This summary reviews evidence on the urban flooding impact, risk factors, and management and mitigation measures in Lagos and other cities in Nigeria. Flooding is a common problem every year in many cities across Nigeria, but the impacts of flooding are poorly documented. There is no consistent set of statistics at a national or sub-national level that can be used to compare the impacts of flooding across cities, and reports that focus on particular flood events are often incomplete.
The literature notes the principal factors contributing to flood risk including uncontrolled urban growth, inadequate and poorly-maintained drainage systems, solid waste management practices, weakness in institutional capacity and coordination, and warning systems and public awareness. The evidence base for flood impacts, risks, and mitigation efforts at the city level in Nigeria is limited, and much of the information available is low quality, inconsistent, or outdated. Many rely on surveys of city residents rather than objective empirical data, and some of these surveys appear to be poorly designed. A significant number of the academic publications available have been published in non-mainstream journals without the usual level of academic peer review. Recent information is scarce, and a significant amount of the available evidence dates from 2011 and 2012, which coincides with an episode of nationwide flooding that was among the worst in Nigeria’s history.