Land use/cover change and its implication for flood events in Benue State, Nigeria

Abstract

The aim of the study is to analyse the implication of land cover change on flood events in Benue state, Nigeria over the period 1990-2020. Landsat TM (1990); Landsat ETM+ (2000, 2010); and Operational Land Imager (OLI) (2020) were used. The Landsat imagery dataset was sourced from the Earthexplorer platform from United States Geological Surveys (USGS). Changes in land cover were measured using time series of remotely sensed data (Landsat TM, ETM and OLI). This study adopted the Error Matrix approach in ArcGIS to assess the accuracy of the classification. From the analysis, it was observed that, there is a significant decrease in forest land cover with annual decrease 3.26% within the 30 years (1990 to 2020) while cropland and pasture land increased with annual rate of increase of 2.21%, built up area 2.13% Water 0.04%, bareland/sandbar with 11.51% annual rate of change. These land cover dynamics is capable of creating environment suitable for increased surface run off and subsequently flooding. This situation coupled with significant increase in rainfall trend (positive constant of 5.45), will mean increase in flood events (positive constant of 8.72) and vulnerability of people, settlement especially urban and human activities within flood prone areas in Benue state. The relationship between land cover change and flood events shows that there is significant influence of change in forestland cover, cropland/pasture, built up area, water body and bare surfaces on flood events in the area. This implies that changes in land cover is contributing significantly to flood generating mechanism which means that all things being equal, flood events in the area will continue to increase in terms of frequency, magnitude and its impacts on the area.