Spatio-temporal Variability Modelling of Sediment Yield in a Semi Arid River Basin: The Swat Approach

Charles Gyamfi, Julius Musyoka Ndambuki, and Ramadhan Wanjala Salim

Keywords

Land use/land cover change, Olifants Basin, Sediment yield, Spatio-temporal

Abstract

Anthropogenic activities in river basins have culminated into land use and land cover changes (LULCCs) resulting in environmental consequences of sediment generation. Understanding the role that LULCCs play in the dynamics of sediment yield would greatly enhance decision making processes that borders on land use and water resources management. We investigated the impacts of LULCCs on sediment yield dynamics through an integrated approach of hydrologic modelling and principal component analysis (PCA). A three phase land use scenario (2000, 2007 and 2013) employing the “fix-changing” method was used to simulate the sediment yield of the Olifants Basin. Annual sediment yield for the basin for 2000, 2007 and 2013 were respectively 946.76 t/km2.a, 1110.02 t/km2.a and 1408.27t/km2.a. Our results indicate that sediment yield dynamics in the study area is significantly attributed to the changes in agriculture, urban and forested lands. Changes in agriculture and urban lands positively influenced sediment yield dynamics of the Olifants Basin. On the contrary, forested areas had a negative relationship with sediment yield indicating less sediment yield from these areas. The output of this research work provides a simplistic approach of evaluating the impacts of land use changes on sediment yield. The tools and methods used are relevant for policy directions on land and water resources planning.

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