Ph.D. Thesis M. B. Patel

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Acknowledgement I

Executive Summary III

List of Tables XIV

List of Graphs XVI

List of Figures XVIII

Abbreviations XXII

Chapter Title Page

1 INTRODUCTION

1-9

1.1 Rivers of Gujarat

2

1.2 Estuaries

4

1.2.1 The Estuary Definitions 4

1.3 Sea Water Intrusion Problem in Coastal Aquifers 5

1.3.1 Abrupt Interface Approach 6

1.3.2 Hydrodynamic Dispersion Approach 6

1.3.3 Sea Water Intrusion Problem in Coastal Aquifer Overlain

by an Estuary 6

1.4 Purpose of Artificial Recharge Structures in Estuarine Area 7

1.5 Scope and Objectives of The Study 7

1.6 Closure 9

2 LITERATURE REVIEW 10-29

2.1 Estuaries and Related Problems 10

2.1.1 Engineering Problems in Estuaries 10

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2.2 Estuary Dynamics 11

2.2.1 Salinity Transport in Estuaries 12

2.2.2 Estuary Mixing Types 12

2.2.2.1 Highly Stratified Type 13

2.2.2.2 Partially Mixed Type 13

2.2.2.3 Well-Mixed Type 14

2.2.3 Estuarine Area’s Problems of World 15

2.2.4 Estuarine Area’s Problems of India 17

2.3 Surface Water Models for Estuarine Area 17

2.4 Water Quality Studies in Estuarine Area 20

2.5 Coastal Groundwater Models 24

3 CASE STUDY AREA AND DETAILS 30-54

3.1 Study Area 31

3.1.1 Geographical Location of Study Area 31

3.2 Mahi River 34

3.2.1 Mahi Basin 35

3.2.2 Tributaries of Mahi 36

3.2.2.1 Mini River 37

3.2.3 Water Resources Projects on River Mahi 37

3.2.3.1 Mahi Right Bank Canal Project 38

3.2.3.2 Mahi Right Bank Canal Command Area 38

3.2.3.3 Radial Collector Wells 39

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3.2.3.4 Mahi Tidal Regulator Cum Recharge Scheme 41

3.2.4 Water Resources Projects on Tributaries of River Mahi 42

3.3 Mahi Estuary 42

3.3.1 Tidal Range in Mahi Estuary 43

3.4 Details of Study Area 44

3.4.1 Topography of Study Area 44

3.4.2 Climate of Study Area 44

3.4.3 Temperature of Study Area 45

3.4.4 Humidity 45

3.4.5 Cloudiness 46

3.4.6 Winds 46

3.4.7 Rainfall 46

3.4.8 Special Weather Phenomena in Study Area 47

3.4.9 Geology 47

3.4.10 Soils in the Study Area 48

3.4.11 Vadodara Branch Canal 52

3.4.12 Effluent Channel Project, Vadodara (E.C.P.) 53

4 DATA COLLECTION & METHODOLOGY 55-96

4.1 RL’s of Mahi River Water Level 55

4.2 RL’s of Ground Level of Wells and River Bed 59

4.3 RL’s of Bottom of Wells in Unconfined Aquifer 59

4.4 Horizontal Permeability ‘HK’ Of Wells in an Unconfined

Aquifer 59

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4.5 Specific Yield ‘Sy’ of Wells in Unconfined Aquifer 60

4.6 Lithology Data 61

4.7 Reduced Water Level of Wells 61

4.8 Water Quality Data of Wells 67

4.9 Rainfall Data 70

4.10 Recharge Data 71

4.11 Conductance for the River 72

4.12 GMS 6.0 Software 76

4.12.1 MODFLOW 76

4.12.2 The Conceptual Model Approach 77

4.12.3 Advantages of the Conceptual Model Approach 77

4.12.4 Groundwater Flow Equation Used In MODFLOW 78

4.13 Groundwater Modelling 81

4.13.1 Assumptions and Considerations in Model Analysis 82

4.13.2 Construction of the Model for the Study Area 82

4.13.2.1 Base Map Preparation 83

4.14 Conceptual Model of the Aquifer System 83

4.14.1 Fence Diagram, Solids and Longitudinal Sections 84

4.15 Three Dimensional Model for Present Study 88

4.15.1 Setting up the Recharge Zones 88

4.15.2 Setting up the Horizontal Permeability Zones 88

4.15.3 Setting up the Specific Yield Zones 89

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4.15.4 Setting up the Location of River Mahi 89

4.16 Creating the 3D Grid 90

4.17 Starting Heads to the Model 91

4.18 Boundary Conditions 92

4.19 Regression Analysis 95

4.19.1 Year Wise Variation in TDS With Reference to Rainfall 96

5 MODEL SIMULATION 97 -136

5.1 Calibration of Groundwater Model 97

5.1.1 Automated Parameter Estimation 99

5.1.2 Period of Calibration Simulation 99

5.1.3 Input Parameters for Calibration 99

5.1.4 Setting up the Stress Periods 102

5.1.5 Results of Calibration 103

5.2 Validation of Groundwater Model 107

5.2.1 Period of Validation Simulation 108

5.2.2 Input Parameters for Validation 108

5.2.3 Setting up the Stress Periods 109

5.2.4 Results of Validation 110

5.3 Predictive Groundwater Modelling 112

5.3.1 Period of Predictive Simulation 113

5.3.2 Operational Runs 113

5.3.3 Input Parameters for Predictive Simulation 115

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5.3.4 The Stress Periods 116

5.3.5 Results of Prediction Scenarios 117

6 REGRESSION ANALYSIS OF WATER QUALITY DATA 137-172

6.1 Regression Analysis 137

6.1.1 Linear Regression Analysis 138

6.1.2 Multiple Linear Regression Analysis for Three Parameters 146

6.1.3 Multiple Linear Regression Analysis for Four Parameters 152

6.1.4 Year Wise Variation in TDS With Reference to Rainfall 154

6.2 Lab Analysis for Water Quality 157

6.2.1 Graphical Analysis 159

7 RESULTS and DISCUSSIONS 173-182

7.1 Results, Discussions on Regression & Graphical Analysis 173

7.2 Results, Discussions on Lab as well as Graphical Analysis 176

7.2.1 Considering Distances from Kavi (Sea) in Mahi Estuarine

Area 176

7.2.2 Considering Distances from Mahi River in Mahi Estuarine

Area 179

7.2.3 Considering Location of Villages on Right or Left Bank 182

8 CONCLUSIONS 183-187

8.1 Summary 183

8.2 Conclusions 183

8.3 Research Contributions 186

Scope of Further Study 187

REFERENCES 188-196

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ANNEXURE 196-294

Annexure-I 197-244

Annexure-II 245-277

Annexure-III 278

Annexure-IV 279-290

Annexure-V 291-295