Assessment of Land Use Changes and Impacts of Dam Construction on the Mbaa River, Ikeduru, Nigeria

This research was conducted in order to ascertain the impact of the earth dam on the physical environment of Mbaa River using Geographic Information System (GIS) and Remote Sensing (RS) techniques. The Specific objective was to use multi-temporal images to assess land use and land cover changes as well as determine the extent of land degradation around the watershed as a result of the dam. Landsat 7 ETM+ of 2000 of path 188 and row 56, and the Nigeria Sat-X image of 2nd December 2011 were classified to identify the changes in the physical features of the watershed. The study revealed variations in the land cover of the study area with land degradation and erosion in both the upstream and downstream area and submergence of farm lands in the upstream. The result from the watershed delineation revealed that the shorelines of the upstream increased to an approximate length of 109 m while the downstream shrank to 18 m. There was about 8.05% reduction between the years 2000-2011 in the total area covered by the water body in the area. Urgent action need to be taken to reclaim degraded land especially downstream of the dam through re-afforestation.