Aquatic informal settlements: Vernacular design strategies for flood-resilient built environments

More frequent extreme weather events caused by climate change increase the risk of flooding in informal settlements, exacerbating vulnerabilities stemming from inadequate storm water management infrastructure, dependence on on-site sanitation, and precarious settlement sites. Addressing these challenges requires climate change adaptation of informal settlements. This study focuses on adaptation of the built environment to enhance flood resilience among communities with long-standing traditions of settlement in aquatic settings. It employs qualitative visual analysis of satellite imagery covering aquatic informal settlements to document urban level design strategies along with photographic field data from Lagos, Nigeria, and Châu Đốc, Vietnam to document building level design strategies. The analysis identifies several key vernacular flood resilience design strategies developed without involvement of architects, planners, and engineers, including the construction of artificial islands that consolidate settlements at the block level and spatially separate flooded public areas from elevated, fortified private zones protected from flooding; the use of raised pedestrian pathways to separate mobility systems from flooded areas; and the incorporation of prefabricated concrete stilt elements in housing construction to protect domestic environments from flooding at low cost. The study discusses the potential of these vernacular design strategies to inform climate change adaptation in flood-prone informal settlements.