Modelling past, present and future sediment yield trends in river Watari, Kano State (1980-2030): a scenario based approach

Abstract

Soil and water are essential to human existence on earth. This study evaluates the sediment yield across Watari River using the Soil and Water Assessment Tool (SWAT) model. The model utilized a digital elevation model DEM to extract the river network, basin delineation, and sub-basin division. The result shows a temporal trend that increased from 0.80 tons/ha in 1980 to 1.08 tons/ha in 2000. There was a decrease in the amount of sediment generated in 2010 with a value of 0.66 tons/ha from 1.08 tons/ha. This could be attributed to the soil conservation practices such as afforestation, terracing among others. In the year 2020, there was an increase in the amount of sediment yield generated in the basin from 0.66 tons/ha to 0.85 tons/ha and it will continue to increase to 1.02 tons/ha in 2030, going by the change of 0.7 tons/ha annually. This implies that cultivated areas have increased and will continue to increase, leading to an increase in soil erosion which in turns generates more sediment in the basin. Lastly, the SWAT helps to map and identify erosion hotspot areas in each of the epoch which might require soil conservation measures like planting of vegetation, terracing, construction of check dams, among others.