Lagos, the financial hub of Nigeria is the largest city of the country with the population of 17.5 million people. It lies in tropical climatic zone with significant rainfall throughout the year. The topography of the city is low-lying with slopes between 1-4% and elevations is just about 2m above sea level. 40% of the city’s area is covered by waterbodies and wetlands. The city is battling with climate change impacts. The intent of rapid urbanization and unplanned city growth has led to increase in frequent flood events. The low slope angle delays the drainage of rainwater.
More than half of the city’s population live in informal settlements. The high cost of housing and basic infrastructure lead people to live in low-lying areas. These are most vulnerable to floods in the city.
The existing drainage systems are in sufficient to prevent flooding. Existing dams are operating low. Illegal houses have constructed beside the designated area of canals which are obstruction to flow of storm water. Roads have been built without drainage system.
The Government of Lagos has initiated the project ‘The Great wall of Lagos’ or Eko Atlantic city which is 8.5 km long and12.5 wide intended to prevent the Victoria Island and adjacent areas from flooding and erosion. The city services include underground stormwater drainage system, a canal network and water treatment plants.
The existing city regulation requires to mandate minimum setback from water bodies and drainage channels to prevention loss from floods. The Lagos state government has introduced the Sustainable Urban Drainage systems to reduce the flooding in the city. The community participation is the helpful way to mitigate impact of floods. Community organizes sand filling of roads, building wooden bridges as walkways, clearing drainage channels for free flow of stormwater.