Author(s): S. B. Weerakoon; N. Tamai
Linked Author(s): S.B. Weerakoon
Keywords: Reservoir; Sedimentation; Modelling
Abstract: Sedimentation model for estimation of seasonal sedimentation in the rain fed tanks (reservoirs) in the minor irrigation systems in Sri Lanka is presented. The model is based on the subdivision of the catchment into hillslopes and application of a sediment transport capacity equation at hillslope scale and computation of sediment loads transported to the tank. Coarse and fine sediment loads due to hourly excess rainfall during a season are separately estimated. The model depends on less parameters and can be easily calibrated for a tank. The model calibration only requires measurements of coarse and fine sediment loads transported into the tank due to several rainfalls of different intensities from a representative subcatchment of the tank. Coarse sediment loads are measured by using a sediment trap installed across a ephemeral stream draining the subcatchment. Fine sediment loads are obtained by measuring the discharge and accompanied sediment concentrations over the sediment trap. The model is calibrated, verified and applied for a irrigation tank in Sri Lanka to estimate the seasonal sedimentation loads.
Year: 2003