Browsing by Author "Nebiyu, Daniel Tiruneh"

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    Mathematical modelling of sediment yield from small catchments
    (University of Dar es Salaam, 1997) Nebiyu, Daniel Tiruneh
    This dissertation is the result of a research conducted in an attempt to study the suitability of systems type models in modelling sediment yield from small catchments. To serve the intended purpose a sediment model is developed by coupling a simple linear model with a sediment component. The model makes use of the antecedent precipitation index (API) of the catchment and a variable gain factor in order to appreciate the effect of the catchment wetness. Thus being a variable Gain Factor Model (VGFM) it can be related to that of a special form of Volterra-type nonlinear model as introduced by Amorocho and Orlob (1961). Data obtained from a small experimental catchment known as R-S is used to test the model. The catchment is an experimental catchment within the Washita River experimental watershed. It is located near Chickasha, Oklahoma, the United States. The available data contain precipitation; discharge, suspended sediment concentration, and sediment discharge for a period of twelve years (from 1966 to 1978). The results obtained on the basis of model efficiency and comparison of mobilized sediment indicate the suitability of the systems type model for modelling of sediment from small catchments.