Risk Assessment Analysis of Accelerated Gully Erosion in Ikpoba Okha Local Government Area of Edo State, Nigeria

The problem of accelerated erosion has been on in Ikpoba-Okha Local Government Area (LGA) in particular and Nigeria at large for some decades now and all past attempts at solving the problem have proved ineffective and thus constituting risk to the people living around the gullies in the area. Therefore, this study aimed at determining sediment loss from the gully sites, the vulnerable areas and threat posed by impact of gullies in the study LGA. Oregbeni Housing Estate and Ede School gully erosion sites in the Ikpoba-Okha LGA were purposively selected for this study. Primary data were collected using GPS receiver.These include the geographic coordinates and elevation of the study gullies catchments which were integrated with the secondary data obtained from satellite image, topographic, geologic, road and lay out maps of the area using Arc GIS 9.3 software. The results of the satellite image classification analysis showed that accelerated gully erosion accounted for 2% (100466.57 m2) of the total areal extent of the study LGA (5189010.57 m2). Of this 2%, Queen Ede School gully accounted for 96957.13 m2. The total estimated sediment loss from Queen Ede School and Oregbeni Housing Estate gullies were 359,173.22 and 48,212.62 tonnes, respectively. These indicated severe land degradation in the study area.