FENOMENA GELOMBANG PASANG BONO DI MUARA SUNGAI KAMPAR

Abstract

When a river mouth has a flat converging shape and when the tidal is relatively high, the river may existence a tidal bore. A tidal bore found at Kampar River, called Bono, is basically a positive surge may travel long distances upstream about 60 km of the mouth. The occurrence of a bore has a significant impact on river systems. To understand flow characteristic where Bono exist, the hydraulic analysis is intended to recognize the water phenomenon throughout the observed Kampar River under the averaged velocities and the tides. The hydraulic analysis is carried out using HecRAS software. The hydraulic simulation gives information about water surface profile, velocity, and flow through the channel. Water surface fluctuations, resulting from simulation, are overlied wih field data. Bono phenomenon can be analog as undular hydraulics jump in steady state conditions, suggesting high shear stresses beneath the first wave crest. Consequently bed erosion and scour take place beneath the bore front while suspended matters may be carried upwards in the following wave motion. This sediment transport may affect changes of river morphology; creates some small islands in the river and bank erosion near Muda Island and mouth of Serkap River. These sediment deposits can be explored, however this sand mining should be managed and arranged to maintain the existence of Tidal Bore Bono. Flow simulation using Hec RAS model predicts flow fluctuations at same places where tidal bores Bono impact also significantly on ecosystems. Water Salinity near Muda Island is raised significantly 3 hours after the highest Tidal at Kampar Mouth, following near Sei Serkap an hour later. However at Tanjung Rengas, increasing of salinity is not important.