Speaker
Description
Understanding land cover dynamics and their implications on sedimentation is critical for sustainable reservoir management in rapidly urbanizing catchments. This study assessed land cover changes from 1990 to 2030 across the Owabi, Barekese, and Odaso sub-catchments in Ghana and their impact on sedimentation risk and water supply sustainability. Classification models demonstrated robust performance, with overall accuracy (OA) ranging from 86% to 95% and strong Kappa coefficients (0.78 to 0.92), confirming model reliability. The land cover changes revealed significant declines in closed forest cover, primarily due to settlement expansion, agriculture, and illegal mining, with Owabi and Odaso experiencing the most substantial forest-to-settlement and forest-to-bareland transitions. Consequently, sedimentation risk scores (SRS) increased by 1.8, 2.5, and 3.6 folds for Owabi, Barekese, and Odaso, respectively, from their 1990 baselines, with Odaso experiencing the most rapid increase due to intense illegal mining activity. Forest degradation and weak buffer enforcement have exacerbated sediment influx into reservoirs, threatening water treatment operations and ecosystem services. The study highlights the urgency of preserving forest buffers, enforcing land-use regulations, and integrating land cover monitoring into sediment risk mitigation strategies. These findings are pivotal for informing policy and ensuring resilient potable water supply systems in urban Ghana.
Key words: Reservoir, Sedimentation, Land cover change, Assessment