Comprehensive Theory

with Solved Examples and Practice Questions

IrrigationEngineering

Civil Engineering

Publications

MADE EASY Publications

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Irrigation Engineering© Copyright by MADE EASY Publications.All rights are reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photo-copying, recording or otherwise), without the prior written permission of the above mentioned publisher of this book.

First Edition: 2014Reprint : 2015Reprint (Revised and Updated): 2016

© All rights reserved by MADE EASY PUBLICATIONS. No part of this book may be reproduced or utilized in any form without the written permission from the publisher.

Publications

This book was motivated by the desire to further the evolution of a concise

book on Irrigation Engineering. Keeping in focus the importance of this

subject in GATE and ESE, we have done a proper study and thereafter

developed the content of the book accordingly. This edition has an

expanded discussion of all relevant topics in the subject.

Initially, we compiled the perceptions of our students on their problems

in GATE and ESE while dealing with the questions from this subject. We

identified their various problems like- lack of fundamentals of the subject,

difficulty in solving simple solutions, shortage of a complete study package,

etc. These strengthened our determination to present a complete edition of Irrigation Engineering textbook.

The book addresses all the requirements of the students, i.e. comprehensive coverage of theory, fundamental

concepts, objective type problems and conventional problems, articulated in a lucid language. The concise

presentation will help the readers grasp the concepts with clarity and apply them with ease to solve problems

quickly. The books not only covers the entire syllabus of GATE and ESE, but also addresses the need of many other

competitive examinations. Topics like ‘Irrigation Principles, Practices and Project, Soil, Water, Plant Relationship,

Water Requirements of Crops, Water Logging and Lining of Canal, Canal Irrigation, Sediment Transport and Canal

Design, Canal Regulation Work, Canal Headworks and Seepage Theory, River Training and CD Works, Dams,

Spillways, Energy Dissipation and Spillway Gates’ are given full coverage in line with our research on their importance

in competitive examinations.

We have put in our sincere efforts to present elaborate solutions for various problems, different problem solving

methodology, some useful quick techniques to save time while attempting MCQs without compromising the accuracy

of answers. A summary of important points to remember is added at the end of each topic. For the convenience

of readers, points to remember are specifically highlighted in the form of a note- both in theory as well as solved

examples. At the end of each chapter, sets of practice question are given with their keys, that will allow the readers

to evaluate their understanding of the topics and sharpen their problem solving skills.

Our team has made their best efforts to remove all possible errors of any kind. Nonetheless, we would highly

appreciate and acknowledge if you find and share with us any printing, calculation and conceptual error.

It is impossible to thank all the individuals who helped us, but we would like to sincerely thank all the co-authors,

editors and reviewers for putting in their efforts to publish this book. We also express our thanks to MADE EASY

publications for completing and publishing the book on time.

With Best Wishes

B. Singh

CMD, MADE EASY

Preface

Chapter 1Irrigation Principles, Practices and Project .. 1

1.1 Definition of Irrigation ..............................................1

1.2 Main Concerns in Irrigation .....................................1

1.3 Advantages of Irrigation ..........................................1

1.4 Disadvantages of Irrigation .....................................2

1.5 Systems of Irrigation ..................................................2

1.6 Surface and Sub Surface Irrigation .......................2

1.7 Methods of Irrigation ...............................................3

1.8 Irrigation Project Survey...........................................9

1.9 Important Irrigation Projects in India ..................9

Objective Brain Teasers ............................................ 10

Conventional Practice Questions .......................... 11

Chapter 2Soil, Water, Plant Relationship ................. 12

2.1 Brief Understanding................................................ 12

2.2 Water Holding Capacity of the Soil ................... 12

2.3 Capillary Pores and Non-Capillary Pores ......... 13

2.4 Classification of Soil Water .................................... 13

2.5 Soil Moisture Tension (SMT) ................................. 13

2.6 Soil Moisture Stresses (SMS) ................................ 14

2.7 Soil Moisture Constants ......................................... 14

2.8 Formula for Depth of Water Stored in the Root

Zone of the Soil ........................................................ 15

2.9 Standard of Irrigation Water ................................ 18

Objective Brain Teasers ............................................ 21

Conventional Practice Questions .......................... 22

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Irrigation EngineeringContents

Chapter 3Water Requirements of Crops ................24 3.1 Introduction ............................................................... 24

3.2 Cropping Seasons in India .................................... 24

3.3 Duty and Delta .......................................................... 25

3.4 Crop Period and Base Period ............................... 25

3.5 Relation between Duty and Delta ..................... 26

3.6 Important Definition Linked with Water

Requirements of Crops .......................................... 26

3.7 Irrigation Efficiencies .............................................. 28

3.8 Irrigation Requirements of Crops....................... 30

3.9 Consumptive Use (Cu) or Evapotranspiration

(ET) ................................................................................ 32

Objective Brain Teasers ...........................................43

Conventional Practice Questions .......................... 45

Chapter 4Water Logging and Lining of Canal ......... 47 4.1 Water Logging .......................................................... 47

4.2 Causes of Water Logging ...................................... 47

4.3 Effects of Water Logging ....................................... 47

4.4 Remedial Measures Adopted for Controlling

Water Logging .......................................................... 47

4.5 Losses in Canal .......................................................... 48

4.6 Leaching ...................................................................... 48

4.7 Land Drainage ........................................................... 49

4.8 Lining of Canal .......................................................... 53

4.9 Types of Lining of Canal ........................................ 54

4.10 Design of Lined Canal ............................................ 54

4.11 Economics of Canal Lining ................................... 58

Objective Brain Teasers ............................................ 61

Conventional Practice Questions .......................... 62

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Chapter 5Canal Irrigation, Sediment Transport and Canal Design .............................................. 63 5.1 Canal Irrigation ......................................................... 63

5.2 Classification of Irrigation Canals ....................... 63

5.3 Canal Alignment ...................................................... 64

5.4 Warabandhi Method ............................................... 64

5.5 Layout of an Irrigation Canal Network ............. 66

5.6 Sediment Transport ................................................ 67

5.7 Shield’s Entrainment method for design of non

scouring stable channels ...................................... 68

5.8 Alluvial Channels and Non-Alluvial Channels ....72

5.9 Design of Alluvial Channels in India ................. 73

5.10 Kennedy’s Theory..................................................... 73

5.11 Lacey’s Regime Theory ........................................... 74

5.12 Comparison of Lacey and Kennedy Theories .....76

Objective Brain Teasers ............................................ 79

Conventional Practice Questions .......................... 83

Chapter 6Canal Regulation Work ............................. 84 6.1 Introduction .................................................................................84

6.2 Canal Fall ........................................................................................84

6.3 Types of Canal Falls...................................................................85

6.4 Canal Regulators........................................................................88

6.5 Canal Escapes ..............................................................................89

6.6 Types of Canal Escapes ..........................................................90

6.7 Canal Outlets ...............................................................................91

6.8 Types of Canal Outlets ............................................................91

6.9 Parameters for Studying the Behaviour of Outlets ......92

Objective Brain Teasers ............................................................94

Conventional Practice Questions ........................................95

Chapter 7Canal Headworks and Seepage Theory .. 96 7.1 Introduction ............................................................... 96

7.2 Location of Headworks .......................................... 97

7.3 Components Parts of a Diversion Headworks ...98

7.4 Seepage Theories...................................................102

Objective Brain Teasers ..........................................107

Conventional Practice Questions ........................110

Chapter 8River Training and CD Works .................. 111 8.1 Behaviour of Rivers................................................................111

8.2 Classification of Rivers .........................................................111

8.3 Meandering Phenomena and Meandering

Parameter ...................................................................................113

8.4 River Training, Classification and Objectives ..........114

8.5 Methods of River Training .................................................115

8.6 Cross Drainage Works ..........................................................121

8.7 Types of CD Works .................................................................121

8.8 Features of Design of CD Works ....................................125

8.9 Methods Used for Designing Channel Transition .....125

Objective Brain Teasers .........................................................128

Conventional Practice Questions .....................................130

Chapter 9Dams, Spillways, Energy Dissipation and Spillway Gates .......................................... 132 9.1 Dams and its Classification .................................132

9.2 Selection of Site for Dam.....................................133

9.3 Gravity Dams ...........................................................133

9.4 Forces Acting on a Gravity Dam ......................134

9.5 Modes of Failure (Stability Requirements) ....139

9.6 Stability Analysis (Gravity method or 2D

method).....................................................................142

9.7 Elementary Profile of a Gravity Dam ...............144

9.8 Spillways ...................................................................147

9.9 Energy Dissipators .................................................153

9.10 Types of Gates for Spillway Crests ...................156

Objective Brain Teasers ..........................................159

Conventional Practice Questions ........................162

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