Role of Sediment in the Design and Management of Irrigation Canals
Role of Sediment in the Design and Management of Irrigation Canals

Author: Krishna P. Paudel

Publisher: CRC Press

Published: 2010-12-15

Total Pages: 0

ISBN-13: 9780415615792

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The performance of irrigation schemes that carry sediment laden water is often poor. Modern irrigation schemes are increasingly demand based, which means that the water flow in the canals is determined by the crop water requirements. Accordingly the flow in the canal network is not constant as the crop water requirement changes with the climate and the growing stages. Also the inflow of the sediment is not constant throughout the irrigation season. Such schemes, particularly having unlined canals in alluvial soils, are difficult to design and to manage without compromising the flexibility or maintenance cost. This research has made an in-depth assessment on the role of sediment in the design and management of an irrigation scheme by using the data of Sunsari Morang Irrigation Scheme, Nepal. An analysis of the velocity and shear stress distribution across a non-wide trapezoidal canal has been made to derive the correction factor for the sediment transport predictors. An improved approach based on a rational concept of the design of canals for sediment transport is proposed. By using the sediment transport model SETRIC, a water delivery plan has been designed and tested for changing water and sediment inflow conditions that can be implemented with the existing canal infrastructure. The research also shows that flexibility of operation and efficient sediment management are difficult to achieve at the same time. A compromise has to be made and this needs to be reflected in the design. All methods to transport, exclude or extract the sediment are temporary measures and just transfer the problem from one place to the other. A better understanding of sediment movement helps to identify the problems beforehand and to find the best possible solutions.

Reservoir Sedimentation
Reservoir Sedimentation

Author: G.W. Annandale

Publisher: Elsevier

Published: 1987-01-01

Total Pages: 233

ISBN-13: 0080870201

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Research on reservoir sedimentation in recent years has been aimed mainly at water resources projects in developing countries. These countries, especially in Africa, often have to cope with long droughts, flash floods and severe erosion problems. Large reservoir capacities are required to capture water provided by flash floods so as to ensure the supply of water in periods of drought. The problem arising however is that these floods, due to their tremendous stream power, carry enormous volumes of sediment which, due to the size of reservoirs, are virtually deposited in toto in the reservoir basin, leading to fast deterioration of a costly investment. Accurate forecasting of reservoir behaviour is therefore of the utmost importance.This book fills a gap in current literature by providing in one volume comprehensive coverage of techniques required to practically investigate the effects sediment deposition in reservoirs has on the viability of water resources projects. Current techniques for practically estimating sediment yield from catchments, estimating the volume of sediment expected to deposit in reservoirs, predicting sediment distribution and calculating scour downstream of reservoirs are evaluated and presented. The liberal use of diagrams and graphs to explain the various techniques enhances understanding and makes practical application simple. A major feature of the book is the application of stream power theory to explain the process of reservoir sedimentation and to develop four new methods for predicting sediment distribution in reservoirs.The book is primarily directed at practising engineers involved in the planning and design of water resources projects and at post-graduate students interested in this field of study.