Modeling the suspended sediment yield in Lesotho rivers

The present work was carried out in the framework of the Lesotho-Italy cooperation project “Renewable Energy Maps for Lesotho,” launched in 2016, with the main purpose to produce a series of maps aimed to support the Government of Lesotho in planning and expanding the exploitation of renewable energy sources (wind, solar and hydro). A multiple regression model specifically developed for sediment yield assessment in Lesotho catchments is here presented with a view to contributing to the follow-up of development projects in the field of hydroelectric energy. The “Lesotho model,” based on observations at 16 gauging stations, takes into account the proportions of agricultural and sedimentary bedrock areas as explanatory variables. Statistical reliability tests proved the model robustness after previous models, developed at continental or sub-continental scale, revealed to be ineffective or hardly applicable. A map of simulated sediment yields at sub-catchment level is provided, as an example of model application.