Siltation characteristics of lower Rufiji flood-plain and delta.

The importance of floods of different magnitude on the flood-plain sedimentation can be estimated from sedimentation measurements carried out during a series of floods. However, because these measurements represent the sediment accumulation during the flood, they cannot be used to estimate the importance of individual flood stages as sediment deposition. In this study, the importance of different flood stages on flood-plain sedimentation rate was assessed from the estimated overbank flow, and the sediment load carried by such a discharge was estimated and computation of the depth of the sediment transported was calculated, taking the density of dry sediment to be 2050kg/m3. Comparison of the results obtained with additional information on sediment transport by flood, using Muskingum-cunge model to route the flood from Stiegler's Gorge down to Msomeni was made. This study also took the rate of sedimentation on the delta into consideration. 2D mathematical model was developed in this study to study the fate and sediment transport into the Rufiji delta. The hydrodynamic and transport equations are solved numerically by the finite volume method. The equations are integrated over the flow depth assuming that the flow is incompressible and homogenous. Vertical flow is considered negligible resulting in a hydrostatic pressure distribution.