1. CE Introduction - · PDF file3.8 Horner and Llyod’s Method ... 7.3 Gumbel’s...
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Publications Comprehensive Theory with Solved Examples and Practice Questions Engineering Hydrology Civil Engineering
Transcript of 1. CE Introduction - · PDF file3.8 Horner and Llyod’s Method ... 7.3 Gumbel’s...
Publications
Comprehensive Theory
with Solved Examples and Practice Questions
EngineeringHydrology
Civil Engineering
MADE EASY Publications
Corporate Office: 44-A/4, Kalu Sarai (Near Hauz Khas Metro Station), New Delhi-110016E-mail: [email protected]: 011-45124660, 8860378007
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Engineering Hydrology© 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: 2015Second Edition (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 Engineering Hydrology. 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 Engineering Hydrology 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 ‘Precipitation, Abstractions from Precipitations, Stream Flow Measurement,
Surface Water Hydrology (Runoff), Hydrographs, Floods, Flood Routing, Ground Water, Hydrometeorology’ 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 1Introduction .....................................................1 Introduction ...................................................................... 1
1.1 The Hydrologic Cycle ..................................................... 1
1.2 Catchment Area ............................................................... 4
1.3 Water Budget Equation ................................................ 5
1.4 Residence Time ............................................................... 7
Chapter 2Precipitation .................................................. 10 Introduction ....................................................................10
2.1 Favourable Conditions for Precipitation ...............10
2.2 Forms of Precipitation .................................................11
2.3 Types of Precipitation ..................................................12
2.4 Types of Cyclone ...........................................................12
2.5 Measurement of Precipitation .................................13
2.6 Measurement of Snowfall .........................................14
2.7 Types of Gauges ............................................................14
2.8 Other Methods of Precipitation Measurement ..18
2.9 Raingauge Network .....................................................18
2.10 Optimal Number of Raingauges (N) ......................19
2.11 Estimation of Missing Data ........................................21
2.12 Inconsistency of Record .............................................22
2.13 Presentation of Rainfall Data ....................................26
2.14 Mean Precipitation Over an Area ............................28
2.15 Depth Area Duration (DAD) Relationship ............33
2.16 Frequency of Point Rainfall .......................................36
2.17 Intensity Duration Frequency Curves ....................37
2.18 Index of Wetness ...........................................................39
2.19 Drought ............................................................................39
2.20 Probable Maximum Precipitation (PMP) ..............40
Objective Brain Teasers .................................................41
Conventional Practice Questions........................47
Chapter 3Abstractions from Precipitations ............50 Introduction .....................................................................50
3.1 Evaporation .....................................................................50
3.2 Interception ....................................................................59
3.3 Transpiration...................................................................61
3.4 Evapotranspiration .......................................................61
3.5 Depression Storage ......................................................63
3.6 Percolation ......................................................................64
3.7 Infiltration ........................................................................64
3.8 Horner and Llyod’s Method.......................................71
3.9 Infiltration Indices .........................................................82
Objective Brain Teasers .................................................87
Conventional Practice Questions ...............................80
Chapter 4Streamflow Measurement .......................82 Introduction .....................................................................82
4.1 Gauging Site ...................................................................83
4.2 Stage ..................................................................................83
4.3 Measurement of Velocity ...........................................85
4.4 Direct Method of Discharge Measurement .........87
4.5 Indirect Method of Discharge Measurement .....96
4.6 Stage-Discharge Relationship ............................... 103
Objective Brain Teasers .............................................. 103
Conventional Practice Questions ............................ 105
Chapter 5Surface Water Hydrology (Runoff) ........107 Introduction .................................................................. 107
5.1 Natural Flow ................................................................. 108
5.2 Factors affecting the Distribution of Runoff
in Time ........................................................................... 109
Engineering HydrologyContents
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5.3 Time of Concentration (TOC) ................................. 112
5.4 Travel Time or Time of Flow .................................... 112
5.5 Isochrone ...................................................................... 112
5.6 Water Year ..................................................................... 113
5.7 Runoff Characteristics of Streams ........................ 113
5.8 Yield ................................................................................ 114
5.9 Watershed Simulation .............................................. 114
5.10 Flow-Duration Curve ................................................ 114
5.11 Flow-Mass Curve ........................................................ 117
5.12 Calculation of Reservoir Capacity ........................ 118
5.13 Determination of Optimum Demand Rate ...... 124
5.14 Variable Demand ....................................................... 125
Objective Brain Teasers .............................................. 126
Conventional Practice Questions ............................ 127
Chapter 6Hydrographs ...........................................130 Introduction .................................................................. 130
6.1 Factors Affecting Flood Hydrograph .................. 131
6.2 Factors Affecting Shape of Hydrograph ............ 132
6.3 Components of Hydrograph ................................. 134
6.4 Base Flow Separation ............................................... 135
6.5 Effective Rainfall ......................................................... 136
6.6 Unit Hydrograph ........................................................ 140
6.7 Distribution Graph .................................................... 162
6.8 Synthetic Unit Hydrograph - Snyder’s Method ....166
6.9 Indian Equations For Synthetic
Unit Hydrograph ........................................................ 172
6.10 Dimensionless Unit Hydrograph .......................... 173
6.11 Triangular Unit Hydrograph ................................... 173
6.12 Instantaneous Unit Hydrograph (IUH) ............... 174
6.13 Other Types of Hydrograph ................................... 174
Objective Brain Teasers .............................................. 175
Conventional Practice Questions ............................ 181
Chapter 7Floods ....................................................188 Introduction .................................................................. 188
7.1 Types of Flood ............................................................. 188
7.2 Estimation of Flood Peak......................................... 189
7.3 Recurrence Interval (T) ............................................ 200
7.3 Gumbel’s Method ...................................................... 210
7.4 Safety Factor ................................................................ 221
Objective Brain Teasers .............................................. 223
Conventional Practice Questions ............................ 226
Chapter 8Flood Routing .........................................230 Introduction .................................................................. 230
8.1 Uses of Flood Routing .............................................. 230
8.2 Flood Wave ................................................................... 231
8.3 Types of Flood Routing ............................................ 232
8.4 Factors Used in Flood Routing .............................. 233
8.5 Available Storage Curve .......................................... 233
8.6 Basic Equation used in Flood Routing ................ 233
8.7 Relationship between Discharge and Storage .....234
8.8 Time of Redistribution ............................................. 235
8.9 Time of Translation .................................................... 235
8.10 Various Method of Reservoir Routing ................ 235
8.11 Hydrological Channel Routing .............................. 241
8.12 Flood Control ............................................................... 246
Objective Brain Teasers .............................................. 249
Conventional Practice Questions ............................ 252
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