Understanding Hydrological Variability for Improved Water Management in the Semi-Arid Karkheh Basin, Iran : UNESCO-IHE PhD Thesis

This study provides a hydrology based assessment of (surface) water resources and its continuum of variability and change at different spatio-temporal scales in the semia'arid Karkheh Basin, Iran, where water is scarce, competition among users is high and massive water resources development is under way. The study reveals that the ongoing allocation planning is not sustainable and essentially requires reformulation, with consideration of spatioa'temporal variability and observed trends in the streamflows regarding flood intensification and decline in low flows. The development of innovative me Front Cover......Page 1 TABLE OF CONTENTS......Page 18 FOREWORD......Page 6 ACKNOWLEDGEMENTS......Page 8 SUMMARY......Page 12 1.1.1. Increasing pressure on earth’s water resources......Page 22 1.1.2. Adapting sustainable solutions......Page 24 1.1.3. Managing water by river basin......Page 25 1.1.4. Need for a hydrological synthesis......Page 26 1.2.1. An overview of the water issues of Iran......Page 28 1.2.2. Description of the Karkheh Basin and problem statement......Page 31 1.3.1. Research motivation......Page 40 1.3.3. Contribution of the proposed research......Page 41 2.1. Methodological Framework......Page 44 2.1.2. System investigation......Page 45 2.1.3. Hydrological modeling......Page 48 2.2. Data Collection......Page 51 3.1 Introduction......Page 54 3.2. Data and Methods......Page 55 3.3.1. Spatial and temporal variability of daily streamflow regimes......Page 57 3.3.2. Spatial and temporal variability of monthly streamflows......Page 62 3.3.3. Long-term variability in annual surface water availability......Page 66 3.3.4. Overview of the basin-level water accounting......Page 69 3.4. Concluding Remarks......Page 72 4.1. Introduction......Page 74 4.2.1. Hydrological and climate data and indices......Page 75 4.3.1. Characterizing the streamflow regime......Page 79 4.3.2. Streamflow trends......Page 81 4.3.3. Trends in the climatic data......Page 84 4.3.4 Streamflow trends and climate linkages......Page 86 4.3.5 The impact of NAO index on the local climate......Page 91 4.4. Concluding Remarks......Page 92 5.1.1. Problem statement......Page 94 5.1.2. Review of regionalization methods using conceptual rainfall-runoff models......Page 95 5.2.1 Study catchments and available data......Page 99 5.2.2 Naturalization of the streamflows......Page 101 5.2.3. Model calibration and validation at the gauged catchments......Page 104 5.2.4. Regionalization of model parameters based on catchment similarity analysis......Page 106 5.2.5 Assessment of the impact of parameter uncertainty on the regionalization results......Page 108 5.3.1. Model results of automatic parameter estimation......Page 109 5.3.2. Regionalization results based on drainage area, spatial proximity and catchment characteristics......Page 111 5.3.3. Regionalization results based on FDC......Page 112 5.3.4. Impact of parameter uncertainty on the regionalization results......Page 114 5.3.5. Comparison of the FDC- based regionalization results with other studies......Page 115 5.4. Concluding Remarks......Page 117 6.1. Introduction......Page 118 6.2.1. Data used in the model setup......Page 120 6.2.2. Formulation of precipitation input scenarios......Page 122 6.2.3. Model calibration......Page 126 6.3.1. Comparison of precipitation input......Page 129 6.3.2. Comparison of streamflow simulations......Page 132 6.4. Concluding Remarks......Page 141 7.1 Introduction......Page 144 7.2.1. Model used for the scenario simulation......Page 145 7.2.2. Tested scenarios......Page 148 7.3.1. Downstream impact of upgrading rain-fed areas to irrigated agriculture (S1)......Page 151 7.3.2. Downstream impact of improved soil water availability through rainwater harvesting Scenario (S2)......Page 154 7.3.4. Consideration of prediction uncertainty of the model......Page 155 7.4. Summary and Concluding Remarks......Page 158 8.1. Nature and Causes of a High Level of Hydrological Variability......Page 160 8.3. Streamflow Trends and Their Underlying Causes......Page 161 8.4. Addressing Methodological and Data Scarcity Issues in the Hydrological Modeling......Page 162 8.6. Contribution and Innovative Aspects of This Research......Page 163 8.7. Major Recommendations and Future Directions......Page 164 SAMENVATTING......Page 166 REFERENCES......Page 172 LIST OF FIGURES......Page 190 Appendix A. Short description of the Hargreaves method and its application in the study basin......Page 194 ABOUT THE AUTHOR......Page 196 1. INTRODUCTION 1.1. Background 1.1.1. Increasing pressure on earth's water resources 1.1.2. Adapting sustainable solutions 1.1.3. Managing water by river basin 1.1.4. Need for a hydrological synthesis1.2. Hydrological and Water Management Issues in the Karkheh Basin, Iran1.2.1. An overview of the water issues of Iran 1.2.2. Description of the Karkheh Basin and problem statement 1.3. Research Framework 1.3.1. Research motivation 1.3.2. Research objectives and questions 1.3.3. Contribution of the proposed research2. MATERIALS AND METHODS2.1. Methodological Framework 2.1.2. System investigation 2.1.3. Hydrological modeling2.2. Data Collection3. STREAMFLOW VARIABILITY AND WATER ALLOCATION PLANNING 3.1 Introduction3.2. Data and Methods 3.3. Results and Discussion 3.3.1. Spatial and temporal variability of daily streamflow regimes3.3.2. Spatial and temporal variability of monthly streamflows 3.3.3. Long-term variability in annual surface water availability3.3.4. Overview of the basin-level water accounting 3.4. Concluding Remarks4. STREAMFLOW TRENDS AND CLIMATE LINKAGES 4.1. Introduction 4.2. Data and Methods 4.2.1. Hydrological and climate data and indices4.2.2. Trend and correlation analysis 4.3. Results and Discussion 4.3.1. Characterizing the streamflow regime 4.3.2. Streamflow trends 4.3.3. Trends in the climatic data 4.3.4 Streamflow trends and climate linkages 4.3.5 The impact of NAO index on the local climate 4.4. Concluding Remarks 5. REGIONALIZATION OF A CONCEPTUAL RAINFALLRUNOFF MODEL BASED ON SIMILARITY OF THE FLOW DURATION CURVE 5.1. Introduction 5.1.1. Problem statement 5.1.2. Review of regionalization methods using conceptual rainfall-runoff models 5.1.3. Scope and objective 5.2. Materials and Methods 5.2.1 Study catchments and available data 5.2.2 Naturalization of the streamflows 5.2.3. Model calibration and validation at the