Climate Change and Water Resources in South Asia - Chapter 1 ppt

Climate Change and
Water Resources in South Asia
Copyright © 2005 Taylor & Francis Group plc, London, UK
Climate Change and Water Resources
in South Asia
Edited by
M. Monirul Qader Mirza
Adaptation and Impacts Research Group (AIRG)
Meteorological Service of Canada, Environment Canada
c/o-Institute for Environmental Studies (IES)
University of Toronto
Canada
Q. K. Ahmad
Bangladesh Unnayan Parishad (BUP)
Niketon, Gulshan-1
Dhaka, Bangladesh
A.A. BALKEMA PUBLISHERS LEIDEN / LONDON / NEW Y ORK / PHILADELPHIA / SINGAPORE
Copyright © 2005 Taylor & Francis Group plc, London, UK
Copyright © 2005 Taylor & Francis Group plc, London, UK
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Published by: A.A. Balkema Publishers, Leiden, The Netherlands,
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Library of Congress Cataloging-in-Publication Data

British Library Cataloguing in Publication Data
ISBN 0 415 36442 6
Printed in Great Britain
Copyright © 2005 Taylor & Francis Group plc, London, UK
In memory of my uncles M. Akramuzzaman, Dr Mirza Muzibul Huq and Dr
M. Ashrafuzzaman.
M. Monirul Qader Mirza
To my sons Rushdy and Urfi and daughter-in-law Farzin.
Q. K. Ahmad
Copyright © 2005 Taylor & Francis Group plc, London, UK
Table of Contents
Foreword R. K. Pachauri xi
Foreword Don MacIver xiii
Preface xv
About the Editors xix
About the Authors xxi
Acronyms xxiii
1
CLIMATE CHANGE AND WATER RESOURCES IN SOUTH ASIA: AN
INTRODUCTION
M. Monirul Qader Mirza
Q. K. Ahmad
1.1 Introduction 1
1.2 Water Availability and Demand in South Asia 2
1.3 Climate Change and Water Resources 8
1.4 Climate Change and Future Water Challenges 8
2
HYDROLOGIC MODELING APPROACHES FOR CLIMATE IMPACT
ASSESSMENT IN SOUTH ASIA
M. Monirul Qader Mirza

2.1 Introduction 23
2.2 Hydrologic Models 23
2.3 Advantages and Limitations of Hydrologic Models in Climate
Change Application 32
2.4 Application of Hydrologic Models for Climate Change Impact
Assessment in Bangladesh 35
2.5 Application of Hydrologic Model in India 45
2.6 Application of Models in Pakistan 46
2.7 Summary and Concluding Remarks 48
Copyright © 2005 Taylor & Francis Group plc, London, UK
3
ARE FLOODS GETTING WORSE IN THE GANGES, BRAHMAPUTRA AND
MEGHNA BASINS?
M. Monirul Qader Mirza
R. A. Warrick
N. J. Ericksen
G. J. Kenny
3.1 Introduction 55
3.2 Hydro-Meteorology of the GBM Basins 57
3.3 The Flood Problem 59
3.4 The Data 63
3.5 Statistical Analyses Methods 65
3.6 Results 65
3.7 Discussion 67
3.8 Conclusions 69
4
CLIMATE CHANGE AND WATER RESOURCES ASSESSMENT IN SOUTH
ASIA: ADDRESSING UNCERTAINTIES
Gary Yohe
Kenneth Strzepek

4.1 Introduction 77
4.2 Defining Uncertainties 78
4.3 Hydro-Climatic Analysis of Flooding in Bangladesh 80
4.4 A Hydrologic Model for the Rivers 83
4.5 Future Climate Scenarios 86
4.6 Assessing Adaptation Under Conditions of Profound Uncertainty 89
4.7 Concluding Remarks 99
5
THE IMPLICATIONS OF CLIMATE CHANGE ON RIVER DISCHARGE IN
BANGLADESH
M. Monirul Qader Mirza
5.1 Introduction 103
5.2 Objectives 107
5.3 Methodology 107
5.4 Estimation of Changes in Annual Discharge 115
5.5 Effects on Mean Peak Discharge 119
5.6 Effects on Depth and Spatial Extent of Flooding 123
5.7 Socio-Economic Effects of Changes in Inundation Categories 131
5.8 Concluding Remarks 132
viii TABLE OF CONTENTS
Copyright © 2005 Taylor & Francis Group plc, London, UK
6
CLIMATE CHANGE AND GLACIER LAKE OUTBURST FLOODS AND THE
ASSOCIATED VULNERABILITY IN NEPAL AND BHUTAN
Motilal Ghimire
6.1 Introduction 137
6.2 GLOF Hydrology 138
6.3 Studies About Glacier Lakes and Their Outburst Events in
Nepal and Bhutan 139
6.4 GLOF Events’ Impact, Vulnerability and Adaptation 144

6.5 Glacier Retreat, GLOF Events and Climate Change 147
6.6 Concluding Remarks 150
7
CLIMATIC CHANGE - IMPLICATIONS FOR INDIA’S WATER RESOURCES
M. Lal
7.1 Background 155
7.2 India’s Geography, Population and Water Needs 156
7.3 Climate of India 160
7.4 Floods and Droughts 171
7.5 Water Resources of India 177
7.6 Future Demand and Supply of Water 188
7.7 Government Policy and Legislative Tools 189
7.8 Coping with Climate Change and Adaptation 190
7.9 Research Needs 193
7.10 Concluding Remarks 193
8
CLIMATE CHANGE AND WATER RESOURCES MANAGEMENT IN
PAKISTAN
Asad Sarwar Qureshi
8.1 Introduction 197
8.2 Water Resources in Pakistan 200
8.3 Major Challenges 207
8.4 Climate Change Impacts on Water Resources: The Way Forward 218
8.5 Concluding Remarks 228
TABLE OF CONTENTS ix
Copyright © 2005 Taylor & Francis Group plc, London, UK
9
CLIMATE CHANGE AND WATER RESOURCES MANAGEMENT IN
BANGLADESH
Hossain Shahid Mozaddad Faruque

Md. Liakath Ali
9.1 Introduction 231
9.2 Water Resources Problems and Their Management 232
9.3 Water Management Practices 237
9.4 Major Studies, Policies and Plans 242
9.5 Climate Change and Water Resources Sector in Bangladesh 244
9.6 Future Framework of Management 246
9.7 Concluding Remarks 252
10
ADAPTATION OPTIONS FOR MANAGING WATER-RELATED EXTREME
EVENTS UNDER CLIMATE CHANGE REGIME: BANGLADESH
PERSPECTIVES
Ahsan Uddin Ahmed
10.1 Introduction 255
10.2 Water-Related Extreme Events and Climate Variability 255
10.3 Climate Change and Its Implications for Water Resources 260
10.4 Coping with Climate Variability 266
10.5 Towards Framework of Future Adaptations 269
10.6 Concluding Remarks 275
11
USING THE ADAPTATION POLICY FRAMEWORK TO ASSESS CLIMATE
RISKS AND RESPONSE MEASURES IN SOUTH ASIA: THE CASE OF
FLOODS AND DROUGHTS IN BANGLADESH AND INDIA
M. Monirul Qader Mirza
Ian Burton
11.1 Introduction 279
11.2 Adaptation Policy Framework 282
11.3 Vulnerability and Adaptation: A Brief Synthesis 284
11.4 Present Vulnerability and Adaptation Measures and Policies
in South Asia: Urban Flooding in Dhaka 287

11.5 Vulnerability of Gujarat to Drought Hazard 296
11.6 Stakeholders’ Participation 299
11.7 Present Adaptation Policies 303
11.8 Future Climate Change, Risks and Adaptation 305
11.9 Adaptation Policy Framework: Opportunities and Challenges 307
11.10 Concluding Remarks 310
xTABLE OF CONTENTS
Copyright © 2005 Taylor & Francis Group plc, London, UK
Foreword
South Asia is home to a population of more than a billion and a quarter. The original
settlers on the subcontinent made this region their home essentially on the attraction of rich
and fertile land and abundant water resources. With rapid growth in the population,
particularly during the last century, the scarcity of water resources has reached an alarming
level, making this a subject deserving of deep attention and an area where major policy
initiatives become essential. Agriculture is still a significant contributor to the GDP of the
countries of South Asia, and well over half the population of the region is dependent on
agriculture or agriculture-related activities. The dominance of the monsoon as a major
source of water supply and the seasonal nature of precipitation in the region, makes the
management of water through irrigation a crucial determinant of agricultural activity. With
industrial growth and urbanization, the demand for water in the industrial sector and in
towns and cities is also increasing rapidly. The problem is compounded by periodic droughts
in certain years and excessive floods particularly during the monsoon season. Both these
phenomena lead to large-scale destruction of infrastructure, property and lives of livestock
and human beings. The problem of climate change is likely to amplify these problems in the
future.
The Third Assessment Report of the IPCC clearly highlights the likelihood of droughts
and floods increasing in the future. The Fourth Assessment Report is likely to shed further
light on this problem, particularly given the fact that water has been included as a
cross-cutting theme for this report. Possible shifts in the onset and adequacy of monsoons,
the retreat of glaciers and changes in magnitude and variability in temperature will

introduce significant changes in water resources availability and uses in South Asia. The
anthology “Climate Change and Water Resources in South Asia” is a timely contribution
to improving knowledge on the impacts of climate variability and changes in water
resources in South Asia and related adaptation measures. The editors and the contributors
are to be congratulated on an important publication.
R. K. Pachauri
Chairman, Intergovernmental Panel
on Climate Change (IPCC),
Geneva, Switzerland
& Director-General, The Energy &
Resources Institute (TERI),
New Delhi, India
Copyright © 2005 Taylor & Francis Group plc, London, UK
Foreword
There is a growing concern across the world about climate variability and change, and
associated vulnerability, impacts and adaptation for various economic sectors. Over the
last decade, the Adaptation and Impacts Research Group (AIRG), Meteorological Service
of Canada, Environment Canada has contributed significantly to the science of
vulnerability, impacts and adaptation (VIA) research nationally and internationally. In
Canada, the AIRG led and contributed to a number of climate change and VIA projects that
include: Canada Country Study; Canadian Climate Impacts Scenarios Project; CCME
Climate Change Indicators Project; Natural Hazards and Disasters in Canada; Climate
Change-Human and Animal Diseases; Climate Change and Water Resources in the Great
Lakes and Climate Change and the Canadian Energy Sector. One of the mandates of the
AIRG is to contribute to international research projects and initiatives in the field of climate
change and VIA research. The AIRG significantly contributed to the Intergovernmental
Panel on Climate Change (IPCC) of the United Nations (UN); the Millennium Ecosystem
Assessment of the UN; the Canada-China Cooperation in Climate Change (C5) Project;
The AIACC AS25 Project, THORPEX-A Global Atmospheric Program and the STARDEX
Project. In addition to East Asia and the Caribbean, South Asia is also becoming an area of

interest of the AIRG in terms of climate change and VIA studies. This anthology is the
third initiative of our international commitment towards South Asia. Previously, Dr. M.
Monirul Mirza edited the anthology “Flood Problem and Management in South Asia”and
“The Ganges Water Diversion: Envronmental Effects and Implications” published by the
Kluwer Academic Publishers, the Netherlands.
South Asia is a region of diverse climates. Livelihood and sustenance of development
are highly climate driven. Floods, droughts and cyclones regularly batter economic
sectors and infrastructure and cause deaths to human and livestock population. Future
changes in the South Asian climates and the sea level rise especially the monsoon, will
have significant impacts on water supply and demand, floods and droughts, changes in
soil moisture, soil degradation, saline water intrusion, pollution of surface and ground
waters and faster melting of the Himalayan glaciers. These changes will have profound
effects on various economic sectors and the livelihoods of millions of people, especially
the poorest section of the South Asian society. In order to reduce vulnerability, there is an
urgent need to design and implement adaptation measures. It is also warranted that
adaptation be integrated into national development plans of the South Asian nations, as a
continuous process. These issues are discussed in the 11 Chapters of this anthology
“Climate Change and Water Resources in South Asia”. It is indeed a significant
contribution from which scientists, vulnerability, adaptation and impact researchers and
Copyright © 2005 Taylor & Francis Group plc, London, UK
policy makers will be benefited. I congratulate the editors, authors, reviewers and
publisher of the anthology for their tremendous hard work in making this noble project a
success.
Don MacIver
Director, Adaptation and Impacts
Research Group (AIRG),
Meteorological Service of Canada,
Environment Canada
xiv FOREWORD
Copyright © 2005 Taylor & Francis Group plc, London, UK

Preface
This anthology presents analyses of research works from five countries of South Asia
who share a number of transboundary river basins. It contains 11 chapters, which address
most of the fundamental issues related to climate variability, climate change and water
resources in South Asia. The journey towards this anthology began six years ago when
we started working with the Third Assessment Report (TAR) of the Intergovernmental
Panel on Climate Change (IPCC) of the United Nations. During the IPCC TAR process, we
felt that there was not enough information readily available on the potential effects of
future climate change on water resources of South Asia. The initiative received a strong
support from Dr. Janjaap Blom, Taylor and Francis Publishers, The Netherlands when the
first editor of this anthology met him during the “International Conference on Water
Resources Management in Arid Regions” in March of 2002 in Kuwait.
In 1992, the UN Framework Convention on Climate Change (UNFCCC) expressed its
concern that the enhanced greenhouse effect due to anthropogenic emission would result
on average in an additional warming of the Earth’s surface and atmosphere and that might
adversely affect natural ecosystems and humankind. A few years later, the
Intergovernmental Panel on Climate Change (IPCC) in its Third Assessment Report
categorically bolstered this concern. The IPCC-TAR released in 2001 stated “…There is
new and stronger evidence that most of the warming observed over the last 50 years is
attributed to human activities”. It further expressed that warming in the last century had
contributed to the observed sea level rise, through thermal expansion of seawater and
widespread loss of sea ice. Evidence of the link between climate change and increasing
climate variability has been mounting rapidly. In a climate change regime, the range of
uncertainty of climate and weather will increase. Overall, the whole climate and hydrologic
system will be impacted. However, there will be regional variations. The implications
of climate variability and change for water resources sector, therefore, warrant updated
information and a complete understanding in order to design and implement adaptation.
Why should climate change be so important for the water sector in South Asia?
Monsoon is an integral part of the hydrologic cycle and water availability in South Asia.
Global Climate Models (GCM) are in general agreement that future climate change will have

a profound impact on monsoon. This will eventually affect availability of water resources
as well as development and investment dynamics. The IPCC-TAR indicates the possibility
of increases in the frequency and intensity of extreme weather events such as floods,
droughts, and heat waves, which are very common in the countries of South Asia.
They often severely affect lives and property, create food insecurity, and accelerate the
process of poverty in many parts of the region. In April of 2004, scientists in the periodical
Nature predicted that a meltdown of the 3 km thick massive Greenland ice sheets due to
global warming would swamp many low-lying areas of the globe that include parts of
South Asia.
Copyright © 2005 Taylor & Francis Group plc, London, UK
There are many difficulties in precisely estimating the impacts of climate change on
water resources. They include physical and climatic characteristics of a river basin, selection
of hydrologic model and scenarios, availability of hydro-meteorological and socio-economic
data and computing and financial resources. Chapters included in this anthology followed
the standard methods for impact assessment established by the IPCC and by many other
regional and sectoral studies.
What will be the potential impacts of climate variability and change on water resources
of South Asia? Large areas in Nepal, India, and Bangladesh are vulnerable to recurrent
floods. In Nepal and Bhutan, Glacier Lake Outburst Floods (GLOFs) are becoming serious
threats to human settlements. Southern provinces of Pakistan and Western India are usually
affected by acute droughts. Loss of human lives, livestock population, and property
are on the rise due to catastrophic natural hazards. Landslides during torrential rains
disrupt communication and supply sediments to dams/reservoirs and river channels.
Floods and droughts also threaten water quality and eventually human health. While in
monsoon there is huge surplus of water in South Asia, the water availability picture in the
dry season is just the opposite. In the dry season, the supply of water cannot simply meet
the demand, which causes intra-country and inter-country water disputes. In a warmer
climate, these problems are expected to exacerbate across South Asia with some degree of
uncertainties.
In a warmer climate in the future, the excess water in monsoon and drought situation

(hydrological, meteorological, and agricultural) in the dry months will cause a number of
water allocation and management problems. Flood management will be a major issue in
Nepal, India, and Bangladesh. Existing flood mitigation/control structures and non-structural
measures will need to be strengthened and tailored to meet the future challenges in a
climate change regime. Drought management will become a much more serious challenge
for India, Pakistan and to a lesser degree for Bangladesh. Irrigation for agriculture remains
by far the largest water consumer in the region. The efficiency of irrigation in the regional
countries is generally low, and many perverse incentives constrain efforts to improve the
situation. Efficiency of irrigation needs to be improved sufficiently to reduce water demand
and structural reforms are required to improve water management. Due to rapid urbanization,
domestic water demand is gradually increasing. With rapid economic and urban
development water, demand will continue to increase. Climate change will act as an additional
factor to the increasing drinking water demand. Water-borne diseases contribute to high
infant mortality in South Asia where access to clean drinking water is limited. In the arid
regions especially of Western India and Southern Pakistan shortages of water supply
become acute during a drought. Regional cooperation on the sharing of water of the
transboundary rivers remains a contentious issue in South Asia. Management of water
quality of the transboundary rivers is another emerging issue, which will need adequate
attention in the future. In recent years, there is encouraging progress in towards organizing
joint responses to the common threat of flooding and other hydrological disasters. Scope
of cooperation will need to be widened and the cooperative framework strengthened for
mutual benefits.
Knowledge on vulnerability and adaptation (VA) can inspire people to mobilize
resources and initiate/strengthen action to lessen the impacts of climate variability and
change. The science of VA has received serious attention in the IPCC process. In recent
years, in terms of global warming, present and future VA activities are given equal
importance. The concept is that the assessment of present vulnerability and adaptation
will help identify the gaps, and addressing them is a step forward towards steeping the
future. In the water sector in South Asia, a variety of adaptation/mitigation measures are
under implementation. However, an adaptation policy framework per se is missing.

xvi PREFACE
Copyright © 2005 Taylor & Francis Group plc, London, UK
A framework is necessary in order adaptation policies can be properly formulated with
reference to different levels of society - national to local levels.
Many reviewers spent a great deal of time in critically reviewing the chapters.
Farzana Abdulhusein patiently and carefully prepared the camera-ready copy. Jane Devie,
Department of Geography University of Toronto drew many maps and graphs. Professor
Marie Sanderson at the Adaptation and Impacts Research Group (AIRG), Environment
Canada reviewed some of the chapters and offered constructive comments. We gratefully
acknowledge all of these contributions. Funding support for preparing the manuscripts
was provided by the AIRG. Our sincere appreciation and thanks to Don MacIver, Director
of the AIRG for his support. We are grateful to the contributors of this book who invested
enormous amounts of time in preparing the chapters. Without their sincere efforts this
book would not have materialized. Finally, the views expressed in this book are those of the
authors and do not reflect the views of their respective organizations.
M. Monirul Qader Mirza
Adaptation and Impacts Research Group (AIRG)
Meteorological Service of Canada, Environment Canada
c/o-Institute for Environmental Studies (IES)
University of Toronto
Canada
Q. K. Ahmad
Bangladesh Unnayan Parishad (BUP)
Niketon, Gulshan-1
Dhaka, Bangladesh
PREFACE xvii
Copyright © 2005 Taylor & Francis Group plc, London, UK
About the Editors
Dr M. Monirul Qader Mirza has extensively researched on hydrological and climate
extremes, natural hazards and their management, climate change and water resources and

associated vulnerability, impact and adaptation and environmental impacts of water
diversions from the transboundary rivers. He received his PhD from the International
Global Change Institute (IGCI), University of Waikato, Hamilton, New Zealand on climate
change and flooding in Bangladesh in 1998. He contributed as a Coordinating Lead Author
(CLA) to the Special Regional Report and the Third Assessment Report (TAR) of the
Intergovernmental Panel on Climate Change (IPCC) of the United Nations and to the
Millennium Ecosystem Assessment. Presently he is contributing as a CLA to the IPCC’s
Fourth Assessment Report, Working Group II. He is currently with the Adaptation and
Impacts Research Group (AIRG), Meteorological Service of Canada, Environment Canada.
He is also an Adjunct Professor at the Institute for Environmental Studies (IES), University
of Toronto, Canada. He has been declared as a Burtoni Fellow of the Meteorological
Service of Canada for the year 2004-2005. He has recently been appointed as the Editor of
“Adaptation Science”, a quarterly Newsletter of the AIRG. He is a member of the American
Society of Civil Engineers and Professional Engineers, Ontario, Canada.
Dr Q. K. Ahmad is a socio-economic specialist of international repute and has to his credit
a wide range of research work on environment and water resources, climate change, policy
planning, food and agriculture, rural development, poverty alleviation, human
development, technology and employment generation, women in development and
gender issues. He extensively studied various issues related to water resources
development and cooperation in the South Asia Region. He received his PhD from the
London School of Economics and Political Science, London University in 1976. He is
Chairman and Chief Executive, Bangladesh Unnayan Parishad (BUP), Dhaka. He was the
President and International Vice-President of the Association of Development Research
and Training Institutes of Asia and the Pacific (ADIPA), Kuala Lumpur and Society for
International Development (SID), Rome, respectively. During 1998-2001, he acted as a
Coordinating Lead Author to the IPCC’s Third Assessment Report. Presently he is
contributing as a Lead Author to the IPCC’s Fourth Assessment Report, Working Group II.
Copyright © 2005 Taylor & Francis Group plc, London, UK
About the Authors
Ahsan Uddin Ahmed is the Director, Bangladesh Unnayan Parishad (BUP)-Centre for

Water and Environment, Niketon, Gulshan-1, Dhaka, Bangladesh. His research focuses on
climate change, vulnerability, impacts and adaptation; regional cooperation in water
sharing; environment and resource management for sustainable development.
Asad Sarwar Qureshi is presently Head of International Water Management Institute
(IWMI) office in Iran where he is focusing on increasing water productivity of dry and
marginal lands. He has long been associated with the adaptive research aimed at irrigation
management to increase land and water productivity especially in the Indus basin. He has
special interests in integrated water management modeling to evaluate the impacts of
different water management strategies on crop production and environment.
Gary Yohe is the John E. Andrus Professor of Economics at Wesleyan University,
Connecticut, USA. He has been working in the climate area for more than 20 years, with
specific focus on coping with the sources and implications of the profound uncertainty
that clouds our view of how the future will unfold.
Gavin J. Kenney is presently working as an independent climate and agriculture
consultant in New Zealand. He was previously with the International Global Change
Institute (IGCI), University of Waikato, Hamilton, New Zealand and the Environmental
Change Unit, University of Oxford, U.K.
Hossain Shahid Mozaddad Faruque is currently the Director General, Water Resources
Planning Organization (WARPO), Ministry of Water Resources, Government of Bangladesh.
Trained as a water resources engineer, he has been associated with the planning of
Bangladesh’s water sector for over three decades.
Ian Burton is an Emeritus Professor, Department of Geography and Planning and Institute
for Environmental Studies (IES), University of Toronto, Canada. He is also a Scientist
Emeritus with the Adaptation and Impacts Research Group (AIRG), Meteorological
Service of Canada, Environment Canada. He is currently the President of the International
Society of Biometeorology.
Kenneth Strzepek is a Professor in the Civil, Environmental and Architectural Engineering
Department at the University of Colorado, Boulder, USA. His areas of expertise include
modeling of river basins with a focus on the implications of climate change and socio-
economic development across the associated watersheds.

Copyright © 2005 Taylor & Francis Group plc, London, UK
M. Lal is currently with the Pacific Centre for Environment and Sustainable Development,
University of South Pacific, Suva, Fiji as a Visiting Professor. His research interests
include: global and regional climate, modeling the climate and its variability, regional
environmental change-integrated approach, vulnerability assessment and regional
adaptation and mitigation potentials. He is a Coordinating Lead Author of the
Intergovernmental Panel on Climate Change (IPCC) of the United Nations, Fourth
Assessment Report, Working Group II.
M. Monirul Qader Mirza
is currently with the Adaptation and Impacts Research Group
(AIRG), Meteorological Service of Canada, Environment Canada. He is also an Adjunct
Professor, Institute for Environmental Studies (IES), University of Toronto, Canada. His
research mainly focuses on extreme hydro-meteorological events, hydrologic modeling,
climate change and associated vulnerability, impact and adaptation.
Md. Liakath Ali, Senior National Expert, Program Development Office for Integrated Coastal
Zone Management Plan (ICZMP), Water Resources Planning Organization (WARPO),
Ministry of Water Resources, Government of Bangladesh.
Motilal Ghimire is at the Central Department of Geography, Tribuvan University,
Kathmandu, Nepal. Areas of his research interest include: socio-economic conditions of
the mountains, mountain hydrology and water resources, extreme hydrological events and
application of geographic information system (GIS) in vulnerability assessment.
Neil Ericksen is the founding Director of the International Global Change Institute (IGCI),
University of Waikato, Hamilton, New Zealand. His research interests are: human response
to natural hazards and climate change, governance and environmental management, and
resource planning.
Q. K. Ahmad is the Chairman of the multidisciplinary research organization Bangladesh
Unnayan Parishad (BUP); and President, Bangladesh Economic Association (BEA), Dhaka,
Bangladesh. He has to his credit a wide range of research works and publications,
including on environment and water resources, regional cooperation, climate change, policy
planning, food and agriculture, rural development, poverty alleviation, human

development, technology, employment generation, and gender issues.
Richard Warrick is the Deputy Director of the International Global Change Institute
(IGCI), University of Waikato, Hamilton, New Zealand. His recent research activities have
focused on climate related issues, particularly global climate and sea level changes and on
the development of integrated models for assessing the effects of climate change and
variability at national and regional scales.
xxii ABOUT THE A UTHORS
Copyright © 2005 Taylor & Francis Group plc, London, UK
Acronyms
ADB Asian Development Bank
ADRC Asian Disaster Reduction Center
BCM Billion Cubic Meter
BDCLIM Bangladesh Climate Model
BOD Bio-chemical Oxygen Demand
BWDB Bangladesh Water Development Board
CCC Canadian Climate Centre
CCIRG Climate Change Impact Review Group
CCCma Canadian Centre for Climate Modeling and Analysis
CDBI Climate Diagnostic Board of India
COLA Center for Ocean Land and Atmosphere
CPCB Central Pollution Control Board
CSE Centre for Science and Environment
CSIRO Commonwealth Scientific Industrial Research Organization
CWC Central Water Commission
DHM Department of Hydrology and Meteorology
EANHMP East Asia Natural Hazard Management Project
ENSO El Niño Southern Oscillation
EPADC East Pakistan Agriculture Development Corporation
EPWAPDA East Pakistan Water and Power Development Authority
FANA Federally Administered Northern Areas

FAO Food and Agriculture Organization of the United Nations
FAP Flood Action Plan
FCD Flood Control and Drainage
FCDI Flood Control Drainage and Irrigation
FEC French Engineering Consortium
FPCO Flood Plan Coordination Organization
GBM Ganges, Brahmaputra and Meghna
GCM Global Climate Model
GDP Gross Domestic Product
GFDL Geophysical Fluid Dynamics Laboratory
GLOF Glacier Lake Outburst Flood
GoB Government of Bangladesh
GoI Government of India
GoP Government of Pakistan
GPP Guidelines for Peoples Participation
GSI Geological Survey of India
HBV Hydrologiska Byrans Vattenbalansavdelning
Copyright © 2005 Taylor & Francis Group plc, London, UK
HEC Hydrologic Engineering Center
HYVs High Yielding Varieties
IBRD International Bank for Reconstruction and Development
ICIMOD International Centre for Integrated Mountain Development
IMD India Meteorological Department
IPCC Intergovernmental Panel on Climate Change
IRMB Institute of Royal Meteorology Belgium
ITCZ Inter-Tropical Convergence Zone
IWMI International Water Management Institute
JICA Japan International Cooperation Agency
LLNL Lawrence Livermore National Laboratory
MAGICC Model for the Assessment of Greenhouse Gas Induced Climate Change

MODSIM Model Simulation
MOE Ministry of Environment
MPO Master Plan Organization
MSL Mean Sea Level
MWR Ministry of Water Resources
NERC National Environment Research Council
NIO National Institute of Oceanography
NWCF Nepal Water Conservation Foundation
NWFP Northwest Frontier Province
NWMP National Water Management Plan
OECD Organization for Economic Cooperation and Development
PET Potential Evapo-Transpiration
RAJUK Rajdhani Unnayan Katripakha
SAARC South Asian Association for Regional Cooperation
SCENGEN Scenario Generator
SLR Sea Level Rise
SRES Special Report on Emission Scenarios
SWAT Soil and Water Assessment Tool
TDS Total Dissolved Solids
UBC University of British Columbia
UKMOH United Kingdom Meteorological Office High Resolution Model
UKTR United Kingdom Meteorological Transient Model
UNDP United Nations Development Programme
UNEP United Nations Environment Programme
UNESCO United Nations Educational Scientific and Cultural Organization
UNFCCC United Nations Framework Convention on Climate Change
UNICEF United Nations International Children’s Emergency Fund
USEPA United States Environment Protection Agency
WARPO Water Resources Planning Organization
WAPDA Water and Power Development Authority

WECS Water and Energy Commission Secretariat
WMO World Meteorological Organization
WRDTC Water Resources Development and Training Centre
xxiv ACRONYMS
Copyright © 2005 Taylor & Francis Group plc, London, UK
1
Climate Change and Water Resources in South
Asia: An Introduction
M. MONIRUL QADER MIRZA
Q. K. AHMAD
1.1 INTRODUCTION
The South Asia region contains many large river systems: Ganges, Brahmaputra, Meghna,
Indus, Godavari, Mahanadi, and Narmada (Fig. 1.1), which support millions of people. The
river systems of South Asia can be classified into four major groups (a) Himalayan rivers;
(b) Deccan rivers; (c) Coastal rivers; and (d) Rivers of the inland drainage basin. Table 1.1
lists these major rivers of South Asia, their origins and sources of water. The Himalayan
rivers are formed by melting snow and glaciers and have continuous flow throughout the
year. Snow and rainfed river basins occupy 2.32 million km
2
or 55% of basin areas while the
remaining 1.90 million km
2
or 45% of basin areas belong to rainfed rivers. Snow and glaciers
are partial sources of water for the large rivers: the Ganges, Brahmaputra and Indus, which
originate in the Himalayas (Fig. 1.1). The rivers of the Deccan plateau are rainfed and
fluctuate in volume, many of them being non-perennial; the coastal rivers, which,especially
on the West Coast, are short in length with small catchment areas, most of them being
non-perennial; and the rivers of the inland drainage basin in Western Rajasthan, which are
ephemeral, drain towards the silt lakes such as Sambhar, or are lost in the desert sands.
Water availability in this region is driven by monsoons, which are cyclical wave-like

air masses that occur in the sub-tropics, moving from the sea to land during the summer
and land to water in winter. The word monsoon comes from the Arabic mausim, meaning
‘season,’ because these storms return every year. Two monsoon systems operate in the
region: the Southwest or summer monsoon and the Northeast or winter monsoon (Box 1.1
and Fig. 1.2). The summer monsoon accounts for 70%-90% of the annual rainfall over most
of South Asia, except over Sri Lanka and Maldives where the Northeast monsoon is
dominant. Apart from the monsoon, the Northern part of South Asia receives considerable
precipitation from Western disturbances, and in the Southern parts (especially Sri Lanka),
from weather associated with the ITCZ (Inter-Tropical Convergence Zone). Considerable
monsoon variability occurs in both space and time. There is also a clear association between
El Niño events and weak monsoons. During the period 1871-2001, 11 of 22 drought years
were El Niño years (Kumar et al., 2003). Between 1901 and 1990, rainfall was deficient in all
seven strong El Niño cases.
Copyright © 2005 Taylor & Francis Group plc, London, UK
Fig. 1.1 South Asia region and major rivers. Source: Ben Crow et al., 1995. Reproduced with
permission.
1.2 WATER AVAILABILITY AND DEMAND IN SOUTH ASIA
Per capita/year water availability in South Asia is shown Table 1.2. It demonstrates two
issues. There is a sharp contrast among the South Asian nations in terms of water
availability and consumption, and all countries have surplus water. The figures, however,
mask serious imbalances. They do not reveal the wide variability in time and space (Subba,
2001). Most of these waters are generated in the monsoon (June-September) and flow
unused to the sea. Figure 1.3 shows seasonal availability of water for some South Asian
rivers. For some selected rivers the ratios of dry season and monsoon flows are: 1:6
(Ganges), 1:4 (Brahmaputra), 1:12 (Narmada) and 1:10 (Godavari).
Water scarcity is a serious problem in Pakistan. Several parts of India are water stressed
which include the regions in the Indus, Krishna and Ganges sub-basins. Regions with East
flowing rivers between Mahanadi and Pennar, and West flowing rivers of Kach and
Kathiawar experience water scarcity, while the regions with East flowing rivers between
Pennar and Kanyakumari suffer with absolute water scarcity (per capita availability

14 m
3
/year). Even during the monsoon, a large area in India and Bangladesh suffers from
water scarcity and sometimes from drought.
2CLIMATE CHANGE AND WATER RESOURCES IN SOUTH ASIA
Copyright © 2005 Taylor & Francis Group plc, London, UK
Table 1.1 Salient physical features of major
rivers
of South Asia
River
Indus
Ganges
Brahmaputra
Meghna/Barak
Sabarmati
Mahi
Narmada
Tapi
Mahanadi
Godavari
Krishna
Pennar
Cauvery
Origin
Manasorovar (Tibet)
Gangotri (Uttar Khashi)
Kailash Range (Tibet)
North of Manipur Hills
(India)
Aravalli Hills (Rajasthan)

Dhar (Madhya Pradesh))
Amarkantak
(Madhya Pradesh))
Betul (Madhya Pradesh)
Nazri Town (Madhya
Pradesh)
Nasik (Maharashtra)
Mahabaleshwar (Maharashtra)
Kolar (Karnataka)
Coorg (Karnataka)
Length
(km)
2,880
2,525
2,900
900
371
583
1,312
724
851
1,465
1,401
597
800
Source of Water
Snow Rainfall
• •
• •
• •

•
•
•
•
•
•
•
•
•
•
Basin Area
(10
6
sq. km)
0.47
1.086
0.58
0.078
0.021
0.034
0.098
0.065
0.14
0.31
0.29
0.055
0.81
Source: Modified from
Central Water
Commission,

1987.
M. M. Q. MIRZA AND Q. K. AHMAD 3
Copyright © 2005 Taylor & Francis Group plc, London, UK
Box 1.1 Summer and Winter Monsoons
All monsoons share three basic physical mechanisms: differential heating between
the land and oceans; Coriolis forces due to the rotation of
the
earth; and the role of
water which stores and releases energy as it changes from liquid to vapor and
back (latent heat). During the summer, incoming radiation is absorbed by the
Tibetan plateau, heating the air above it and causing it to rise. Low-level warm air
also flows Southward from the Arabian Peninsula, the African Sahel desert,
Rajasthan, and Pakistan. The Westerly jet stream over Northern India shifts North
of the Himalayas. The Westerly jet stream in South India changes direction and
becomes Easterly. The Somali jet stream crosses into the Arabian Sea, changing
the direction of ocean currents. Colder water welling up from lower ocean layers
lowers the temperature. A low-pressure trough where the Southern and Northern
trade winds meet, a border known as the inter-tropical convergence zone (ITCZ),
moves North. In the case of Indian summer monsoon, the first and third
mechanisms produce more intense effects than any other place in the world.
There is also a winter monsoon (Northeast monsoon), created during the
winter when the sun's rays are stronger in the Southern Hemisphere. During this
season, the continents are cooler than the water, which retains absorbed heat. The
air reverses circulation, with warm air rising over the oceans and cooler land air,
called 'cold surges', rushing in to replace it. The cold surges pick warm moisture
as they travel across tropical waters, and release it over Indonesia, Northern
Australia, Sri Lanka, and the East Indian Coast.
Source: McCurry, 1988.
Fig. 1.2 Monsoons and directions of air movement.
It is estimated that up to 80% of the water supply of dry season flow of the Indus,

Ganges and Brahmaputra Rivers comes from Himalayan glaciers (Table 1.3) (Subba, 2001).
This estimate seems to be high. On an annual basis, for the Ganges and Brahmaputra, the
contribution of snow and glaciers is insignificant which is <1% (Mirza, 1997). At the high
end, it has been estimated that snow and glacier melt contributes roughly 10% of the total
flow generated in the Nepalese rivers (Sharma, 1977; Gyawali, 1989). Since the Western
Himalayas receives less monsoon rain but higher winter snowfall than the Central and
4CLIMATE CHANGE AND WATER RESOURCES IN SOUTH ASIA
Copyright © 2005 Taylor & Francis Group plc, London, UK
Eastern Himalayas, the dependence of the Indus on ice melt from glaciers is greater than
that of the Ganges and Brahmaputra. The Chenab, one of the five tributaries of the Indus,
is almost completely glacier-fed.
Water demand is generally created by three driving forces: increases in population,
agriculture, and industrial growth. In future, climate change may act as an added factor by
altering water supplies. Each of these factors will be considered below.
1.2.1 POPULATION GROWTH
South Asia is one of the most densely populated regions of the world. The current (2001)
population is estimated to be 1,220 million. The ratio of rural and urban population is
roughly 3:1 (UN, 1994). Population growth has both direct and indirect effects on water
demand (Fig. 1.4). The main direct effect is an increased need of water for domestic
purposes (including recreation). Increases in water use could be affected by a number of
factors, such as increases in per capita income and rural to urban migration. Generally,
economically affluent people use more water. For example, Dhaka’s urban dwellers living
in the high income residential areas use 2.5 times more water than these with average
incomes. As well, the per capita standard urban water requirement is considered to be
2 times higher than that of rural areas. Overall, there is no doubt that increases in
population will create larger water demand. However, there are other factors, which may
play a significant role in determining water use patterns. They are: pattern of urbanization,
the degree of adoption of water-conservation technology, and institutional factors
governing directly or indirectly the degree of demand management (Kulshrestha, 1993).
One additional factor, the pricing of water, is an important determinant in future water use

and demand. Currently, in South Asia, water is highly subsidized which encourages
inefficient water use, thereby creating more demand.
1.2.2 AGRICULTURE
At present, agriculture is the single largest contributor to the GDP of South Asian
countries. The highest and the lowest contribution of the agriculture sector is 41% and
20% for Nepal and Sri Lanka, respectively (ADB, 2003). In future, agriculture will likely
remain an important sector of the economy in terms of food production as well as
employment generation. Water requirements for the agriculture sector are also the highest
in South Asia.
Future water demand in the agriculture sector will also be driven indirectly by
M. M. Q. MIRZA AND Q. K. AHMAD 5
Copyright © 2005 Taylor & Francis Group plc, London, UK
increases in population through: the demand for food (cereals and corns), and the demand
for non-food (industrial) and farm products. The increased demand for food may be met by
taking one or more of the following measures suggested by Kulshrestha (1993): expanding
the rainfed (dry land) area, improving the productivity of the rainfed (dry land) area,
expanding the irrigated area, improving the productivity of irrigated agriculture, and
importing food from other countries. The last measure will not create water demand in the
food-importing region. In South Asia, there is very limited scope for the expansion of
rainfed agricultural land because most of the land is already under cultivation. There may
be some scope for increasing the productivity of rainfed land, but currently that is
constrained by floods, droughts, temporary inundation from rainfalls, tidal flows and coastal
salinity (Hossain and Fisher, 1995). Note that in South Asia yields of rice under rainfed
conditions compared with those of irrigated rice yields are low. Therefore, it is assumed
that increased demand for food will be met by expanding the area under irrigation. This will
have a substantial impact on future water demand.
Fig. 1.3 Mean monthly discharge of the Ganges, Brahmaputra, Godavari and Narmada Rivers. Data
source: Bangladesh Water Development Board (BWDB) and Global Runoff Data Center, Germany.
Poultry and livestock products constitute a portion of the food intake in South Asia.
India has the largest bovine population in the world and milk is an important drink in India

and other countries. It is assumed that the dietary habits of people have been changing
recently which people consuming more meat now than before. This is perhaps due not
only to the increases in income levels but also decreased per capita availability of fish.
The intake of milk and milk products (cheese, butter, clarified butter, yogurt, ice cream, etc.)
is increasing and becoming popular in many South Asian countries. Therefore, in future,
increases in demand for poultry and livestock products will be translated into an increased
number of livestock. This would result in increased water demand for stock watering,
growing forages and livestock feeds (Kulshrestha, 1993).
0
10000
20000
30000
40000
50000
60000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Discharge (m3/sec)
Ganges
Brahmaputra
Godavari
Narmada
6CLIMATE CHANGE AND WATER RESOURCES IN SOUTH ASIA
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