Analysis of vulnerable urban properties within river Ala floodplain in Akure, Southwestern Nigeria

Abstract

Flooding is a serious problem affecting the urban environment and threatens the lives and properties of the urban settlers, including Akure, Ondo State in Southwestern Nigeria where it has become recurrent. The study assessed the impact of flooding on some elements at risk along Ala River in Akure, Ondo State, Nigeria using Remote Sensing and GIS techniques. The land use/land cover change detection of Ala River catchments was carried out using 1984, 2000 and 2015 Landsat images. Each of the classes and the positional accuracy of the river were validated using GPS (Garmin78SC). Buffers were generated around the river channels using high resolution Google Images as input data. The result of LULC showed that there was positive increase in built up land use from 17.65% in 1984 to 24.96% in 2000 and 65.67% in 2015. The results of buffering analysis showed that 105, 214 and 554 buildings with the estimated population of 2520, 5136 and 13,296, fall within 10 m, 20 m and 30 m distance to the river. The study concluded that the incessant occurrence of flood in the study area was as a result of some driving forces such as climate, rapid urbanization, terrain configuration and violation of building regulations that rendered most properties along the flood plain very risky.