Analysis of sediment load on meandering channel due to combined effect of rainfall and flow

Abstract

Topography, geology, climate change and anthropogenic activity are key factors for erosion that affects channel morphology. Water erosion leads to sedimentation. The study of sediment is important for the management of water quality, river structures as well as flood control. Erosion of soil by water poses a serious problem in terms of degradation of land and eutrophication of water. River or stream erosion is mainly caused by rainfall and streamflow as they detach soil particles and transport them as sediment. The meandering channel is common in most rivers or streams where it is formed by the deposition of sediments due to the depletion of water energy. Therefore, this study aims to analyse the sediment load under the combined effect of rainfall and flow for a meandering channel. This study was conducted based on the Advanced Environmental Hydrology System to determine the relationship among sediment load, rainfall and flow rate. Twenty-five sets of experiments were conducted on a 2 m long, 20 cm wide and 4 cm deep model meandering channel, moulded in the Armfield S12 MKII on a 1% constant slope. Five different rainfalls intensities (0.46 mm/hr, 1.39 mm/hr, 2.78 mm/hr, 3.70 mm/hr and 4.63 mm/hr) and five different flow rates (0.5 L/min, 1.0 L/min, 1.5 L/min, 1.75 L/min and 2.0 L/min) were used to analyse the different trends of sediment load with respect to rainfall and flow rate. This study shows that there is a correlation among rainfall, flow and sediment load. The erosion rate during lowest flow and rainfall is 4.75 g/min and for highest rainfall and flow is 70.2 g/min.