Flood Vulnerability Assessment Using Geoinformatics Techniques: A Case Study of PortHarcourt, Nigeria
ISBN 978-85-88783-11-9
Authors
1Onosemuode, C.
1FEDERAL UNIVERSITY OF PETROLEUM RESOURCES Email: krisonos@yahoo.com
Abstract
Abstract The application of Geoinformatics in flood vulnerability assessment in PortHarcourt was carried out to determine the extent the flood impacted roads and buildings. The dataset used for the study include Ikonos imagery of 5m resolution, street map of the study area and google earth map of 2014. The entities created for the analysis include that for buildings, roads and rivers. In the manipulation of data, buffer analysis was carried out at buffer distances of 10m, 20m, 30m and 50m to determine the effect of the flood on buildings while a buffer distance of 60m, 80m and 100m was carried out to determine the effect of the flood on the roads in the study area. The weighing criteria adopted was the subjective approach that generated a class range of 0-20m,21-30m, 31-40m, 41-50m representing vulnerability rate of high, moderately high, moderate and low respectively for buildings while the class range generated for roads are 0-40m, 41-80m, 81-120m respectively representing very high, high and low respectively. The data base was subjected to query analysis and the result shows that 32 buildings were within the very high vulnerability rating, 84, 146, 204 buildings were within the high, moderate and low vulnerability rating respectively. The result of query for roads showed that no road was within the very high vulnerability rating while 6 roads and 22 roads were within the high and low vulnerability rating respectively. The highly impacted roads in the study area disrupted economic activities as most commercial activities that those roads serve were inaccessible for a long period resulting in dislocation and the dysfunction of normal life for a period much beyond the duration of the flooding.
Keywords
Flooding; Vulnerability; Geoinformatics