Numerical simulation of groyne placement in minimising Krueng Aceh river bank erosion

This paper presents the prediction of the flow velocity in a 575 meters-long reach of the Krueng Aceh river. It focused on the part of the riverbank where erosion occurred due to the pillars and bridge abutments. One alternative to reduce erosion is using groynes for regulation. The simulations were conducted using the Surface Water Modelling System program (SMS 11.2). The effects of the groynes on the flow changes causing erosion were determined by mathematical simulation of two-dimensional flow using RMA2. The calibration of RMA2 was undertaken by determining the Root-Mean-Square (RMS) error between the measured and mathematical model velocities. Nine scenarios of simulations have been done to investigate the effect of the groyne installation in reducing erosion in the river bend, in term of its length (L), and angle (α), according to river condition. From the simulation results, it can be concluded that the distribution of flow velocities towards the outer river bend for the perpendicular groyne of 9.0m long was smaller compared to the 7.0m one. The groyne with the angle of 10° and length of 7.0m was better in reducing the velocities at the outer riverbank than the 9.0m one. Whereas the groyne with 30° orientation and 9.0m long is better in reducing the eddy than that of the 7.0 m.