Monitoring Land Use and Land Cover Change in the Nandoni Dam Basin, South Africa

Abstract

Land use activities and land cover (LULC) changes have been widely acknowledged as the main drivers of environmental change at all spatial-temporal scales in some South African dam basins. The consequence of these land use activities causes encroachments, land cover changes, sediment deposits, deforestation, and severe flood damage, which reduces water storage capacity in dam basins. The challenges of land use activities have highlighted the need to monitor LULC changes in the Nandoni Dam basin. Most of South Africa's dam basins must meet the water and socio-economic needs of local communities. However, these dam basins are located in remote, inaccessible terrain, making it challenging to monitor land use activities and encroachments in a timely manner. This research aims to apply remote sensing and GIS methods to monitor LULC change patterns by using remote sensing images and GIS data to quantify the spatio-temporal LULC change patterns in the Nandoni Dam basin. This study investigated the Nandoni Dam basin’s LULC changes using Landsat TM 1997, 2005, and ETM+ 2021 images. The six LULC classes classified are water bodies, forests, floodplains, built-up land, bare land, and agricultural land. The images were successfully delineated using GIS zoning boundary data and then classified through a supervised maximum likelihood classifier. The results of the classified images showed significant changes in all classes, with built-up land being the major encroachment into the dam basin, covering 18.28% in 1997, 21.46% in 2005, and 19.12% in 2021. These findings provide considerable spatio-temporal information on factors causing LULC change patterns and how to improve the understanding of the amount and rate of encroachment of the dam basin.