Using geographic information system to evaluate land use and land cover affected by flooding in Adamawa State Nigeria

摘要

The impact of natural disaster on land use and/or land cover (LULC) has emerged as a global phenomenon and is perhaps the most significant regional anthropogenic and natural disturbance to the environment. Natural disasters and land use change are major concerns all over the world, and if these two concerns exist together along large rivers, then the consequences for people and the human activities may be severe. This study evaluated land use and land cover affected by flooding along Benue River in Adamawa State, Nigeria. Satellite imageries of land use, vegetation, settlements and drainage basins were collected from the National Space Research and Development Agency, Abuja, and the National Centre for Remote Sensing, Jos. The imageries were collected for the selected study period: 2002, 2012 and 2014, all between October and November. The three imageries were used to generate a LULC map of the study areas. Land cover and/or land use and flood inundation analysis was carried out using Integrated Land and Water Information System image processing and Earth Resources Data Analysis (ERDAS 9.2) image processing geographic information system software. A supervised classification was done using the LULC samples collected on the field. This final product generated a LULC map for the entire study area. Six LULC classes were generated: waterbodies, farmland, vegetation, settlement, alluvial deposits and bareland. The study revealed that in 2002 floods affected 38% farmland and 53% vegetation of the total inundated areas. In 2012, it affected 56% farmland cover and 35% vegetation, while in 2014, it affected 51% farmland cover and 42% vegetation cover of the total inundated area of Adamawa State. This study concluded that the most flood-affected land cover is farmland and recommended that farming activities should be located outside flood-prone areas in order to avoid food insecurity issues during and after flood disaster in the state.