, he says. “The main lesson from Comuna 8 was that we needed to work closely with the people, as they live in the territories and know the local hazards.”
He says another challenge is yet to come. “Every actor, including every department of the local government, as well as the community, needs to implement the proposals. This is the biggest challenge.”
Despite all of their work, Quiros Correa still has reservations about what the plan will achieve. “I now have a more realistic view of the local government actions. Everything that we have achieved here has involved fighting and negotiating with the local government.”
Velásquez Cartagena says he wants the plan to be promoted across the country and Latin America as a strong example of communities and organisations working together to create effective climate adaptation.
“The plan reflects the views of the community and the organisations’ proposals that we have made for years,” he says. “We want the municipality to acknowledge it financially. We hope they put effort into implementing it, as these small actions make a real difference.”
