MODELING THE CONTROL OF RIVER BEND BED EROSION BY INSTALLING IMPERMEABLE CRIBS

Characteristic of water flow in the river bend is very dynamic, on the erodible base river usually occurring erosion and sedimentation and the dynamic move and the river groove going be dynamic move. These conditions are dangerous and threatening to the infrastructure around it. The purpose of this research is to evaluate of cribs installation configuration that most effective in erosion control in the bending bed of the river. The method of this research is built impermeable cribs with four alternatives installation. With those four installation alternatives can be evaluated: first velocity reduction rate, and second erosion reduction rate and sedimentation increase on upstream of the cribs. And then be compared with erosion and sedimentation result from the Surface Water Modelling System (SMS) software simulation. In this case be simulated four alternatives installation impermeable cribs with 25 years return period design flood equivalent to 2, 440 m³/seconds. The results on each alternative of cribs installation configuration are monitored on five points observations to obtain: velocity reduce effectiveness, erosion reduce effectiveness and sedimentation increasing. The analysis and evaluation of four installations cribs alternative model has obtained the alternative model 1 are the most effective inflow velocity reduction and the alternative model 4 is best to reduce erosion. River bend bed erosion control should be used by combining alternative models 1 and 4.