FLOW SIMULATION OF BRAHMAPUTRA RIVER USING I D-MODELING APPROACH

Abstract

The flow resistance characteristics of an alluvial stream are highly complex, which warrant considerable research efforts. The dynamics of flow is further complicated in a natural stream due to wide differences in hydraulic properties and resistances of flow in the main channel and the subsidiary channels. The position of the free surface is likely to change with respect to time and space and also by the fact that the depth of flow, the discharge and the slopes of the channel bottom and of the free surface are interdependent An integrated study in Fluvial Hydraulics and Sediments Transport involves the analysis of the capacity of the river or channel to carry water and sediment, and the corresponding morphological changes in both the main channel and floodplain. Sediment transport in concise, replicates the various aspects of the dynamics of solid particle movement, properties of the transported materials, and characteristics of the transporting medium, which in turn, may be affected by the solids transported. The morphological changes of rivers are deeply interrelated with bed deformation and bank erosion because of the mutual relationship between water flow and sediment transport. A better understanding of these processes is very important in river engineering to prevent disasters due to flooding, to design and manage hydraulic structures, like bridges and water intake towers, and to maintain river ecosystems and the landscape for environmental engineering purposes. Reliable and quantitative estimate of the bed aggradation or degradation are very important in river engineering and management projects as well as accurately predicting the water surface elevations during floods in estimating flood related damage. Thus, engineers are greatly interested in accurately predicting the behavior of river under various flows and sediment loads so that better information can be obtained for the planning and design of river control structures, flood protection measures and other water diversion structures...