Evaluation of Groundwater Resources on the Coral Islands of Lakshadweep, India (SpringerBriefs in Water Science and Technology)

This book provides insights on and tools for the characterization of island aquifers, as illustrated by the example of the coral islands of Lakshadweep in India. After an initial overview of the different coral islands, subsequent chapters explain key geophysical, hydrogeological and hydrochemical methods for the assessment and characterization of coral island aquifers. The book’s closing chapters highlight selected case studies and describe actual implementations of the methods discussed. In addition to presenting the details of data collection on each island – a valuable resource for any future study on these islands – in graphical form, the book proposes suitable measures for ensuring the sustainability of groundwater resources on the islands. Accordingly, it offers a unique and essential source of information for all hydrogeologists whose work involves island aquifers. Foreword 6 Preface 8 Contents 11 1 Introduction 14 1.1 Fresh Water Resources 14 1.2 Water Resources in India 15 1.3 Coral Islands 16 1.3.1 Formation of Lakshadweep Islands 17 1.3.2 Lakshadweep Islands 19 1.3.3 Sand Banks 19 1.3.4 Reefs 21 1.3.5 Islands 21 1.3.5.1 Chetlat Island 22 1.3.5.2 Bitra Island 22 1.3.5.3 Kiltan Island 23 1.3.5.4 Kadmat Island 23 1.3.5.5 Amini Island 24 1.3.5.6 Pitti Island 25 1.3.5.7 Bangaram, Tinnakara and Parali Islands 25 1.3.5.8 Agathi Island 26 1.3.5.9 Kavaratti Island 27 1.3.5.10 Andrott Island 27 1.3.5.11 Kalpeni Island 28 1.3.5.12 Minicoy Island 29 1.3.6 Population of Lakshadweep Islands 29 References 31 2 Groundwater as Freshwater Resource 32 2.1 Introduction 32 2.2 Hydrogeology of Coral Island 32 2.3 Ghyben–Herzberg Relationship 33 2.4 Transition Zone 35 References 37 3 Delineation of Fresh Groundwater Zone on Island 38 3.1 Introduction 38 3.2 Geophysical Methods 38 3.2.1 Electrical Resistivity Method 39 3.2.1.1 Vertical Electrical Sounding 41 3.2.1.2 Interpretation 42 3.2.1.3 Type Curve Match 43 3.2.1.4 Numerical Method 43 3.2.1.5 Resistivity Imaging 44 3.2.2 Seismic Refraction Method 45 3.2.3 Electromagnetic (EM) Method 46 3.3 Hydrogeological Method 46 3.3.1 Ghyben–Herzberg Relation 46 3.3.2 Rainfall–Width–Permeability Relationship 47 3.3.3 Rainfall–Width–Lens Relationship 48 3.3.4 Analytical and Numerical Method 48 References 49 4 Characterization of Island Aquifer 52 4.1 Introduction 52 4.2 Pumping Test 52 4.2.1 Analytical Method 55 4.2.2 Numerical Method 56 4.2.3 Tidal Method 59 4.2.4 Tidal Response in Aquifer 61 4.2.5 Tidal Analysis 62 References 63 5 Chemical and Biological Characterization of Island Aquifer 64 5.1 Introduction 64 5.2 Interpretation of Data 65 5.2.1 Piper Diagram (Trilinear Graph) 65 5.2.2 Water Hazard 66 5.2.3 Gibbs Diagrams 67 5.2.4 Statistical Analysis 68 5.2.5 Water Quality Index 69 5.2.6 Anthropogenic Pollution 70 References 71 6 Management of Groundwater 72 6.1 Introduction 72 6.2 Assessment of Safe Groundwater Withdrawal 72 6.3 Water Balance 74 6.4 Numerical Model 76 6.4.1 SUTRA Model 76 6.4.2 Artificial Neural Network 78 6.4.3 Application of Geographical Information System (GIS) 79 References 79 7 Case Studies 81 7.1 Introduction 81 7.2 Kavaratti Island 81 7.2.1 Introduction 81 7.2.2 Water Supply 82 7.2.3 Hydrogeology 82 7.2.4 Groundwater Regime 84 7.2.5 Groundwater Quality 87 7.2.6 Aquifer Characterization 88 7.2.6.1 Pumping Test 89 7.2.6.2 Analysis of Pumping Test Data 91 7.2.7 Groundwater Modelling 92 7.2.7.1 Physical Framework 92 7.2.7.2 Model Run and Calibration 95 7.2.7.3 Prediction Using Model 95 7.2.8 Anthropogenic Pollution 97 7.3 Andrott Island 97 7.3.1 Introduction 97 7.3.2 Water Supply 98 7.3.3 Hydrogeology 98 7.3.3.1 Monitoring Groundwater Level and Sea Level 100 7.3.4 Geophysical Investigations 102 7.3.4.1 Interpretation 103 7.3.5 Aquifer Characterization 105 7.3.5.1 Pumping Test 105 7.3.6 Groundwater Quality 107 7.3.6.1 Graphical Data Interpretation 107 7.3.6.2 Statistical Analysis 111 7.3.7 Groundwater Pollution Due to Sewage 113 7.3.8 Conclusions 113 7.4 Kalpeni Island 114 7.4.1 Introduction 114 7.4.2 Water Supply 114 7.4.3 Physiography 115 7.4.4 Rainfall 116 7.4.5 Hydrogeology 116 7.4.5.1 Relationship of Height of Water Table and Freshwater Thickness 119 7.4.5.2 Thickness of Freshwater Lens 120 7.4.6 Groundwater Quality 122 7.4.6.1 Wilcox’s Diagram 123 7.4.6.2 Piper Diagram 124 7.4.6.3 Water Quality Index 125 7.4.7 Aquifer Characterization 128 7.4.7.1 Tidal Method 128 7.4.8 Rainwater Harvesting 130 7.4.9 Conclusions 130 7.5 Minicoy Island 130 7.5.1 Introduction 130 7.5.2 Water Supply 132 7.5.3 Physiography 132 7.5.4 Rainfall 134 7.5.5 Hydrogeological Regime 134 7.5.5.1 Relationship of Height of Water Table and Freshwater Thickness 136 7.5.5.2 Thickness of Groundwater Lens 136 7.5.6 Groundwater Quality 138 7.5.6.1 Measurement of EC and Its Variation 138 7.5.6.2 Water Hazard 140 7.5.6.3 Wilcox Diagram 140 7.5.6.4 Piper Diagram 140 7.5.6.5 Statistical Analysis 142 Correlation Analysis and Cross Plots 142 Principal Component Analysis (PCA) 145 7.5.6.6 Water Quality Index 146 7.5.7 Aquifer Characterization 147 7.5.7.1 Sea Tide 149 7.5.7.2 Determination of Aquifer Diffusivity 149 7.5.8 Awareness Program 151 7.5.9 Conclusions 151 References 152 Front Matter....Pages i-xiii Introduction....Pages 1-18 Groundwater as Freshwater Resource....Pages 19-24 Delineation of Fresh Groundwater Zone on Island....Pages 25-38 Characterization of Island Aquifer....Pages 39-50 Chemical and Biological Characterization of Island Aquifer....Pages 51-58 Management of Groundwater....Pages 59-67 Case Studies....Pages 69-142