Analysis of Patterns of Encroachment on Flood Vulnerable Areas by Settlements around River Kaduna, Kaduna South LGA, Nigeria

Abstract

This study assessed the patterns of encroachment of settlements on flood vulnerable areas of river Kaduna. The ENVI version 4.7 software aided the import of images one after the other in a Geo-tiff format. Proximity analysis was then applied to discover relationships. The river Kaduna was buffered using the multi-ring method and various settlements were overlaid on the buffer ring to determine settlements at risk. Change computation was made between 1990 and 2010 with the ENVI.4.7 version basic tools. Since image is classified, the detection statistic was used where the equivalent classes were defined and the needed pair was added. This provided the change detection statisticoutput. Results show the rate of change of the flood vulnerability and other land use/land cover classes of the study area. Also, since settlements can be observed within the very high risk zones to the left or right of the river, this suggests that the area has a very high risk of flood as corroborated by the GIS results. In events of flooding, the blue zone may be used as a staging area for rescue operations within the area.

Keywords: Flooding, floodplains, remote sensing, GIS, river Kaduna.