Author(s): Krishna R. Pathak; Koichi Suzuki; Akihiro Kadota; Yojiro Sakata
Linked Author(s):
Keywords: Sabo dam; Depositional pattern; Debris flow; Mountain river; Natural dam
Abstract: Rivers, which flow through mountain gorges of steep and weak valley sides and landslide- prone formation, are likely to be blockaded by natural dams. It is a prevalent situation in Nepal every year usually during rainy season. Present paper discusses on sediment deposition pattern of the debris flow emanated from the collapse of natural dam upstream of the sabo dam and makes an effort to simulate the sediment deposition pattern. In this study, sabo dam contains a fixed volume of debris produced by collapse of natural dam. Natural dams, trapezoidal in shape and downstream frontal slope nearly equal to the angle of repose of dam forming materials, were formed by using a non-uniform mixture of sediments having mean diameter 5. 43 mm in the experimental channel. The bed slope of the experimental channel was 10. 2 degree. At the downstream end of the experimental flume a sabo dam, 20 cm high, was set to check the debris flow and make it deposited upstream of the dam. One-dimensional momentum and continuity equations applicable to the unsteady flow in open channel were employed to verify the experimental results. Total flow (sediment plus water discharge) graphs and deposition profiles of the sediments were calculated and compared with observed results.
Year: 2005