Demolishing Lagos informal settlements destroys the city's own flood defences, research finds
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Research across 20 informal settlements in Lagos finds residents build the drainage, raised walkways and water systems the city depends on, and that clearing settlements in the name of climate protection leaves people more exposed to flooding.
Lagos authorities have demolished at least six settlements since July 2023, and each clearance removes working flood-management infrastructure along with the housing, according to research by climate social scientist Brianna Castro on adaptation infrastructures in 20 informal settlements in the city.
In a city where more than 40 percent of the surface is water or wetland and climate change is increasing flooding, sand dredged from the lagoon and sold to households and building sites is itself a flood defence: it is packed around foundations and under floors to lift land and structures above water, including in neighbourhoods far wealthier than those where it is collected.
The research documents the systems residents have built themselves. In the Ijora settlement, plank bridges on bamboo supports have grown from temporary rainy-season walkways into a permanent raised network, rebuilt higher each time the water gains on them. Houses use doorway barriers and interior floors raised with compacted plastic waste, with the height set by high-water marks from past floods. Residents also dig boreholes and sell water to surrounding neighbourhoods, and work as sand divers, waste collectors and water sellers.
Lagos has grown from about a million people in 1970 to somewhere between 17 million and 21 million, and more than 60 percent of residents live in informal housing, while the state government pursues a vision a housing commissioner described to the researcher in 2016 as building "the next Dubai". That ambition is visible in Eko Atlantic, a district rising on land reclaimed from the ocean behind a seawall that protects high-end real estate, while researchers have documented worsened erosion and flooding in communities left outside it.
The consequences of clearance were visible in Otodo Gbame, a waterfront fishing community of tens of thousands demolished in 2016. The bridges went, along with shared wells and informal electrical connections, and sand divers, fish smokers and water sellers lost the shoreline and the customers their work required in the same week. Residents scattered across Lagos were cut off from the materials and neighbours that made their adaptations function.
In December 2025 bulldozers arrived in Makoko, Nigeria's largest informal settlement, and the United Nations said more than 40,000 people had been displaced. Lagos State suspended the demolitions and announced a US$10 million plan to build a "water city" in Makoko's place, and the research argues that recording the settlement's existing water networks, waste routes and raised walkways before that design is finalised could be the difference between a project that works and one that destroys flood-management capacity.