IRRIGATION ENGINEERING "This page is Intentionally Left Blank" IRRIGATION ENGINEERING Editor R.N. Reddy ff:d GENE TECH 2010 Gene-Tech Books New Delhi - 110 002 2010, © Publisher InformatlOlJ contall1cd in tillS work has been published by Gene-Tech Books and has been obtamed by Its allthor(s)/editor(s) from sOllrces belzeved to be reliable and are correct to the best of their knowledge. However, the publisher and its autllOr(s) make no representation of warranties with respect of aCCllracy or completeness of the contents of this book, and shall 111 no event be lzable for any efrors, omissIOns or damages arzsing out of use of tillS l1l/omzatlOn and specifically disclaim any implied warranties or merchantability or fitness for any particular purpose. All riglzts resaved. Including the rigllt to trallslate or to reproduce tillS book or parts thereof except for brief quotatIOns in entzcal reviews. ISBN 81-89729-98-5 ISBN 978-81-89729-98-1 Published by GENE-TECH BOOKS 4762-63/23, Ansari Road, Darya Ganj, NEW DELHI - 110 002 Phone: 41562849 e-mail:
[email protected] Printed at Chawla Offset Printers New Delhi - 110 052 PRINTED IN INDIA Preface Irrigation involves the artificial application of water to soil, usually for assisting the growth of crops in dry areas or where there is a shortage of rainfall. As the process of agriculture becomes increasingly mechanised, the application of scientific methods and technology to the procedure of irrigation comes as no surprise. With agricultural yields dwindling and demand for food increasing, the pressure on agriculture is immense and no stone is to be left unturned in meeting demands and expectations. Effective irrigation, enhanced pertinent technologies, thereby provides a most lucrative source for making agriculture profitable and worthwhile. This text has been written as a manual guiding agricultural engineers on the principles and concepts which define irrigation engineering. Elaborating upon the tools, technologies and techniques which are essential to the field, the text takes a look at the types of irrigation, including surface, localised and sprinkler systems, and how they are changing agriculture itself by making it more scientific. In addition to it the challenges faced by irrigation systems including those of entrophication, water pollution, depletion of underground aquifers, etc., are also discussed. Current trends and development have been analysed as well as the future prospects and opportunities. RN. Reddy "This page is Intentionally Left Blank" Contents Preface v 1. Importance of Irrigation Engineering 1 2. Estimation of Irrigation Demand 35 3. Irrigation Schemes and Methods 47 4. Modern Canal Operation Techniques 71 5. Design of On-demand Irrigation Systems 111 6. Mapping Water Networks 125 7. Drainage Pipes and Accessories 143 8. Drainage and Disposal Systems 179 9. Surface and Subsurface Drainage 201 10. Installation and Maintenance of Drainage Materials 11. Evaluation of Irrigation Project 239 255 Bibliography 269 Index 271 "This page is Intentionally Left Blank" 1 Importance of Irrigation Engineering Irrigation involves artificially providing crops with water. This technique is used in farming to enable plants to grow when there is not enough rain, part