Importance Of Alluvial Rivers

1. INTRODUCTION

1.1 Introduction
“Anyone who can solve the problems of water will be worthy of two Nobel Prizes - one for Peace and one for Science”, stated by John F. Kennedy. Since the beginning of civilization, mankind has faced tribulations allied with river and its flow. With increase in utilization of water resources; flow in river channels are gaining significant importance among the research scholars. More and more complicated problems are encountered due to multipurpose use of alluvial rivers.
Flow velocity, Shear stress, and Unit Stream Power are important characteristics for the measurement of the behavior of the river. Quantification of flow velocity, shear stress, and Unit Stream Power is important both for engineering problems and for ecological assessments. All these characteristics depend on resistance which is due to roughness, area of the flow and slope of the channels and the relation between these four parameters is known as resistance relationship.
In simple form, flow velocity is defined as the displacement of water particles with respect to the time; shear stress refers to the force which is exerted by water on the channel bed; and stream power refers to the rate of energy dissipation against the bed and banks of a river per unit downstream length.
If the slope of the channel is steep, then the flow velocity is high. And in Gravel bed-rivers, if the discharge is increased due to high intensity rainfall, then this high velocity of flow results in large boulder movements, which may cause heavy destruction. So, if some obstruction is provided in the course of the river then the flow velocity and thus shear stress is reduced and less rate of energy dissipation.
In response to any change in the environ...

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... destruction caused to movement of heavy boulders, in case of high intensity rainfall.

1.4 Organisation Of Thesis
The chapters are organized in the following way:
Chapter-1- Description of introductory aspects of the topic studied, underlying objectives and description of the study area and the layout of the thesis.
Chapter-2- Presentation of a comprehensive review of literature
Chapter-3- Description of data collection and methodology adopted
Chapter-4- Study of flow velocity and its results and conclusion
Chapter-5- Study of Shear stress and its results and conclusion
Chapter -6- Study of Energy gradient slope and its results and conclusion
Chapter-7- Study of Stream Power and its results and conclusion
Chapter -8-Preliminary Structural Detailing and cost analysis of the piano key weir
Chapter-9- Presentation of conclusions and scope for future work