Resumen de Landuse, landcover change dynamics and flooding in the lower Niger basin Onitsha, South Eastern Nigeria
Ezebube M. Nkiruka, Ani D. Chinedu, Uchegbu N. Smart
This study looked at the factors contributing to Onitsha's incessant flooding, specifically landuse and land cover depletion. The landuse/landcover changes during a period of ten years (2008 – 2018) and the relevant variables were studied in the lower Niger Basin, focusing on Onitsha, Anambra State. Three sets of Enhanced Thematic Mapper Plus (ETM+) Landsat imagery maps from 2008, 2013, and 2018 were used to construct three Geographic Information Systems (GIS) based landuse/landcover maps of the research location and cross-tabulation method was adopted for the Change Detection analysis. The results demonstrated that between 2008 and 2013, built-up areas expanded by 9.4%, and between 2013 and 2018, they increased by 9.4%. Then it grew by 5.5%, resulting in a total area of 470 ha and 275 ha. Then, between 2008 and 2018, built-up added 745 ha in the study region, whereas vegetation lost 638 ha between 2008 and 2013, and another 97 ha between 2013 and 2018, for a total loss of 735 ha. Between 2008 and 2013, the area of bare ground increased by 1.3%, to 65 ha, while between 2013 and 2018, the area of bare ground decreased by 0.3%, to 15 ha. This study also discovered a 40-hectare rise in waterbody between 2008 and 2013 and a 100-hectare loss between 2013 and 2018. Based on the findings, the changes in landuse/landcover change detection provided insight into non-compliance with existing landuse acts and the implementation strategies of government agencies enforcing them.
