Analysis of sediment movement at riverbank : erosion and deposition

Abstract

Understanding of river system that have experience various forcing mechanism such as deposition and erosion is a major concern. Deposition impinges directly on many aspects especially agricultural because the study areas are near to paddy field. Due to this problem, a study was carried out to determine the sediment shear stress, critical shear stress and characteristics of sediment load. Sediment shear stress, τo was calculated by Prandtl-Von Karman equation and critical shear stress, τc were figured by calculation depending on plasticity index (PI) and median particle size (D50). Results figured that sediment shear stress, τo at point one value is 5.985×10-3 N/m2, while critical shear stress, τc gave 3.112 N/m2, and 3.131 N/m2 respectively with calculation depending on plasticity index (PI) and median particle size (D50). At the second point, sediment shear stress, τo shows 8.385×10-3 N/m2. Meanwhile, critical shear stress, τc that depends on plasticity index (PI) is equal to 2.574 N/m2 and 3.029 N/m2 that is depend on median particle size (D50). Results for the third point figured that sediment shear stress, τo value is 0.0152 N/m2, while critical shear stress, τc gave 3.489 N/m2, and 3.151N/m2 respectively with calculation depending on plasticity index (PI) and median particle size (D50). Both method at all the three point showed critical shear stress, τc were greater than shear stress, τo (τc>τc). It shows that deposition happened at this study area. Besides of the regular maintenances, soft engineering techniques were suggested to control the deposition process from occur.