Browsing by Author "Patrick, Philipo"

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    Application of a GIS-based channel network model (CCHEID) for the Pangani river system
    (University of Dar es Salaam, 2006) Patrick, Philipo
    Previous studies on soil erosion from the upland reaches the reservoir. Such low delivery ratio has been attributed to presence of low lands, takes, swamps, and mild channel thalweg slopes. Besides, some gauging flow stations such as IDCI in the main Ruvu River has been abandoned since the impoundment of Nyumba ya Mungu dam in 1968. Other workers have characterized Pangani River System an complex river network. A mathematical model called CCHEID that uses dynamic wave model and a number of sediment transport capacity equation to route flood and sediment were applied in the Pangani River System. In order to complete flow discharges data for abandoned gauging station, IDCI, a complex rating curve was developed. A natural river system was calibrated using flow and/or sediment flow data from IDCI and ID8A gauging stations, which, are located within the study reach. The flow routing module was validated before and after the dam installation. Besides, comparing simulated and measured channel thalweg elevation after 37 years of Nyumba ya Mungu reservoir operations validated sediment routing module. The model performances during flow and/or stage calibration period according to Nash and Sutcliffe criterion R^2 are 80% for IDCI and (81% and 89.5%) for ID8A respectively, while validation period for IDCI is 52%. A qualitative assessment of the plots of simulated and measured sediment thalweg elevation has indicated that they are comparable. This study has also found that there is no significant sediment deposition in the upstream river reaches of the study area, but rather most sediment reaches into the reservoir and focuses in the main Pangani river channel within first 25 km from the dam.