Analysis of sediment load under combined effect of rainfall and flow

Abstract

An increase in sediment load resulting from extreme weather event can affect the capacity of existing water infrastructure, for example, decreasing reservoir capacities, creating obstacles and reducing the navigation depth, or eroding bridge piers by scouring actions. A number of studies have been carried out on factors affecting sediment yield and transport but only a few studies being done on the combination of both rainfall and flow on the sediment load. Therefore, the aim of this study is to identify the impact on sediment load comprising of well-graded silica sand due to combined effect of flow and rainfall. This research has two objectives; firstly, to study the relationship between flow, rainfall, and sediment load and secondly to devise an experiment to investigate how combination of flow and rainfall could affect sediment load with the help of Advanced Environmental Hydrology System. Thirty-six sets of experiments were conducted on a 2 m long, 0.2 m wide and 0.15 m deep channel, moulded in the Armfield S12 MKII on a 1% constant slope with six different readings of rainfall ranging from 6 to 72 mm/hr and by varying the flow ranging from 0.5 to 3.0 L/min to observe the different trends and changes to sediment load when rainfall and flow varies. This experimental study demonstrates a combination of both rainfall and flow resulted in a stronger linear correlation with sediment load.