HYDROLOGY OF DISASTERS

Water Science and Technology Library VOLUME24

Editor-in-Chief v. P. Singh, Louisiana State University,

Baton Rouge, U.S.A.

Editorial Advisory Board

M. Anderson, Bristol, U.K. L.Beng~son,Lund,Sweden

A. G. Bobba, Burlington, Ontario, Canada S. Chandra, New Delhi, India M. Fiorentino, Potenza, Italy

W. H. Hager, Zürich, Switzerland N. Harmancioglu, Izmir, Turkey

A. R. Rao, West Lafayette, Indiana, U.S.A. M. M. Sherif, Giza, Egypt

Shan Xu Wang, Wuhan, Hubei, P.R. China D. Stephenson, Johannesburg, South Africa

HYDROLOGY OF DISASTERS

edited by

VUA Y P. SINGH Water Resources Program,

Department ofCivil and Environmental Engineering, Louisiana State University, Baton Rouge, U.SA.

SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

Library of Congress Cataloging-in-Publication Data

Hydrology of disasters I edited by V.P. Singh. p. cm. -- (Water science and technology library v. 24)

Includes index. ISBN 978-90-481-4715-1 ISBN 978-94-015-8680-1 (eBook) DOI 10.1007/978-94-015-8680-1 1. Floods. 2. Natural disasters. 1. Slngh. V. P. (Vljay P.)

11. Serles. GB1399.H88 1996 363' .492--dc20 96-18911

ISBN 978-90-481-4715-1

Printed on acid-free paper

All Rights Reserved © 1996 Springer Science+Business Media Dordrecht

Originally published by Kluwer Academic Publishers in 1996 Softcover reprint ofthe hardcover 1st edition 1996

No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical,

including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

to: ANITA, VINAY AND ART!

Table of contents

Preface

1 Disasters: Natural or Man-made v.P. Singh

1.1 Types of Disasters . . . . . . . . . . . . . . 1.1.1 Hurricanes and Tornadoes . . . . . .

1.2 Environmental and Hydrologic Consequences 1.2.1 Hurricanes. 1.2.2 Floods..... 1.2.3 Earthquakes..

1.3 Mitigation of Disasters . 1.3.1 Hurricanes. 1.3.2 Floods..... 1.3.3 Earthquakes..

2 Representativity of Extreme Wind Data J. Wieringa

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . 2.2 Wind phenomena Classified by the Wind Sspectrum . 2.3 What Are Representative Wind Data? . . . . . . . . 2.4 Representativity of "Potential Wind" . . . . . . . . . 2.5 Roughness Determination at Ordinary Wind Stations 2.6 Scale of Application of Station-Observed Wind . . . 2.7 Getting and Using Potential Wind Data ...... . 2.8 Distribution of Average Wind Speeds ....... . 2.9 Shelter Problems in Analysis of Extreme Stormwind speeds . 2.10 Some Available Studies of Extreme wind Speeds ..... .

3 Climate Change and Hydrological Disasters

xiü

1 1 5

13 13 14 14 14 15 16 16

19 19 20 22 23 25 28 30 31 33 35

M.A. Heran and N. W. Amell 41 3.1 Introduction . . . . . . . . . . . 41

3.1.1 Questions ........ 41 3.1.2 Concepts and definitions. 41 3.1.3 Is climate change a hydrological disaster? 42

3.2 The Greenhouse Effect, Climate Change and Hydrological Regimes. 43 3.3 Estimating the Impacts of Climate Change on Hydrological Characteristics 45

3.3.1 Introduction: Climate Change Scenarios . 45 3.3.2 Creating Climate Change Scenarios . 45 3.3.3 Equilibrium and Transient Scenarios. 48

3.4 Impacts of Climate Change on Floods . 48 3.4.1 Introduction . . . . . . . . . . 48 3.4.2 Factors Responsible for Floods 49

3.5 Impact of C1imate Change on Drought . 52

vii

viii Table oE Contents

3.5.1 Introduction . . . . . . . . . . . 52 3.5.2 Drought Definition. . . . . . . . 52 3.5.3 Factors Responsible for Drought . 54 3.5.4 Climatic Drought: A Shortage of Rainfall and Soil Water 55 3.5.5 Hydrological Drought: A Shortage of Runoff and Recharge 56 3.5.6 Water Resources Drought . . . 57 3.5.7 The Case of Sahel Drought. . . 58 3.5.8 Direct Effect of Carbon Dioxide 59

3.6 Conclusions . . . . . . . . . . . . . . 59

4 Extreme Floods F. Ashkar 63

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.2 Limitations of Statistical Methods for Estimating Design Floods . 64 4.3 Data Series Used in the Estimation of Design Floods .... 64

4.3.1 Brief Description of the POT Procedure . . . . . . . 65 4.3.2 Brief Comparison between AMF and POT Modelling 67

4.4 Flood "Quantiles" as Design Events . . . . . . . . . . . . 67 4.5 Statistical Hypotheses Used for Estimating Design Floods . 68 4.6 Some Remarks Pertaining to Flood Data . . . . . . . . . . 69 4.7 Choice of "D / E Procedure" for Flood Frequency Analysis 70

4.7.1 Choice of Statistical Distribution (D) .. . . . . . 71 4.7.2 Choice ofParameter-Estimation Method (e) . . . . 75 4.7.3 Sources of Uncertainty in Estimating Design Floods . 76 4.7.4 Statistical Tools for Selecting D / E Procedures 77

4.8 Regional Flood Frequency Estimation 77 4.9 Conclusions . . . . . . . . . . . . . . . . . . . . . . 79

5 Dam-Breach Floods D.L Fread 85

5.1 Introduction . . . . . . . . . . . . . . . . . 85 5.2 Breach Description . . . . . . . . . . . . . . 87

5.2.1 Mathematical Description ofBreach . 87 5.2.2 Concrete Dams. . . . . . . . . . 89 5.2.3 Earthen Dams . . . . . . . . . . 89 5.2.4 Assessment ofBreach Parameters 94

5.3 Dam-Breach Flood Routing .. . . 96 5.3.1 Dynamic Routing ..... 96

5.4 Dam-Breach Flood Routing Data. . . 112 5.4.1 Cross-Sectional Properties . . 112 5.4.2 Sinuosity Factors. . . . . . . 113 5.4.3 Manning n Friction Coefficients . 113 5.4.4 Levee Properties . . . . . . . . . . 115 5.4.5 Lateral Flows .......... . 116

5.5 Teton Dam-Breach Flood Case Study .. . 116 5.6 Uncertainties of Dam-Breach Flood Modeling . 121

5.6.1 Two-Dimensional Effects . . . 121 5.6.2 Cross-Sectional Degradation. . 121 5.6.3 Manning n . . . . . 122 5.6.4 Debris Effects . . . 123 5.6.5 Breach Properties . 123 5.6.6 Flow Losses . . . . 123

Table of Contents

6 Extreme Droughts M.L Kavvas anti M.L Antlerson

6.1 Introduction . . . . . . . . . . . . . . 6.2 Physical Systems Involved in a Drought

6.2.1 Atmospheric System . . . . 6.3 The Evolution of Extreme Drought .

6.3.1 Initiation. 6.3.2 Growth .. 6.3.3 Recovery. 6.3.4 Example.

6.4 Modeling an Extreme Drought . 6.4.1 General Circulation Models and Energy Balance Models 6.4.2 Energy Balance Model Parameterization. . . . . . . . . 6.4.3 Simulation of an Extreme Drought by an Energy Balance Climate

ix

127

· 127 · 129 · 129 · 135 · 135 .138 · 140 .140 · 145 · 146 · 147

Model . . . . . . . . 151 6.5 Discussion and Conc1usions . . . . . . . . . . . . . . . . . . . . . . . . 156

7 Mud and Debris Flows p.A. Johnson anti R.H. McCuen

7.1 Introduction . . . . . . . . . . . . . . . . . . . 7.2 Physical Processes . . . . . . . . . . . . . . . .

7.2.1 Factors Affecting Debris Flow Initiation . 7.2.2 Laboratory and Mathematical Studies . .

7.3 Methods of Prediction: When, Where, and How Much . 7.3.1 Magnitude........ 7.3.2 Frequency of Occurrence ..

7.4 Debris Flow Mitigation ...... . 7.4.1 Warning Systems ..... . 7.4.2 Passive Mitigation Measures . 7.4.3 Active Mitigation Measures .

7.5 Statistical Modeling of Debris Flows . 7.5.1 The Regionalization Process . 7.5.2 Regionalization ofDebris Volumes 7.5.3 Data Requirements for Regionalization

7.6 Conclusions . . . . . . . . . . . . . . . . . .

8 Landslides

161

· 161 · 162 · 162 · 166 · 167 · 167 · 169 · 171 · 171 · 171 .172 · 173 · 174 · 175 · 176 · 177

T.p. Gostelow 183 8.1 Introduction . . . . . . . . . . . . . . 183 8.2 Hydrological Triggering Mechanisms . 183 8.3 Rainfall and Landslide Disasters . 185 8.4 Regional Groundwater Flow . . . . . . 187

8.4.1 General ........... . 187 8.4.2 Groundwater in Mountainous Settings . . 188

8.5 First-time and reactivated landslides . 188 8.6 First-time Translational Slides . . . . . . . . . . 188

8.6.1 Examples ............... . 188 8.6.2 Physical Models ofRainfall Infiltration and Mechanisms ofTrans-

lational Failure ........................... 191 8.6.3 First-Time Translational Slides: Rainfall Triggers . . . . . . . . . 193

8.7 First-Time Rotational and Complex Deep-Seated Pre-Existing Landslide Movements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

x Table of Contents

8.7.1 Hydrogeology ofPre-Existing Landslides ............. 195 8.7.2 Mass MovementAssociated with Depression and Perched Springs 196 8.7.3 Geological Susceptibility to Hydrological Landslide Disasters . . 197

8.8 Landslide Caprocks and Their Response to Rainfall . . . . . . . . . . . . 206 8.8.1 General .............................. 206 8.8.2 Landslide and Aquifer Response to Rainfall . . . . . . . . . . . . 206 8.8.3 Spring Discharge from Aquifers and Landslide Caprocks: Moni-

toring a Potential Disaster? ..................... 210 8.8.4 Geological Structure, Aquifers, Valley Sides and Landslides .... 212 8.8.5 Development of Aquifer Properties over Time ........... 216

8.9 Groundwater Models, Pre-Existing Landslide Complexes and Regional Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 8.9.1 Models, Planning and Geographie Information Systems (GIS) ... 216 8.9.2 Recognition and Mapping Groundwater Discharge and Recharge

Areas for Hazard Assessment . . . . . . . . . . . . . . 217 8.10 Landslides Associated with Snowmelt, Permafrost and Glaciers . 218 8.11 Erosion, Rivers and Landslides . . . . . 219 8.12 Storm-Induced Submarine Landslides . 220 8.13 ConcIusions . . . . . . . . . . . . . . 221

9 Land Subsidence G. Gambolati, M. Putti and P. Teatini 231

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 9.2 Review ofMathematical Theory ofLand Subsidence due to Fluid Withdrawal235

9.2.1 Coupled (Biot) Model ofLand Subsidence ............. 236 9.2.2 Uncoupled Model ofLand Subsidence ............... 238 9.2.3 Comparison ofCoupled and Uncoupled Land Subsidence Predictions240

9.3 Illustrative Case Studies .......................... 243 9.3.1 Land Subsidence at Ravenna due to Groundwater Withdrawal ... 243 9.3.2 Land Subsidence in the Ravenna Area Caused by Gas Production . 256 9.3.3 Land Subsidence Prediction at Mexico City ............ 258

10 Saltwater Intrusion M.M. Sherifand v.P. Singh 264

10.1 Hydrological Aspects ............... . 269 10.2 Sharp Interface and Density Dependent Approaches . 270

10.2.1 Sharp Interface Approach . . . . . . . . . . 270 10.2.2 Density Dependent Approach . . . . . . . . 278

10.3 Dispersion in Porous Media . . . . . . . . . . . . . 279 10.3.1 Experimental Investigations on Longitudinal and Lateral Dispersion281 10.3.2 Hydrodynamic Dispersion Equation . . . . . . . . 284

10.4 Mechanism of SaItwater Intrusion into Coastal Aquifers . . 287 10.5 Governing Equations . . . . . . . . . . 287

10.5.1 Sharp Interface Approach . . . 287 10.5.2 Density Dependent Approach . 289

10.6 Initial and Boundary Conditions . 290 10.6.1 Initial Conditions .. . 291 10.6.2 Boundary Conditions . . 291

10.7 Numerical Methods ...... . 295 10.7.1 Finite Difference Method . 295 10.7.2 Finite Element Method. . . 296

10.8 Finite Element Formulation for Density Dependent Problems . 297

Table of Contents

10.9 Study Cases . . . . . . . . 10.9.1 Hypothetical Case . 10.9.2 The Madras Aquifer 10.9.3 The Nile Delta Aquifer in Egypt .

1 O.lOConcluding Remarks . . . . . . . . . . .

11 Avalanche Dynamies K. Hutter

11.1 Introduction . . . . . . . . . 11.1.1 Some Historical Notes 11.1.2 Physical behaviour. . 11.1.3 Laws of Similitude. .

xi

.299

.299

.302

.307

.312

317 . 319 . 319 .320 .323

I. Dynamies of Granular Avalanches 325 11.2 Some Distinctive Characteristics of Granular F10ws . . . . . . . . . . . . 325

11.2.1 Dilatancy, Internal Friction, Rate Dependence of Stress, Large Energy Dissipation . . . . . . . . . . . . 325

11.2.2 Large TravelIed Distances, Size Effects . 327 11.2.3 Three Different F10w Regimes . . 329

11.3 One-Dimensional Model . . . . . . . . . 332 11.3.1 Governing Equations. . . . . . . 332 11.3.2 Comparison with Experiments . . 338 11.3.3 Similarity Solutions . . . . . . 340

11.4 Two-Dimensional Unconfined F10w . . 344 11.4.1 Equations .......... . 344 11.4.2 Experiments and First Results . 346

11. Powder Avalanches 351 11.5 Density and Turbidity Current Concept .............. . 352

11.5.1 Long Gravity or Turbidity Currents . . . . . . . . . . . . . 353 11.5.2 Short gravity currents. "Thermals" on Inclined Boundaries . 363 11.5.3 Other Mixture Models and Critique . . . . 374

11.6 Two-phase F10w Models . . . . . . . . . . . . . . 376 11.6.1 Treatment of Boundary Conditions. . . . . 376 11.6.2 Experimental and Computational Results . 378

11.7 Concluding remarks . . . . . . . . . . . . . . . 386

12 Hydrological Disasters Associated with Volcanoes Y.E. Neall

12.1 Introduction . . . . . . . . . . . 12.2 Steam (Phreatic) Explosions ... 12.3 Eruptions Through a Crater Lake. 12.4 Pyroclastic F10ws Interacting with Water . 12.5 Volcanic Melting of Snow and Ice ... . 12.6 Volcanogenic Tsunamis ........ . 12.7 Release of Gases from a Crater Lake .. . 12.8 Non-Volcanic Initiated Collapse of a Crater Lake 12.9 Heavy Rains on Recently Erupted Materials 12.l0Conclusion ................... .

395 .395 .396 .398 .403 .403 .409 .411 .413 .414 .419

xii

13 Earthquakes A. Terakawa anti O. Matsuo

13.1 Introduetion ..................... . 13.2 Example of Hydrologie Consequenees of Earthquakes .

13.2. J The Zenkouji Earthquake .... . J 3.2.2 The Naganoken Seibu Earthquake . 13.2.3 The Matsushiro Earthquake . . . . 13.2.4 The Izu Oshima Kinkai Earthquake

List of Contributors

Index

Table of Contents

427 .427 .427 .427 .430 .431 .433

435

437

PREFACE

The General Assembly of the United Nations passed a resolution on December 11, 1987, designating the 1990s as the International Decade for Natural Disaster Reduction. This resolution has served as a catalyst in promotion of international cooperation in the field of natural disaster reduction; in initiation of wide-ranging research activities on natural and man-made disasters; in development of tech­nologies for assessment, prediction, prevention, and mitigation through technical assistance, technology transfer, demonstration projects, and education and training; and in dissemination of information related to measures for assessment, prediction, prevention, and mitigation of natural disasters.

Disasters are manifestations of environmental extremes. Depending upon the type of disasters, their occurrence may have short-term andlor long-term detri­mental environmental consequences. Disasters cannot be prevented altogether, but their impact can be mitigated. This book is an attempt to provide a discussion of hydrological aspects of the various types of natural disasters. It is hoped that others will be stimulated to write more comprehensive texts on this subject of enormous importance.

The subject matter of this book is divided into 13 chapters. Abrief perspective of natural disasters is provided in the introductory Chapter 1. Also inc1uded in the chapter are the consequences of these disasters and their mitigation. Representa­tivity of extreme wind data is discussed in Chapter 2. It discusses the concept of representative wind information, c1assification of wind phenomena, requirements for various wind-data users, methods for conforming wind stations with WMO specifications, roughness determination, distribution of average wind speeds, and practical ways to obtain design wind speeds. Climate change and its relation to hydrological disasters constitute the subject matter of Chapter 3. Climate change by itself may not be a disaster but may alter the exposure to hydrological disasters. Therefore, it must be taken into account when planning and designing disaster mitigation schemes.

Floods occur every year throughout the world and cause loss of life and property. Design of ftood-control works is based on statistical methods which are discussed in Chapter 4. Floods are also caused by breaching of dams and cause death and destruction of people and their property in the downstream valley. Such ftoods can be catastrophic. Chapter 5 discusses dam-breach ftoods, with particular attention to breach modeling, ftood routing, and uncertainties associated with dam­breach ftood models. On the other end of the hydrological spectrum are droughts which visit one or the other part of the world virtually every year, causing loss of property and disruption of socio-economic infrastructure. Chapter 6 focuses on the physical processes present in and modeling of droughts.

xiii

xiv Preface

Debris flows occur in many parts of the world, killing people and destroying roadways, bridges, and homes. Such flows are typical in steep, mountainous areas. Chapter 7 reviews the physical processes initiating a debris flow, the models proposed to predict the magnitude and frequency of debris flows, and the mitigation methods. Chapter 8 discusses land slides. Some of the world's worst landslide disasters have been caused by hydrological factors, especially rainfall. Reviewing some of the factors responsible for the distribution ofhydrologically induced slides, the chapter goes on to discuss triggering mechanisms and hydrogeological models, and is concluded with suggestions for identifying and mapping the geological, topographical, and climatic conditions leading to landslides.

Land subsidence is another disaster, caused primarily by over-exploitation of subsurface fluids, such as water, oil, or natural gas. It constitutes the subject matter ofChapter 9. Presenting a summary ofthe most well-known subsiding sites in the world, it goes on to discuss the basic linear theory employed to build mathematical models for prediction of land subsidence due to fluid withdrawal, a comparison of coupled and uncoupled approaches, and three well-known examples of land subsidence due to water and gas extraction. On the other hand, extensive pumping of fresh groundwater and the consequent lowering of the water table or piezometric head causes salt water intrusion in coastal areas, and may degrade the water quality in the aquifer or may even destroy the freshwater resource. Salt water intrusion is the focus of Chapter 10. Presenting the hydrology of salt water intrusion, it discusses the mechanisms, mathematical models, and the initial and boundary conditions, and concludes with a discussion of two case studies.

Avalanche dynamics is the subject of Chapter 11. Introducing the topic with a discussion of some historical notes, physical behavior, and laws of similitude, it provides an extensive review of the dynamics of granular as well as powder avalanches with particular emphasis on their characteristics and modeling. Hydro­logical disasters associated with volcanoes constitute the subject matter of Chapter 12. Volcanoes are triggered by a variety of mechanisms. The chapter reviews each of these mechanisms and emphasizes the need for volcanic monitoring and civil­ian response in order to help reduce the burgeoning number of casualties. The concluding Chapter 13 discusses the hydrological consequences resulting from earthquakes, with examples from Japan.

The editor would like to express his deep gratitude to the chapter contributors who, despite their numerous engagements and hectic schedule, were generous to complete their contributions. He also acknowledges the support and cooperation ofhis wife, Anita, and his children, Vinay and Arti, without which this book would not have come to fruition.

V.P. SINGH Baton Rouge, Louisiana, USA