ROLE OF SEDIMENT TRANSPORT IN OPERATION AND MAINTENANCE OF SUPPLY AND DEMAND BASED IRRIGATION CANALS application to machai maira branch canals SARFRAZ MUNIR ROLE OF SEDIMENT TRANSPORT IN OPERATION AND MAINTENANCE OF SUPPLY AND DEMAND BASED IRRIGATION CANALS APPLICATION TO MACHAI MAIRA BRANCH CANALS Thesis committee Thesis supervisor Prof. dr. E. Schultz Professor of Land and Water Development UNESCO-IHE Institute for Water Education Delft, the Netherlands Thesis co-supervisor Dr. Chu Thai Hoanh Principal Researcher – Water Resources International Water Management Institute Vientiane, Lao PDR Other members Prof. dr. L. F. Vincent Wageningen University Wageningen, the Netherlands Dr. ir. A. J. F. Hoitink Wageningen University Wageningen, the Netherlands Prof. dr. D. P. Solomatine UNESCO-IHE Institute for Water Education Delft, the Netherlands Prof. dr. N. C. van de Giesen Delft University of Technology Delft, the Netherlands ROLE OF SEDIMENT TRANSPORT IN OPERATION AND MAINTENANCE OF SUPPLY AND DEMAND BASED IRRIGATION CANALS APPLICATION TO MACHAI MAIRA BRANCH CANALS Thesis Submitted in fulfilment of the requirements of the Academic Board of Wageningen University and the Academic Board of the UNESCO-IHE Institute for Water Education for the degree of doctor to be defended in public on Thursday, 24 February 2011 at 3 p.m. in Delft, the Netherlands by Sarfraz Munir Born in Narowal, Pakistan CRC Press/Balkema is an imprint of the Taylor & Francis Group, an informa business © 2011, Sarfraz Munir All rights reserved. No part of this publication or the information contained herein may be replaced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording or otherwise, without written prior permission from the publishers. Although care is taken to ensure the integrity and quality of this publication and the information therein, no responsibility is assumed by the publishers nor the author for any damage to property or persons as a result of operation or use of this publication and/or the information contained herein. Published by CRC Press/Balkema PO Box 447, 2300 AK Leiden, the Netherlands e-mail: [email protected] www.crcpress.com - www.taylorandfrancis.co.uk - www.ba.balkema.nl ISBN 978-0-415-66947-4 (Taylor & Francis Group) ISBN 978-90-8585-850-8 (Wageningen University) Table of contents TABLE OF CONTENTS ................................................................................................ V ACKNOWLEDGEMENT .............................................................................................. XI SUMMARY ................................................................................................................ XIII 1. INTRODUCTION AND BACKGROUND ................................................... 1 1.1 BACKGROUND ................................................................................................... 1 1.2 RATIONALE OF THE STUDY ................................................................................ 2 1.3 SCOPE OF THE STUDY ........................................................................................ 3 1.4 RESEARCH QUESTIONS ...................................................................................... 3 1.5 RESEARCH HYPOTHESIS ..................................................................................... 4 1.6 OBJECTIVES ....................................................................................................... 4 1.7 INTRODUCTION OF THE THESIS .......................................................................... 4 2. INDUS BASIN IRRIGATION SYSTEM IN PAKISTAN ............................ 7 2.1 GENERAL INFORMATION ABOUT PAKISTAN ....................................................... 7 2.2 SOCIO-ECONOMIC SETTINGS OF THE COUNTRY .................................................. 8 2.3 WATER RESOURCES ........................................................................................... 8 2.4 INDUS BASIN IRRIGATION SYSTEM .................................................................... 9 2.5 HISTORY OF IRRIGATION IN THE INDUS BASIN ................................................... 9 3. SEDIMENT TRANSPORT AND FLOW CONTROL IN IRRIGATION CANALS ...................................................................................................... 13 3.1. GENERAL INFORMATION ON SEDIMENT TRANSPORT AND MODELLING ............. 13 3.1.1 Incipient motion ........................................................................................ 13 3.1.2 Bed load sediment transport ..................................................................... 14 3.1.3 Suspended sediment transport ................................................................... 15 3.1.4 Total sediment load ................................................................................... 15 3.2. EVALUATION OF SEDIMENT TRANSPORT FORMULAE ........................................ 16 3.3. SEDIMENT TRANSPORT MODELLING................................................................. 17 3.4. SEDIMENT TRANSPORT MODELLING IN IRRIGATION CANALS ............................ 19 3.5. SEDIMENT MANAGEMENT IN IRRIGATION CANALS ........................................... 20 3.5.1 Sediment control at intakes ....................................................................... 21 3.5.2 Sediment diverters (silt excluders) ............................................................ 22 3.5.3 Sediment ejectors ...................................................................................... 23 3.5.4 Settling basins ........................................................................................... 25 3.5.5 Sediment control by canal design approach ............................................. 25 3.5.6 Operation and maintenance of silt affected irrigation canals ................... 29 3.6. FLOW CONTROL IN IRRIGATION CANALS .......................................................... 30 3.6.1 Upstream control ...................................................................................... 30 3.6.2 Proportional control ................................................................................. 30 3.6.3 Downstream control .................................................................................. 30 vi Role of sediment transport in operation and maintenance of supply and demand based irrigation canals 3.7. HYDRAULICS OF DOWNSTREAM CONTROL SYSTEM ......................................... 31 3.8. DESIGN CRITERIA ............................................................................................ 34 3.9. FLOW CONTROL ALGORITHMS ......................................................................... 38 3.9.1. Supervisor Control and Data Acquisition System ......................................... 39 3.9.2. Proportional Integral Derivative (PID) control ........................................... 40 4. SEDIMENTATION IN TARBELA RESERVOIR AND ITS EFFECTS ON PEHURE HIGH LEVEL CANAL ......................................................... 41 4.1. SEDIMENTATION OF RESERVOIRS IN THE WORLD ............................................. 41 4.2. TARBELA DAM ................................................................................................ 41 4.3. SEDIMENTATION IN TARBELA RESERVOIR ....................................................... 44 4.3.1 Water availability at Tarbela Dam ........................................................... 44 4.3.2 Sediment inflow to Tarbela Reservoir ....................................................... 44 4.3.3 Tarbela Reservoir operation ..................................................................... 46 4.3.4 Sediment trapping in the reservoir and status of storage capacity ........... 46 4.3.5 Accumulated sediment deposition in Tarbela Reservoir ........................... 47 4.4. DEVELOPMENT OF SEDIMENT DELTA IN A RESERVOIR ..................................... 49 4.4.1 Siltation process in reservoirs ................................................................... 49 4.4.2 Formation of a delta ................................................................................. 49 4.4.3 Factors affecting sediment delta movement .............................................. 50 4.4.4 Reworking of the delta .............................................................................. 51 4.5. ANALYSIS OF THE SEDIMENT DELTA IN TARBELA RESERVOIR ......................... 51 4.6. PROSPECTS OF SEDIMENT MANAGEMENT ......................................................... 53 4.7. TARBELA DAM AND PEHURE HIGH LEVEL CANAL .......................................... 54 5. HYDRODYNAMIC BEHAVIOUR OF MACHAI MAIRA AND PEHURE HIGH LEVEL CANALS ............................................................. 57 5.1. BACKGROUND ................................................................................................. 57 5.2. OBJECTIVES OF THE HYDRODYNAMIC MODELLING .......................................... 58 5.3. METHODS AND MATERIALS ............................................................................. 58 5.3.1. Irrigation infrastructure ............................................................................... 58 5.3.2. System operations ......................................................................................... 62 5.3.3. Crop Based Irrigation Operations (CBIO) ................................................... 62 5.3.4. Discharge and water level controls .............................................................. 63