A GIS approach for flood vulnerability and adaptation analysis in Diepsloot, Johannesburg

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dc.contributor.advisor Annegarn, H.J., Prof. en_US
dc.contributor.advisor Flood control
dc.contributor.author Ngie, Adeline
dc.date.accessioned 2012-11-05T14:37:14Z
dc.date.available 2012-11-05T14:37:14Z
dc.date.issued 2012
dc.date.submitted 2012
dc.identifier.uri http://hdl.handle.net/10210/8095
dc.description M. Sc. (Environmental Management) en_US
dc.description.abstract The 2010/2011 floods saw the City of Johannesburg and many other municipalities in South Africa declared disaster ridden due to the number of deaths, homeless citizens and loss of property. Conventional Geographic Information System (GIS) approach is used to map flood vulnerable areas using floodlines while social surveys assess at-risk population through impacts of a hazard. This study then tests the hypothesis that combined approach to identify and map flood vulnerable areas is better than independent approaches, using Diepsloot township as a case study. Starting with aerial photographs as a base layer, ArcGIS 10™ was used to conduct spatial analysis of the flood-prone areas using the 1:50- and 1:100-year floodlines. The results mapped out dwellings vulnerable to flooding along the floodplains only. The survey probed the people’s perceptions, experiences and coping strategies with flooding. Findings from the field survey revealed some key observations, as follows:  The perception of 95% of respondents is that flooding is a major environmental challenge in Diepsloot township as confirmed by their experiences;  61% attributed this to construction of dwellings within floodplains; and  71% agreed that how strong a dwelling is in terms of construction materials also determines its vulnerability to flooding. In addition to floodplains, other sections of the settlement were identified through local knowledge as being vulnerable to various types of flooding - fast-flowing water, ponding and slope run-off. Dwellings on hill-slopes and besides storm water drains were identified as vulnerable to flooding. Slope measurements over the area were done using contours which corroborated these further areas of flood vulnerability as both low-lying and high slopes. Due to poor layout of dwellings, vulnerable units could not be counted but the extent was visible in the mapping. Long-term coping strategies and adaptation measures do seem to be in place, without interventions from municipal authorities. The combined approach for flood vulnerability assessment proved successful in creating a practical and affordable means to create a more comprehensive assessment, called for local knowledge engagement in policy development to mitigate flood disaster risk in the Gauteng City- Region. en_US
dc.language.iso en en_US
dc.subject Floods en_US
dc.subject Squatter settlements en_US
dc.subject Diepsloot (Gauteng, South Africa) en_US
dc.subject Geographic information systems en_US
dc.title A GIS approach for flood vulnerability and adaptation analysis in Diepsloot, Johannesburg en_US
dc.type Mini-Dissertation en_US

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