Application of geospatial techniques in mapping urban flooding in parts of Victoria island

This study aimed at application of geospatial techniques in mapping of urban flooding in parts of Victoria Island. Its objectives were to delineate different risk levels of flooding in the study area, to determine the effect or impact of flooding on different land cover types and to produce flood risk map of the study area. The methodology involves data acquisition, data processing and reclassification and overlay analysis. This study has been able display the usefulness of Remote sensing and GIS technologies in classifying and in identifying areas with high, moderate, low risk of flooding within the study area. The classification achieved an overall Classification Accuracy of 84.99% and kappa statistics of 0.8792. The image classification results indicate that built up area accounted for the largest land cover/use of about 50.41% with an area of 856hectares while water body had the second largest with 23.32% and an area of 396 hectares, open space had 14.72% with an area of 250 hectares and vegetation had 11.54% with an area of 196hectares. The flood risk mapping results also that high-risk zone occupied 34.68% of the entire study area, covering an area of 589 hectares, while moderate risk zone occupied 47.05%, covered an area of 799 hectares. low risk zone occupied 18.25% covering 310 hectares. It was recommended that the results achieved in this research should be used as a base to help identify areas at risk of being flooded in the study area