Afgooye District Suitable Potential Higher Grounds For Evacuation During Flooding

Datasets used for the analysis are :- Flood Extent, Elevation, Slope, Topographic Wetness Index (TWI),Drainage Density, Strategic Boreholes, Settlements, Land Cover and Roads\r\nBased on a predefined criteria, each of these datasets were first clipped to areas outside the flood extent but within a maximum distance of 10 Km from the flood extent boundary. The outputs were then reclassified into two classes namely; Suitable and Not Suitable. Using an iterative approach, each of these datasets was used to assign a weight to the suitability of a site. These weights are indicated on table 2 below. Thereafter, a multi-criteria evaluation weighted overlay operation was undertaken to determine the potential areas for evacuation sites. An area was then computed for the potential sites and their distance from the flood extent established. The output was then post – processed to remove invalid geometries and each site was ranked based on the distance from the flood prone area. Sites that are closer in distance were deemed to be most suitable hence a higher rank. The final layer was then visually checked based on the density of the topographic Wetness Index (TWI) which is based on runoffs during floods. Areas with dense TWI were eliminated to remain with only continuous areas.