Vulnerability assessment of settlements to floods : a case study of Ward 7 and 9, in Lephalale Local Municipality, Limpopo Province South Africa

Abstract

Floods are one of the major natural hazards that occur with devastating effects globally. South Africa is one of the countries that is affected as flooding frequently occurs at different sub-national scales and with devastating impacts on human settlements. The variability of the nature, impact and frequency of flood occurrence in the country has heightened interest in the assessment and determination of flooding vulnerability, particularly in areas that have been affected or are likely to be affected in the near future. Given the uncertainties surrounding flood occurrence and the enormous damages resulting from the events, this study sought to assess the vulnerability of settlements to floods in Ward 7 and 9 of Lephalale Local Municipality. To accomplish this, both primary and secondary sources of data were used in this study. A mixture of closed-ended and open-ended household questionnaire, which was administered to 133 and 227 randomly selected households in Ward 7 and 9 respectively was used. In addition, a vulnerability index was developed using an indicator approach in order to determine levels of flood vulnerability in the study areas. Indicators were identified, grouped and normalised using the standardization method, then weighted using pairwise comparison method. The various indicators were then aggregated through a linear summation method into a vulnerability index. This index was subsequently used to produce a vulnerability map showing the spatial pattern of the different flood vulnerability levels in the studied areas. The results reveal that socioeconomic as well as physical factors influence settlements’ vulnerability to flooding disasters. Furthermore, the vulnerability index map showed that Ward 7 was more vulnerable to flooding, with an average index of about 0.16 while Ward 9 was less vulnerable, with an average flood vulnerability index of 0,07. The vulnerability map also indicated that out of the total land area of 13.54km2 occupied by settlements in Ward 7, 9.38 km2 was very vulnerable, 2.27km2 highly vulnerable and 1.89km2 had low vulnerability. In Ward 9, about 4.44km2 of settlements land was experiencing low vulnerability while 29.96km2 experienced very low levels of vulnerability. The study concludes that the high vulnerability of Ward 7 was a result of an interplay of factors that include its nearness to the stream, a high proportion of low-lying land, land use type and high population densities. The results of this study can serve as a basis for targeting prioritization efforts, emergency response measures, and policy interventions at the ward level for minimizing flood disaster vulnerability in municipal areas. The study recommends that flood vulnerability assessments should integrate socio-economic characteristics with physical factors in order to adequately assess vulnerability and therefore enable municipalities to anticipate floods and plan for them.