Handbook of Drought and Water Scarcity: Environmental Impacts and Analysis of Drought and Water Scarcity [1 ed.] 149873104X, 9781498731041

This volume includes over 30 chapters, written by experts from around the world. It examines the environmental aspects o

609 79 32MB

English Pages 703 [705] Year 2017

Report DMCA / Copyright

DOWNLOAD FILE

Polecaj historie

Handbook of Drought and Water Scarcity: Environmental Impacts and Analysis of Drought and Water Scarcity [1 ed.]
 149873104X, 9781498731041

Citation preview

Handbook of Drought and Water Scarcity

Environmental Impacts and Analysis of Drought and Water Scarcity

Handbook of Drought and Water Scarcity

Environmental Impacts and Analysis of Drought and Water Scarcity

Edited by

Saeid Eslamian and Faezeh Eslamian

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2016 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-4987-3104-1 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright. com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging‑in‑Publication Data Names: Eslamian, Saeid, editor. | Eslamian, Faezeh A., editor. Title: Handbook of drought and water scarcity : environmental impacts and analysis of drought and water / edited by Saeid Eslamian and Faezeh A. Eslamian. Description: New York : CRC Press, 2017Identifiers: LCCN 2016030589| ISBN 9781498731089 (v. 1 : hardback) | ISBN 9781315404226 (v. 1 : e-book) Subjects: LCSH: Droughts. | Drought forecasting. | Water-supply. | Environmental impact analysis. Classification: LCC QC929.24 .H36 2017 | DDC 551.57/73--dc23 LC record available at https://lccn.loc.gov/2016030589 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Contents Editors����������������������������������������������������������������������������������������������������������������������� ix Contributors������������������������������������������������������������������������������������������������������������� xi

1 Drought Vulnerability.........................................................................................1 Chandrashekhar Bhuiyan

2

Drought Impacts on Urbanization....................................................................17

3

Environmental Impacts of Drought on Desertification Classification........... 45

Shafi Noor Islam and Samina Mazumder Tuli Nicolas R. Dalezios and Saeid Eslamian

4

Climate Parameter Variability. . ........................................................................ 65

5

Climate Change Impact on Urban Water Deficit.. ............................................81

6

Climate Change Impacts on and Adaptation to Groundwater.......................107

7

Climate Change Impacts on Precipitation and Temperature......................... 125

8

Minimizing the Impacts of Drought............................................................... 143

9

Climate Change and Drought: Building Resilience for an Unpredictable Future . . ............................................................................................................. 163

Marco Casazza

Sara Nazif, Hamed Tavakolifar, and Saeid Eslamian

Shamsuddin Shahid, Mahiuddin Alamgir, Xiao-jun Wang, and Saeid Eslamian Marina Baldi

Oluwagbenga O.I. Orimoogunje and Saeid Eslamian

Hamideh Maleksaeidi, Marzieh Keshavarz, Ezatollah Karami, and Saeid Eslamian

1 0

Sustainable Agriculture: Building Social-Ecological Resilience.................... 187

11

Drought and Water Quality . . .......................................................................... 205

1 2

Securing Water Pollution................................................................................ 219

Mohammad Naser Reyhani, Saeid Eslamian, and Alireza Davari Theodore C. Crusberg and Saeid Eslamian Marine Nalbandyan

v

vi

Contents

13

Conjunctive Use of Water Reuse in Drought. . ............................................... 243

1 4

Criteria for Wastewater Treatment and Reuse under Water Scarcity........... 263

15

Drought and Groundwater Quality in Coastal Areas. . .................................. 283

1 6

Contamination of Groundwater in Arid and Semiarid Lands....................... 291

1 7

Sanitation in Drought.. .................................................................................... 315

1 8

Environmental Flows Assessment in Scarce Water Resources....................... 331

1 9

Low Flow and Instream Flow Requirements..................................................353

2 0

Streamflow Quality in Low-Flow Conditions. . ...............................................375

2 1

River Sediment in Low Flow Condition........................................................ 387

2 2

Impact of Overexploitation of Water Resources on Ecohydrological Change in China. . ........................................................................................... 409

Katherine Y. Bell, Robert Bastian, and Jennifer A. Gelmini

Miquel Salgot, Gideon Oron, Giuseppe L. Cirelli, Nicolas R. Dalezios, Amelia Díaz, and Andreas N. Angelakis Yohannes Yihdego

Noureddine Gaaloul, Saeid Eslamian, and Benoit Laignel Bosun Banjoko and Saeid Eslamian

Alireza Davari, Ali Bagheri, Mohammad Naser Reyhani, and Saeid Eslamian Salvatore Alecci and Giuseppe Rossi Qin Qian and Saeid Eslamian

Nazanin Mohammadzade Miyab, Saeid Eslamian, and Nicolas R. Dalezios

Tadanobu Nakayama

2 3

Crop Insurance in Drought Conditions. . ....................................................... 423

2 4

Biotechnology for Drought Improvement..................................................... 445

2 5

Water Issues from a System Dynamics Perspective........................................461

2 6

Rainwater Harvesting in Arid Regions of Australia...................................... 489

2 7

Water Conservation Techniques.....................................................................501

2 8

Food Security and Nutrition Policy................................................................ 521

2 9

C. Dionisio Pérez-Blanco, Gonzalo Delacámara, C. Mario Gómez, and Saeid Eslamian

Danial Kahrizi, Kasra Esfehani, Ali Ashraf Mehrabi, Matin Ghaheri, Zahra Azizi Aram, Solmaz Khosravi, and Saeid Eslamian Peter Wade and Saeid Eslamian

Ataur Rahman, Evan Hajani, and Saeid Eslamian

Meysam Malekian Jabali, Saeid Okhravi, Saeid Eslamian, and Saeed Gohari Shafi Noor Islam, Sandra Reinstädtler, Maria Aparecida de SáXavier, and Albrecht Gnauck

Soil Contaminations in Arid and Semiarid Land.......................................... 547

Saumitra Mukherjee, Kamana Yadav, and Saeid Eslamian

Contents

vii

3 0

Water Scarcity and Sustainable Urban Green Landscape.............................. 557

31

Drought in Lake Urmia.................................................................................. 605

3 2

Interbasin Transfers of Water: Zayandeh-Rud River Basin. . ..........................619

3 3

Environmental Evaluation: Lessons Learned from Case Studies................... 631

3 4

Paleo-Drought: Measurements and Analysis. . ............................................... 665

Soleyman Dayani, Mohammad R. Sabzalian, Mahdi Hadipour, and Saeid Eslamian Saeid Okhravi, Saeid Eslamian, and Saleh Tarkesh Esfahany

Alireza Gohari, Mohammad Javad Zareian, Saeid Eslamian, and Rouzbeh Nazari Bosun Banjoko and Saeid Eslamian

Dinara Abbasova, Saeid Eslamian, and Rouzbeh Nazari

Index. . ..................................................................................................................... 675

Editors Saeid Eslamian is a full professor of hydrology and water resources engineering in the Department of Water Engineering at Isfahan University of Technology, where he has been since 1995. His research focuses mainly on statistical and environmental hydrology in a changing climate. In recent years, he has worked on modeling natural hazards, including floods, severe storms, wind, drought, pollution, water reuses, sustainable development and resiliency, etc. Formerly, he was a visiting professor at Princeton University, New Jersey, and the University of ETH Zurich, Switzerland. On the research side, he started a research partnership in 2014 with McGill University, Canada. He has contributed to more than 500 publications in journals, books, and technical reports. He is the founder and chief editor of both the International Journal of Hydrology Science and Technology (IJHST) and the Journal of Flood Engineering (JFE). Eslamian is now associate editor of three important publications: Journal of Hydrology (Elsevier), Eco-Hydrology and Hydrobiology (Elsevier), and Journal of Water Reuse and Desalination (IWA). Professor Eslamian is the author of approximately 150 book chapters and books. Dr. Eslamian’s professional experience includes membership on editorial boards, and he is a reviewer of approximately 50 Web of Science (ISI) journals, including the ASCE Journal of Hydrologic Engineering, ASCE Journal of Water Resources Planning and Management, ASCE Journal of Irrigation and Drainage Engineering, Advances in Water Resources, Groundwater, Hydrological Processes, Hydrological Sciences Journal, Global Planetary Changes, Water Resources Management, Water Science and Technology, EcoHydrology, Journal of American Water Resources Association, American Water Works Association Journal, etc. UNESCO has also nominated him for a special issue of the Eco-Hydrology and Hydrobiology Journal in 2015. Professor Eslamian was selected as an outstanding reviewer for the Journal of Hydrologic Engineering in 2009 and received the EWRI/ASCE Visiting International Fellowship in Rhode Island (2010). He was also awarded outstanding prizes from the Iranian Hydraulics Association in 2005 and Iranian Petroleum and Oil Industry in 2011. Professor Eslamian has been chosen as a distinguished researcher of Isfahan University of Technology (IUT) and Isfahan Province in 2012 and 2014, respectively. In 2016, he was a candidate for national distinguished researcher in Iran. He has also been the referee of many international organizations and universities. Some examples include the U.S. Civilian Research and Development Foundation (USCRDF), the Swiss Network for International Studies, the Majesty Research Trust Fund of Sultan Qaboos University of Oman, the Royal Jordanian Geography Center College, and the Research Department of Swinburne University of Technology of Australia. He is also a member of the following associations: American Society of Civil Engineers (ASCE), International Association of Hydrologic Science (IAHS), World Conservation Union ix

x

Editors

(IUCN), GC Network for Drylands Research and Development (NDRD), International Association for Urban Climate (IAUC), International Society for Agricultural Meteorology (ISAM), Association of Water and Environment Modeling (AWEM), International Hydrological Association (STAHS), and UK Drought National Center (UKDNC). Professor Eslamian finished Hakimsanaei High School in Isfahan in 1979. After the Islamic Revolution, he was admitted to IUT for a BS in water engineering and graduated in 1986. After graduation, he was offered a scholarship for a master’s degree program at Tarbiat Modares University, Tehran. He finished his studies in hydrology and water resources engineering in 1989. In 1991, he was awarded a scholarship for a PhD in civil engineering at the University of New South Wales, Australia. His supervisor was Professor David H. Pilgrim, who encouraged him to work on “Regional Flood Frequency Analysis Using a New Region of Influence Approach.” He earned a PhD in 1995 and returned to his home country and IUT. In 2001, he was promoted to associate professor and in 2014 to full professor. For the past 22 years, he has been nominated for different positions at IUT, including university president consultant, faculty deputy of education, and head of department. Professor Eslamian has made three scientific visits to the United States, Switzerland, and Canada in 2006, 2008, and 2015, respectively. In the first, he was offered the position of visiting professor by Princeton University and worked jointly with Professor Eric F. Wood at the School of Engineering and Applied Sciences for one year. The outcome was a contribution in hydrological and agricultural drought interaction knowledge by developing multivariate L-moments between soil moisture and low flows for northeastern U.S. streams. Recently, Professor Eslamian has completed the editorship of eight handbooks published by Taylor & Francis (CRC Press): the three-volume Handbook of Engineering Hydrology in 2014, Urban Water Reuse Handbook in 2015, Underground Aqueducts Handbook (2016), the three-volume Handbook of Drought and Water Scarcity (2017). Faezeh Eslamian is a PhD candidate of bioresource ­ engineering and research assistant at McGill University, Montreal, Quebec, Canada. She is currently working on the fate and transport of ­phosphorus through subsurface drained farmlands. Dr. Eslamian completed her bachelor’s and master’s degrees in civil and environmental engineering from Isfahan University of Technology, Iran, where she evaluated natural and low-cost absorbents for the removal of pollutants such as textile dyes and heavy metals. Furthermore, she has conducted research on the worldwide water quality standards, wastewater reuse, and drought guidelines.

Contributors Dinara Abbasova Institute of Radiation Problem Institute of Radiation Problems of AzNAS Baku, Azerbaijan and Institute of Geology of PAN Warsaw, Poland Mahiuddin Alamgir Department of Civil Engineering Universiti Teknologi Malaysia Johor, Malaysia Salvatore Alecci Department of Civil and Environmental Engineering Italian Hydrotechnical Association Catania, Italy Andreas N. Angelakis Institute of Iraklion National Foundation for Agricultural Research Hellas, Greece Zahra Azizi Aram Department of Agronomy and Plant Breeding Razi University Kermanshah, Iran

Bosun Banjoko Department of Chemical Pathology and Institute of Public Health College of Health Sciences Obafemi Awolowo University Ile-Ife, Nigeria Robert Bastian Office of Wastewater Management U.S. Environmental Protection Agency Washington, DC Katherine Y. Bell Department of Civil and Environment Engineering MWH Global Nashville, Tennessee Chandrashekhar Bhuiyan Department of Civil Engineering Sikkim Manipal Institute of Technology Rangpo, Sikkim, India Marco Casazza Department of Sciences and Technologies Parthenope University of Napoli Napoli, Italy

Ali Bagheri Department of Water Engineering Tarbiat Modares University Tehran, Iran

Giuseppe L. Cirelli Department of Agriculture, Food, and Environment University of Catania Catania, Italy

Marina Baldi Institute of Biometeorology National Research Council Rome, Italy

Theodore C. Crusberg Biology and Biotechnology Worcester Polytechnic Institute Worcester, Massachusetts xi

xii

Contributors

Nicolas R. Dalezios Department of Civil Engineering University of Thessaly Volos, Greece

Saeid Eslamian Department of Water Engineering Isfahan University of Technology Isfahan, Iran

and Department of Natural Resources and Agricultural Engineering Agricultural University of Athens Athens, Greece

Noureddine Gaaloul Department of Water Resources National Institute of Research in Rural Engineering of Water and Forestry Tunisia, Turkey

Alireza Davari Department of Water Engineering Tarbiat Modares University Tehran, Iran

Jennifer A. Gelmini Design Project Manager Denver Water Denver, Colorado

Soleyman Dayani Department of Agricultural Biotechnology Payame Noor University Tehran, Iran

Matin Ghaheri Department of Agronomy and Plant Breeding Razi University Kermanshah, Iran

Maria Aparecida de SáXavier Pos-doutoranda em Geografia University of Federal do Espirito Santo Brazil Espirito Santo, Brazil

Albrecht Gnauck Chair of Ecosystems and Environmental Informatics Brandenburg University of Technology Cottbus-Senftenberg Cottbus, Germany

Gonzalo Delacámara Department of Economics Madrid Institute for Advanced Studies in Water Madrid, Spain Amelia Díaz Water Research Institute and Department of Public Economy, Political Economy and Spanish Economy University of Barcelona Barcelona, Spain Kasra Esfehani Plant Bioproducts Department National Institute of Genetic Engineering and Biotechnology (NIGEB) Tehran, Iran Saleh Tarkesh Esfahany Department of Environmental Engineering Islamic Azad University—Research and Science Branch Tehran, Iran

Alireza Gohari Department of Water Engineering Isfahan University of Technology Isfahan, Iran Saeed Gohari Department of Water Engineering Bu-Ali Sina University Hamedan, Iran C. Mario Gómez Department of Economics Madrid Institute for Advanced Studies in Water and Universidad de Alcalá Madrid, Spain Mahdi Hadipour Department of Plant Breeding and Biotechnology Sari Agricultural and Natural Resources University Sari, Iran

xiii

Contributors

Evan Hajani School of Computing, Engineering and Mathematics University of Western Sydney Penrith, Sydney, Australia Shafi Noor Islam Department of Geography and Development and Environmental Studies Universiti Brunei Darussalam Brunei, Darussalam

Ali Ashraf Mehrabi Department of Agronomy and Plant Breeding Ilam University Ilam, Iran Nazanin Mohammadzade Miyab Department of Water Engineering Isfahan University of Technology Isfahan, Iran

Meysam Malekian Jabali Department of Water Engineering Isfahan University of Technology Isfahan, Iran

Saumitra Mukherjee Department of Geology Remote sensing and Space Sciences School of Environmental Sciences, Jawaharlal Nehru University New Delhi, India

Danial Kahrizi Department of Agronomy and Plant Breeding Razi University Kermanshah, Iran

Tadanobu Nakayama Center for Global Environmental Research National Institute for Environmental Studies Tsukuba, Japan

Ezatollah Karami College of Agriculture Shiraz University Shiraz, Iran

Marine Nalbandyan Institute of Geological Sciences National Academy of Sciences Yerevan, Armenia

Marzieh Keshavarz Department of Agriculture Payame Noor University Tehran, Iran

Rouzbeh Nazari Department of Civil and Environmental Engineering Rowan University Glassboro, New Jersey

Solmaz Khosravi Department of Plant Molecular Technology Agricultural Biotechnology Research Institute of Iran Karaj, Iran Benoit Laignel Département pédagogique d’appartenance University of Rouen Rouen, France Hamideh Maleksaeidi Department of Agricultural Extension College of Agriculture University of Kurdistan Tehran, Iran

Sara Nazif School of Civil Engineering College of Engineering University of Tehran Tehran, Iran Saeid Okhravi Department of Water Engineering Bu-Ali Sina University Hamedan, Iran Oluwagbenga O.I. Orimoogunje Department of Geography Obafemi Awolowo University Ile-Ife, Nigeria

xiv

Gideon Oron Zuckerberg Water Research Institute Jacob Blaustein Institute for Desert Research Ben-Gurion University of the Negev Negev, Israel C. Dionisio Pérez-Blanco Natural Hazard Group Fondazione Eni Enrico Mattei and Centro Euro-Mediterraneo sui Cambiamenti Climatici Venice, Italy Qin Qian Department of Civil and Environmental Engineering Lamar University Beaumont, Texas Ataur Rahman School of Computing, Engineering and Mathematics University of Western Sydney Penrith, Sydney, Australia Sandra Reinstädtler Chair of Environmental Planning Brandenburg University of Technology Cottbus-Senftenberg Cottbus, Germany Mohammad Naser Reyhani Department of Water Engineering Isfahan University of Technology Isfahan, Iran Giuseppe Rossi Institute of Hydraulics, Hydrology and Water Management University of Catania Catania, Italy Mohammad R. Sabzalian Department of Agronomy and Plant Breeding College of Agriculture Isfahan University of Technology Isfahan, Iran

Contributors

Miquel Salgot Water Research Institute and Department of Natural Products Vegetal Biology and Soil Science University of Barcelona Barcelona, Spain Shamsuddin Shahid Department of Civil Engineering Universiti Teknologi Malaysia Johor, Malaysia Hamed Tavakolifar School of Civil Engineering College of Engineering University of Tehran Tehran, Iran Samina Mazumder Tuli Department of Architecture Bangladesh University of Engineering and Technology Dhaka, Bangladesh Peter Wade School of Environmental Science North-West University South Africa Xiao-jun Wang State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing, China Kamana Yadav Biogeochemistry Division Council of Scientific and Industrial Research-National Institute of Oceanography Regional Centre Visakhapatnam, Andhra Pradesh, India Yohannes Yihdego Geotechnique Department Snowy Mountains Engineering Corporation Sydney, New South Wales, Australia Mohammad Javad Zareian Department of Water Engineering Isfahan University of Technology Isfahan, Iran

1 Drought Vulnerability 1.1 Introduction .......................................................................................... 1 1.2

1.3

Drought Vulnerability  •  Drought Sensitivity

Factors Governing Drought Vulnerability ....................................... 3 Meteorological Drought Vulnerability  •  Hydrological Drought Vulnerability  •  Vegetative and Agricultural Drought Vulnerability • Socioeconomic Drought Vulnerability  •  Droughts and Vulnerability of Women

Vulnerability Assessment ....................................................................6 Field-Based Survey  •  Remote Sensing Survey

Chandrashekhar Bhuiyan Sikkim Manipal Institute of Technology

1.4 Drought Frequency Analysis ............................................................ 10 1.5 Reliability, Resilience, and Vulnerability .........................................11 1.6 Vulnerability, Probability, and Risk .................................................11 1.7 Drought Vulnerability Reduction .................................................... 13 1.8 Summary and Conclusions ............................................................... 14 Author............................................................................................................... 14 References........................................................................................................ 14

Abstract  Drought has significant adverse effects on agricultural, environmental, and ­socioeconomic conditions. Inadequate precipitation, heat waves, scarcity of water resources, and crop failure make people vulnerable to droughts. Vulnerability to drought impacts varies in different degrees from place to place due to variations in climate, land use/land cover, agricultural practices, social ­structures, and financial support. Drought vulnerability is closely associated with risk and resilience of a society to drought. Therefore, the assessment of drought vulnerability is very important for proper water resources management and sustainable development. However, the assessment of drought vulnerability is not straightforward and requires monitoring, analysis, and evaluation of numerous factors that are directly or indirectly associated with drought development and intensification. In this chapter, drought vulnerability and its various aspects have been discussed in detail. The main objective of this chapter is to explain the concept of drought vulnerability, its nature, and controlling factors. Since droughts are intense, prolonged, and more frequent in arid and semiarid regions, such regions are comparatively more vulnerable to droughts. People, especially women, in underdeveloped regions of the world are highly vulnerable to drought impacts. These specific aspects also have been highlighted in this chapter.

1.1  Introduction The Latin word vulnerare meaning “to wound” shapes the most basic definition of vulnerability as “the capacity to be wounded” [15]. Vulnerability literally means the degree to which a system is susceptible to a specific natural hazard. Vulnerability may also refer to exposure of a system to a hazard, 1

2

Handbook of Drought and Water Scarcity

combined with its capacity to react. The definition of vulnerability varies among different spheres since one definition does not fit in all the cases. However, in spite of variation in definition, in broader sense, vulnerability indicates the extent of inability of defense of a system to a specific natural hazard. Vulnerability assessment of a system is important since it plays a critical role in the relationship between hazards and society [35]. Vulnerability of a system changes with time due to interactions of the concerned system with its surroundings as well as due to technological developments and modifications in policies. It can vary even seasonally from extremely critical to completely safe [10]. Drought is a unique natural hazard, for which initiation and termination are difficult to demarcate. Drought being the slowest natural hazard often escapes the public attention but has widespread impacts on diverse spheres. The direct and immediate impacts of droughts include decline in groundwater levels, depletion of water resources leading to scarcity of drinking and irrigation water, reduced agricultural production and productivity, inadequacy of fodder, reduced food security, and death of cattle. As an indirect effect, droughts aggravate poverty, mass migration, and societal changes. Most importantly, drought causes maximum damage to the ecology and economy of a country as compared to other natural hazards in isolation and even in combination. Therefore, the assessment of drought vulnerability of a region is very important for its people, society, ecology, and economy and its sustainable development.

1.1.1  Drought Vulnerability Drought vulnerability refers to the susceptibility of a region to the adverse effects of drought. Drought v ulnerability is dependent upon several factors and varies with respect to space and time. ­ Drought vulnerability is a complex issue since the definition of drought changes with parameters and spheres, and initiation and termination of a drought event are difficult to demarcate. Besides, drought can be defined and its severity can be assessed in terms of both drought-causative and drought-­ responsive parameters. Thus, it is highly possible that a region with adequate water resources from an alternate source may be vulnerable to meteorological drought (i.e., sudden reduction in precipitation) but is resilient to vegetative drought. Moreover, drought vulnerability assessment is dependent also on drought monitoring parameters and indices. Thus, while certain parameter or index indicates the occurrence of drought of a particular intensity, other parameters may report a different intensity drought or even “no drought” condition at the same time and place [5]. Therefore, instead of depending on a single parameter or index, drought vulnerability should be assessed on the basis of several parameters and indices.

1.1.2  Drought Sensitivity Sensitivity of a system to the causative and triggering factors of drought makes it vulnerable to drought. The most important key parameter to drought occurrence is precipitation (i.e., sudden decrease in precipitation). Heat waves too possess the capability to generate thermal stress and moisture stress in air, soil, and vegetation and intensify drought events [3]. An adequate amount of precipitation at regular intervals not only ensures “normal” supply of water to the society and moisture to vegetation but also reduces the air and land surface temperatures and thereby controls the thermal stress. The sensitivity of plants and animals including human beings to moisture stress and thermal stress varies depending upon various other parameters such as age, stage of growth, season, duration of ongoing drought, and interval between recurrent droughts. Since the degree of dependency of vegetation to moisture varies from one plant type to another and from the juvenile to mature stage of plant growth, the sensitivity of vegetation to moisture stress and thermal stress varies among different plant species and at different stages of phenological cycle. For example, xerophytes are less sensitive to moisture stress and thermal stress in comparison with phreatophytes since the former group of plants are adapted to arid and hyperarid climates and have less water demand. Similarly, the sensitivity of a society to droughts depends

Drought Vulnerability

3

upon the availability of water resources and water reserve for domestic, agricultural, and industrial supply. Drought sensitivity of the same system may vary temporally depending upon the season, demand, drought severity, and duration.

1.2  Factors Governing Drought Vulnerability Drought vulnerability of a region is governed by several factors of different kinds. The factors may be both natural and anthropogenic. Natural factors may be meteorological, hydrological, and ecological, while anthropogenic factors include socioeconomic and land use parameters. Drought impact varies due to the combination and spatiotemporal variation of these various factors.

1.2.1  Meteorological Drought Vulnerability Meteorological drought refers to the abrupt absence of or deficiency in precipitation in comparison with the “normal” condition. The “normal” precipitation is represented by long-term mean value (generally 30 years or more) of precipitation of the concerned station or region. Meteorological drought vulnerability, therefore, refers to the chance or probability of occurrence of deficient precipitation (rainfall or snowfall). This is measured in terms of frequency of deficient precipitation, which is computed by dividing the number of years of deficient rainfall (i.e., less than average rainfall) by the total number of years of past rainfall records. Although the lack of precipitation is the main cause of meteorological drought, vulnerability of a region to meteorological drought is also dependent on other factors such as heat waves and delay in the arrival and/or early retreat of the monsoon. Meteorological drought may also occur at a region in spite of above-normal seasonal precipitation, if the precipitation occurs within limited rainy days and the rest of the season remains dry. Therefore, the number of rainy days is also a very important factor in determining the meteorological drought vulnerability of a location or region.

1.2.2 Hydrological Drought Vulnerability Hydrological drought occurs due to frequent or prolonged meteorological droughts. Vulnerability of a basin or terrain to hydrological droughts is, therefore, highly influenced by meteorological droughts in various durations and intensities. However, although the occurrence of meteorological droughts is the prime factor, it is not the sole factor to determine the hydrological drought vulnerability of a region. Numerous factors are influential and responsible for vulnerability of a region to hydrological drought. These factors have a different degree of relative influence on the hydrological regime of a region, and therefore, the vulnerability of a particular region to hydrological drought is determined by various permutations and combinations of these governing factors. The following key factors govern the hydrological drought vulnerability of a region in various capacities:

1. Normal rainfall 2. Mean rainfall deficiency 3. Frequency of (weighted) deficient rainfall 4. Mean maximum temperature 5. Number and capacity of active surface water bodies 6. Productivity of wells and/or discharge of springs and streams 7. Mean groundwater draft in the nondrought seasons/years 8. Availability and adequacy of groundwater resource 9. Mean recharge of aquifers and storage in reservoirs

Normal rainfall is represented by long-term average rainfall. Generally, normal rainfall is computed by 30 years moving average. High value of normal rainfall is advantageous for a drought-prone region, but high normal precipitation may result due to abnormally high precipitation values in certain years.

4

Handbook of Drought and Water Scarcity

Therefore, the frequency of occurrence of normal or above-normal precipitation is more crucial in determining drought vulnerability. A region with high but inconsistent precipitation is more vulnerable to drought in comparison with a region with comparatively low but consistent precipitation. Drought ­v ulnerability of a region in a particular drought year increases with increase in the amount of rainfall deficiency. It may happen that at a place mean rainfall deficiency is small but frequency of occurrence of below-normal rainfall is substantially high. In that case, the region would be vulnerable to drought. During the computation of drought vulnerability, proper importance and weightage have to be given to the amount of deficient rainfall and frequency of occurrence of rainfall with different deficiency amount. Temperature also plays an important role in determining drought vulnerability since occurrence of heat waves and rise in temperature increase evapotranspiration as well as domestic, agricultural, and industrial demand for water. Therefore, a region associated with frequent heat waves and a high value of mean maximum temperature is more susceptible to droughts. During droughts, water scarcity and demand for water increase manyfold. The presence of active surface water bodies like ponds, lakes, tanks, reservoirs, springs, and streams substantially reduces hydrological drought vulnerability. If and when such water bodies are dried up, water scarcity pops up and a region suddenly becomes vulnerable to droughts. The same situation occurs if a region is solely or dominantly dependent on groundwater resources, and the wells get dried up or their productivity reduces substantially. If two locations enjoy an equal amount of groundwater recharge, then a region with high recharge coefficient (fraction of precipitation that contributes to the recharge of aquifers) but moderate precipitation is less vulnerable to groundwater drought than a region with high precipitation but low recharge coefficient. Apparently, contrary might be the case for meteorological drought vulnerability. Besides, a higher rate of extraction and a gross consumption of limited groundwater resources during the nonmonsoon period make a region more vulnerable to hydrological drought since the demand is high and the supply is low during droughts. Rising population, irrigation, industrialization, and urbanization are responsible for overexploitation of groundwater, resulting in the drying up of shallow aquifers. Unplanned development and improper management of water resources for irrigation has also led to a severe imbalance in the distribution of water. This causes scarcity of water and makes regions vulnerable to hydrological droughts in several parts of the world.

1.2.3  Vegetative and Agricultural Drought Vulnerability Vegetative and agricultural droughts are a manifestation of meteorological and hydrological droughts. Vegetative droughts refer to the degradation in the health of vegetation, both natural and agricultural, due to deficiency in rainfall, whereas agricultural droughts refer to the damage only of agricultural crops due to water scarcity. Since the adaptation of natural vegetation to climate and extreme climatic conditions, particularly drought, is different from that of agricultural crops, the vulnerability of natural vegetation and agricultural crops differs even at the same region. While natural vegetation gets adapted to extreme and adverse climatic conditions (rainfall, temperature, humidity, etc.), agricultural crops require special care and treatment such as irrigation, shades from the scorching sun, pesticides, and fertilizers to tackle adverse conditions, droughts in particular. Decline in water availability and irrigated area has a ripple effect throughout the agroeconomic system. Drought vulnerability of vegetation, both natural and agricultural, is governed by numerous factors. Some of them are common to the factors governing hydrological drought vulnerability, whereas certain factors are exclusively crucial for agricultural drought. Agricultural drought vulnerability in Nebraska, USA, was assessed [35] using four criteria: (1) probability of seasonal crop moisture deficiency, (2) soil root zone available water-holding capacity, (3) land use types, and (4) access to irrigation. However, criteria for evaluation of agricultural drought vulnerability of a region may include many more factors such as

1. Normal rainfall 2. Number of rainy days 3. Frequency of rainfall and mean interval between consecutive rainy days

Drought Vulnerability



5

4. Mean rainfall deficiency and frequency of deficient rainfall 5. Average crop water requirement 6. Average water demand and availability of water resources for irrigation 7. Minimum, maximum, and mean temperatures (during cropping seasons) 8. Number of heat wave days

Heat waves and temperature greatly damage vegetation health, both directly and indirectly [4]. As a direct effect, high temperature imparts thermal stress and damages the plant tissues by burning, and as an indirect effect, it imparts moisture stress on vegetation by increasing evaporation and transpiration. Although temperature plays an important role in determining vegetative drought vulnerability, precipitation (rainfall in particular) is the key factor in combating drought and in reducing drought vulnerability. This is because rainfall not only supplies moisture to the soil and vegetation but also attenuates the impact of thermal stress [7]. With higher average rainfall, more number of rainy days, and higher frequency of adequate rainfall, a region is less prone to vegetative drought. Agricultural drought vulnerability depends also on crop water demand and timely supply of irrigation water. Regions with crop having less water demand are comparatively less prone to drought than hydrophilic plants. For natural vegetation, xerophytes such as cactus require lesser amount of water to survive than phreatophytes (eucalyptus, sugarcane, etc.), and hence, the former are least affected, while the latter are easy prey of droughts. Due to this reason, there is an ongoing trend for change in crops and cropping patterns in relation to ongoing climate change. Arid and semiarid regions with active surface water bodies can manage water supply in the initial phase of drought and can withstand the initial blow of a drought. Therefore, regions with active surface water bodies are less affected by droughts. Similarly, regions with high aquifer recharge and high well yield can meet the sudden rise in water demand during droughts through groundwater resources and thus are less affected. On the contrary, regions devoid of adequate water resources for irrigation are highly dependent on precipitation. During droughts, most of the agricultural lands in such regions remain uncultivated, resulting in a reduction in crop yield.

1.2.4  Socioeconomic Drought Vulnerability Drought damages not only the ecology but also the economy of a state and country. Vulnerability of the society to drought varies from one profession to another and from one location to another depending upon their dependence directly on agriculture and indirectly on precipitation. A poor monsoon looms threat not only to crop yield but also to the country’s annual production and economic growth. Availability of irrigation facilities, alternate source for public supply of drinking water, reserve of foods, etc., help in combating drought impact and in reducing socioeconomic drought vulnerability. Any scarce item influences social structure and gets distributed in accordance with power of groups. Water is no exception, particularly during droughts. As per the local social hierarchy, ownership of a private well and power to purchase water, a water tap, and a water tank are found in a descending order of status, particularly in less developed regions and countries [27]. During water scarcity and droughts, water becomes precious and the luxury of water purchasing can be afforded only by the families with a fixed, regular income and some extra savings for survival. Consecutive droughts affect the economic and social life of people more severely. As a direct effect of drought, cropping fails and acute shortage of drinking water results. In a chain reaction, shortage of fodder, food, and water forces people to reduce their cattle. Another important aspect of drought impact on a section of agrarian rural population is their increasing dependence on animal husbandry or other low-skilled and low-income professions for livelihood. The lack of experience, resource, and expertise again makes them more vulnerable. Prolonged or recurrent droughts in the long run push many families from higher- to lower-income level and even to below poverty level. In other words, people have become poorer both in relative and absolute terms. Droughts force people, particularly farmers, to deepen their existing wells or to drill new bore wells and invest in higher horsepower pumpsets in an effort to meet

6

Handbook of Drought and Water Scarcity

with critical irrigation and livestock needs. Required money is managed through borrowing, mostly from traders and moneylenders, often at a very high rate of interest [27]. Drought also causes displacement and mass migration of people from the drought-affected area to the nonaffected regions. The migration pattern varies from place to place and from one community to another. While some people migrate to the places of their relatives, others move to places that offer jobs or alternate source of living. In the former case, generally the whole family migrates, whereas in the latter case mostly the menfolk migrate. A prolonged drought causes severe water scarcity and acute shortage in drinking water supply. In many parts of the world, particularly in Southeast Asia and Africa, water is rationed and supplied on a daily or weekly basis during severe droughts. In various parts of India, drought is recurrent in nature. Due to repeated failure of monsoon, water scarcity, drought, and famine cause natural death as well as suicides. Mass suicides by farmers due to drought and agricultural failures have become common news, particularly from the Vidarbha region of the Maharashtra state of India. In the recent past, looting of water tanks, quarrels, and even rioting due to water scarcity have been reported from the Bundelkhand region of Madhya Pradesh and Uttar Pradesh states and other parts of India during droughts. These alarming events are warnings of a possible future civil war and are reminders of Ismail Seregin’s prophecy that the Third World War will be fought on water!

1.2.5  Droughts and Vulnerability of Women Women are vulnerable to natural hazards, particularly to droughts, since in most parts of the world, management of the household works and welfare of the home are in the hands of women, willingly or unwillingly. In arid and semiarid regions, water scarcity is more acute. Collection and fetching of water from distant sources is another big responsibility of the womenfolk. A significant aspect of the water scarcity is that the burden of bringing water from distant sources has fallen on women, irrespective of age. Women in several rural and even in urban households have to face hardships because of lack of easy access to water for domestic uses. Therefore, women face the obvious burden of drinking water arrangement and management during droughts as demand for water increases manyfold. In other words, women are vulnerable to sufferings during droughts. Droughts do not affect all women in the same manner. In spite of some common problems and ­characteristics, there are some differences in priorities and roles of women across time, space, and classes. In underdeveloped countries, women in the rural area are directly affected by the availability or nonavailability of water because of their roles as the prime water arrangers, managers, and end users [32]. Particularly in developing and underdeveloped countries, both women and girls often spend a substantial amount of time per day to fetch water from distant places. Such hardships adversely affect them, and the sufferings increase manyfold by the occurrence of droughts. However, the worst consequence of recurring droughts is trafficking, selling, and forced prostitution of women. Poverty and famine resulted due to extreme or recurrent droughts that leave no other option for some poor people but to engage their womenfolk into prostitution or even to sell them in exchange for money. At the time of desperation such as droughts, women become the breadwinner but through extreme sufferings.

1.3  Vulnerability Assessment Assessment of drought vulnerability is a challenging task since a region may possess a different degree of vulnerability to different types (meteorological, hydrological, agricultural, socioeconomic, etc.) of droughts. Besides, drought vulnerability of the same region may vary with respect to time. The assessment of drought vulnerability is dependent on information and data of various types, sources, and domains. The determining factors of drought vulnerability assessment also influence the process and the results. Therefore, prospects and consequences of data and parameter selection in drought vulnerability assessment must be considered and estimated a priori. Drought vulnerability assessment may be carried out through field-based survey, remote sensing survey, or their combination. There are certain

7

Drought Vulnerability

specific advantages as well as limitations to both field-based and remote sensing survey. Therefore, a combination of both methods is pragmatic and effective in drought vulnerability assessment.

1.3.1  Field-Based Survey Ground data of various drought-causative and drought-responsive parameters are most reliable in the evaluation of drought vulnerability of a region since they provide direct information about drought severity. However, ground data are either unavailable or difficult to obtain till date for many parameters in many parts of the world. For example, procurement of ground data of precipitation and temperature is relatively easier than actual evapotranspiration, streamflow, spring discharge, soil moisture, etc. Groundwater level and well yield data from various aquifers are not easy to obtain in many countries either due to lack of infrastructure or due to official formalities or data restrictions. Similarly, reliable data of cattle death and mass migration of people during droughts are difficult to obtain due to lack of records or lack of accessibility. Since a close relationship exists between crop yield and water stress, the former is a reliable indicator of agricultural drought [23]. Therefore, crop yield in response to water stress is a critical factor for the assessment and prediction of agricultural drought risk, which is, however, difficult to evaluate due to variation in the sensitivity of crop to water stress [37]. Since field data provide direct information regarding the drought-causative and drought-responsive parameters, field-based survey offers a detailed and more authentic picture of droughts. Assessment of drought and drought vulnerability is carried out with the help of certain drought-causative and/ or drought-responsive parameters and indices based on such parameters. For the analysis of meteorological drought, the assessment parameters such as rainfall, temperature, and potential evapotranspiration are effectively used in the form of index. An index value is more convenient and meaningful in expressing the severity of drought. For the hydrological drought assessment, indices based on soil moisture, streamflow, spring discharge, seasonal groundwater level, and fluctuation of water table are used. Standardized water-level index (SWI) and water-level fluctuation index (WFI) are two such indices (Tables 1.1 and 1.2) developed for the assessment of groundwater drought. The SWI [5,6] monitors the seasonal groundwater level in wells and compares it with the long-term mean and assesses drought intensity by evaluating the amount of deviation from the “normal.” The SWI can be expressed as SWI =



WL o - WL m s

(1.1)

where WLo is the observed seasonal water level for the ith well and jth observation WLm is the seasonal mean σ is the standard deviation TABLE 1.1  Standardized Water-Level Index Classification Standardized Water-Level Index Value ≤0.0 >0.0 >1.0 >1.5 >2.0

Drought Class No drought Mild drought Moderate drought Severe drought Extreme drought

Source: Bhuiyan, C., Various drought indices for monitoring drought condition in Aravalli terrain of India, in Proceedings of the XXth ISPRS Conference, International Society of Photogrammetry and Remote Sensing, Istanbul, Turkey, 2004.

8

Handbook of Drought and Water Scarcity TABLE 1.2  Water-Level Fluctuation Index Classification Water-Level Fluctuation Index Value ≥−0.125 ≥−0.25