DROUGHT RISK REDUCTION IN INTEGRATED WATER RESOURCES MANAGEMENT Cover photo: Andrés Callizaya Barrientos – Second place at Cap-Net photo & art contest 2020 edition DROUGHT RISK REDUCTION IN INTEGRATED WATER RESOURCES MANAGEMENT Revised by the Integrated Drought Management Programme (IDMP) Contents Foreword.............................................................................................................................................................................vii Glossary ...............................................................................................................................................................................ix 1 Introduction to integrated drought management..................................................................................................... 1 1.1 An introduction to droughts ..................................................................................................................................................2 1.1.1 Drought impacts ........................................................................................................................................................2 1.1.2 Drought – definition and characteristics .................................................................................................................3 1.1.3 Meteorological causes for droughts .......................................................................................................................4 1.1.4 Impacts of drought and climate change .................................................................................................................6 1.1.5 Drought risk reduction ...............................................................................................................................................7 1.2 Water and drought management approaches ...................................................................................................................8 1.2.1 Integrated water resources management ..............................................................................................................8 1.2.2 Proactive approach to drought management ......................................................................................................10 1.2.3 Integrated drought management and the three pillars .....................................................................................11 1.3 Overview of relevant international processes ..................................................................................................................12 1.3.1 High-Level Meeting on National Drought Policies ................................................................................................12 1.3.2 Integrated Drought Management Programme ...................................................................................................12 1.3.3 Sustainable Development Goals .............................................................................................................................12 1.3.4 The United Nations Framework Convention on Climate Change and the Paris Agreement on climate change 13 1.3.5 Sendai Framework for Disaster Risk Reduction....................................................................................................13 1.3.6 The United Nations Convention to Combat Desertification ...............................................................................14 1.4 References and further reading ..........................................................................................................................................15 1 ii 2 Monitoring and early warning (Pillar 1) ..................................................................................................................... 18 2.1 Introduction to drought monitoring and early warning systems ..................................................................................19 2.2 Understanding and measuring hydrological and climatological parameters ...............................................................19 2.2.1 Hydrological cycle .....................................................................................................................................................19 2.2.2 Methods for hydro-meteorological data collection ..............................................................................................21 2.3 Drought indicators and indices ...........................................................................................................................................23 2.3.1 Standardized Precipitation Index ...........................................................................................................................28 2.3.2 Palmer Drought Severity Index ..............................................................................................................................29 2.3.3 Soil Moisture Deficit Index.......................................................................................................................................29 2.3.4 Water Requirement Satisfaction Index ..................................................................................................................29 2.4 Drought monitoring and forecasting products .................................................................................................................30 2.4.1 Example: United States Drought Monitor .............................................................................................................30 2.4.2 Example: DriDanube DroughtWatch .....................................................................................................................31 2.4.3 Example: North-east Brazil Drought Monitor ......................................................................................................33 2.5 Drought early warning systems ..........................................................................................................................................33 2.5.1 Famine Early Warning Systems Network ..............................................................................................................35 2.6 References and further reading ..........................................................................................................................................36 2 iii 3 Drought vulnerability and impact assessment (Pillar 2) ........................................................................................ 38 3.1 Introduction to drought vulnerability and impact assessment .......................................................................................39 3.1.1 Drought risk – linking hazard, exposure and vulnerability ..................................................................................39 3.1.2 Drought impacts .......................................................................................................................................................39 3.1.3 Understanding drought vulnerability.....................................................................................................................41 3.1.4 Drought risk management and gender .................................................................................................................45 3.2 Framework for impact and vulnerability assessment ......................................................................................................46 3.2.1 Task A – scoping phase ............................................................................................................................................48 3.2.2 Task B – impact assessment....................................................................................................................................48 3.2.3 Task C – vulnerability assessment ..........................................................................................................................48 3.3 Methods for impact and vulnerability assessments .........................................................................................................49 3.3.1 Overview of methods, tools and datasets for impact and vulnerability assessments ....................................49 3.3.2 The use of indicators and indices in impact and vulnerability assessment ......................................................52 3.4 Case studies ...........................................................................................................................................................................54 3.4.1 Case study 1: Assessing vulnerability to drought at the basin level in Mexico ................................................54 3.4.2 Case study 2: Surveying, profiling and evaluating vulnerability to drought in Ethiopia .................................55 3.5 References and further reading ..........................................................................................................................................56 3 iv 4 Drought mitigation, preparedness and response (Pillar 3) .................................................................................... 59 4.1 Introduction to drought management planning ...............................................................................................................60 4.2 Overview of drought preparedness, mitigation, response and recovery .....................................................................60 4.2.1 Definitions and context ...........................................................................................................................................60