Geospatial Assessment of Land Use and Land Cover Patterns in the Black Volta Basin, Ghana

摘要

The Black Volta Basin in Ghana has experienced some losses in its productive lands due to mining. This study assessed the Land use/cover (LULC) changes within the Basin for a period of eighteen years, and mapped current and potential mining hotspots in the Basin. The study used multispectral Landsat images for the years 2000, 2015 and 2018. Supervised classification method and Spectral Angle Mapper were used to classify and map the LULC types. Feature-based extraction method was then used to delineate mining sites along the River in the Basin. Six (6) LULC types were classified. Findings from the study revealed that four of the classified LULC experienced some form of decline between the years 2000 and 2018, except Bareland and settlements which consistently increased within the period, with Barelands recording the highest increase of 21% between 2000 and 2015 and 18% between 2015 and 2018, signaling a sharp increase in the three year period. From the feature-based extraction, 312 segments of an average area of 8.4 km2 of each segment were found to be mining sites from the 2018 image analysis, which is about 80% of the total Bareland in 2018. Likewise, 146 segments of an average area of 3.9 km2 of each segment were found to be potential mining sites. This implies that mining within the basin is threatening other LULC and hence, reclamation and restoration activities need to be intensified. The outcome of this research could facilitate technological strategies towards restoration projects within the Basin.