Study of Physical Modeling And Empirical Bed Changes in Single Meandering River by Developing Shortcut Adi Prawito(1*), Suhardjono(2), Aniek Masrevaniah(3), Agus Suharyanto(3)
(1)Doctoral Program in Civil Engineering,Faculty of Engineering, University of Brawijaya, Indonesia
(2)Promotor of Doctoral Program in Civil Engineering, Faculty of Engineering, University of Brawijaya, Indonesia
(3)Co-Promotor of Doctoral Program in Civil Engineering, Faculty of Engineering, University of Brawijaya, Indonesia
*a_prawito[at]yahoo.co.id
Abstract
The development in river channels are such as groundsill, shortcut, river normalization and more increasing sand retrieval will change the balance of the river and it will continue to seek new adjustment until the riverbed is stable and dynamic. River handling by developing shortcut causes a lot of new problems. Problems that occur included lowering river water surface, uncontrolled erotion of the river bed and infrastructure damage due to changes in hydraulic behavior and sedimentation characteristic.
To determine the changes in the river bed that occur in a single meandering river with the angle of 90 degree by developing shortcut, a study was carried out covering hydraulic behavior and sedimentation characteristic. The approach used is to make a physical model by testing the MPM empirical method.
Physical and empirical modeling in this study were carried out with smooth sand bed material. Flow discharge that enters to the model used with various input discharge, that is Q = 2.183 lt/s, Q = 2.997 lt/s, Q = 3.891 lt/s and Q = 4.858 lt/s. After running the physical model, analysis of the calculation of sediment volume at the control point were carried out using the MPM method ( Meyer-Peter and Muller). Then it was carried out sediment control at bends and shortcut between the physical model and the MPM empirical calculation.
The results of physical modeling using the MPM empirical method test on several treatments above, shortcut development is very influential to lowering river water surface. The sediment control at bends and shortcut show the same trend between the physical model and the MPM empirical calculation, that is, at the bend there is a sediment derivation from the first flow test, then in the test there is an escalation in sediment transport. Whereas in the shortcut, there was an escalation in sediment from the first flow test, then in the next flow test there was a derivation in sediment even though the discharge was increased.
Keywords: Shortcut, Single meandering river, Physical Model, Empirical Method of MPM, Bed Material of Smooth Sand, Sediment Transportation
