Vulnerability analysis of building structures to floods The case of flooding informal settlements in Dar es salaam, Tanzania

Purpose There is evidence of increasing urban floods being aftermath of climate change. The purpose of this paper is to present findings-related analysis of vulnerability of building structures in informal settlements to floods and associated coping strategies. Design/methodology/approach The study adopted a case study strategy, supported by field surveys and laboratory experiments. The informal settlement taken as case study is Sunna sub-ward. Field surveys involved interviews, questionnaires and observations and tests were conducted to determine the strength of walls, blocks and mortar. Findings The findings reveal that vulnerability of building structures to floods are due to poor quality of materials used in construction of houses which are influenced by income levels, location (lower areas of Sunna sub-ward) and inadequate storm water drainage system. Moreover, socio-economic vulnerabilities do exist in the settlements and are related to lack of peace of mind, outbreak of disease and expenses related to repairing of flood affected houses. Coping strategies used in the sub-ward for built structures are building barrier walls at the front door of the house and use multiple strategies which are supported by reactive and recovery strategies. Research limitations/implications - The findings of this study were mostly affected by limited knowledge of respondents on construction materials and processes. Practical implications - Findings of the paper provide an insight on the effects of climate change on building structures in informal settlements and coping strategies in place to protect buildings. The outputs can be used for any other informal settlement in Dar es Salaam the only limitation is the terrain. Originality/value The paper recommends use of quality building materials and technicians/artisans, improvement of surface water drainage and training of residents on the effects of climate change and variability. In addition, promising coping strategies should be adopted while those under-performing should be discouraged as they increase the cost burden among the urban poor.