HYDROGEOLOGY AND HYDROCHEMISTRY OF THE AQUIFER SYSTEMS OF KUTTANAD AREA, KERALA: THEIR ROLE IN UNDERSTANDING THE EVOLUTION OF GROUNDWATERS Thesis submitted to the Cochin University of Science and Technology by Vinayachandran N In partial fulfillment of the requirement for the award of the degree of DOCTOR OF PHILOSOPHY Under the Faculty of Marine Sciences Department of Marine Geology and Geophysics Cochin University of Science and Technology Cochin- 682 016 June 2014 DECLARATION I do hereby declare that the thesis entitled ‘Hydrogeology and hydrochemistry of the aquifer systems of Kuttanad area, Kerala: Their role in understanding the evolution of groundwaters’, being submitted to the Cochin University of Science and Technology, in partial fulfillment of the requirements for award of the degree of Doctor of Philosophy under the faculty of Marine Sciences, is a bona fide record of the work carried out by me in the Department of Marine Geology and Geophysics, Cochin University of Science and Technology, under the supervision of Prof. A.C. Narayana, Professor, Centre for Earth & Space Sciences, University of Hyderabad, Hyderabad (Former Professor , Department of Marine Geology and Geophysics, Cochin University of Science and Technology, Kerala) and that this thesis has not previously formed the basis for the award of any other degree. Vinayachandran N Cochin 21-06-2014 i CERTIFICATE This is to certify that the thesis entitled “Hydrogeology and hydrochemistry of the aquifer systems of Kuttanad area, Kerala: Their role in understanding the evolution of groundwaters” is an authentic record of research work carried out by Mr. Vinayachandran N, under my supervision and guidance at the Department of Marine Geology and Geophysics, Cochin University of Science and Technology, in the Faculty of Marine Sciences, in partial fulfillment of the requirements for the degree of Doctor of Philosophy and no part thereof has been presented for the award of any degree in any University/ Institute. Prof. A.C. NARAYANA Research Supervisor, Centre for Earth and Space Sciences, University of Hyderabad (Formerly Professor, Department Of Marine Geology & Geophysics, Cochin University of Science and Technology) Hyderabad 21.06.2014 ii ACKNOWLEDGEMENTS I owe immense obligation to my guide, Professor. A. C. Narayana, whose supervision was invaluable and without his proficient guidance and instigation this work would not have been possible. I place on record my sincere and heartfelt thanks to him. I acknowledge the help and support extended by Professor K. Sajan, Head, Department of Marine Geology & Geophysics. I am thankful to Prof. C.G. Nambiar and Dr. M. Ravishankar, Associate Professor, former Heads of the Department of Marine Geology and Geophysics, for their support. The support and encouragement received from the faculty, research scholars and staff of the Department of Marine Geology and Geophysics is gratefully acknowledged. I am thankful to Dr. D.K. Chadha, former Chairman, Central Ground Water Board for permitting me to do this research work. The support and encouragement extended by the Present Chairman, Dr. Susheel Gupta are thankfully acknowledged. I am very much thankful to Sri. DSC Thambi, Member (Rtd), and Regional Director, Central Ground Water Board, Trivandrum, for providing the facilities in the department. The interactions with Dr. K,Md. Najeeb, Member, Central Ground Water Board, Faridabad and Dr. P. Nandakumaran, Regional Director, Kerala Region were fruitful and I thank them for their support. The invaluable support and help extended by Sri. Biju Sebastian, Geologist, Directorate of Mining and Geology, Kerala, is also acknowledged. I express my sincere appreciation to Sri. V. Kunhambu, Sri. K. Balakrishnan, Smt. V.R. Rani, Sri. Srihari Sarangan and Sri. Santhana Subramani, my colleagues and scientists in Central Ground Water Board, for extending whole hearted support during the final stages of this work. I take this opportunity to thank the scientists of Isotope Application Division of Bhabha Atomic Research Centre, Trombay in particular Dr. Noble Jacob and Dr. Shivanna (Rtd.) for the technical support and help extended. The facilities extended by the Chemical Division of Centre for Earth Science Studies (CESS), Trivandum, and the Centre for Water Resources Development iii and Management (CWRDM), Kunnamangalam, Kozhikode are thankfully acknowledged. The geological data provided by Geological Survey of India (GSI), meteorological data provided by Indian Meteorological Department (IMD), Trivandrum and various data related to groundwater regime provided by the State Ground Water Department (SGWD), Kerala Water Authority, and various State departments of Kerala are thankfully acknowledged. The support extended by Dr. Ajith Kumar and Dr. Jiji Thomson of SGWD during the preparation of the thesis is thankfully acknowledged. Thanks are also due to my wife Abhilasha and daughter Amritha V Chandran, who stood by my side during the preparation of the thesis. I am indebted to both of for their love, affection and support. I am also thankful for the blessings, love and support of my parents, brothers and sisters, which have brought me thus far in my life. I am thankful to all the geoscientists whose hard work over the last so many years have provided me with all the basic information in the form of literature for this study. Finally, I wish to express my gratitude to the authorities of the Cochin University of Science and Technology for granting permission to work as a part-time research scholar. Vinayachandran N iv CONTENTS Page no. Declaration i Certificate ii Acknowledgements iii Contents v List of Tables viii List of Figures xi CHAPTER 1: INTRODUCTION 1-24 1.1 Background 1.2 Objectiv es and Scope of Study 1.3 Review of literature 1.4 Study area 1.5 Topography 1.6 Soils 1.7 Land use 1.8 Crops and Irrigation 1.9 Climate 1.10 Hydrology 1.11 Drainage CHAPTER 2: GEOLOGY AND GEOMORPHOLOGY 25-60 2.1 Introduction 2.2 Stratigraphic sequence 2.3 Geology of Kuttanad area 2.4 Structures 2.5 Vertical boundary and thickness of geological formations 2.5.1 Disposition of sand and clay in the sedimentary formations 2.5.2 Disposition of sand and clay in Recent alluvium 2.5.3 Stratigraphic and lithological inferences from geophysical logs in Recent alluvium 2.5.4 Composite lithologs 2.6 Geomorphology 2.7 Sea level rise along Kerala coast and its relation to Kuttanad area CHAPTER 3: MATERIALS AND METHODS OF STUDY 61-70 3.1 Introduction 3.2 Hydrometeorology 3.3 Delineation of litho units and aquifer geometry 3.4 Groundwater flow regime v 3.5 Hydrochemical studies 3.6 Radon activity in groundwater 3.7 Isotope studies 3.8 Statistical analysis 3.9 Hydrochemical facies and spatial analysis CHAPTER 4: HYDROGEOLOGY 71-108 4.1 Introduction 4.2 Hydrogeology of alluvial formations 4.2.1 Water levels in Phreatic Aquifers 4.2.2 Piezometric heads in confined aquifers 4.3 Groundwater in Tertiary formations 4.3.1 Piezometric levels in the Tertiary aquifer system 4.3.2 Trend of piezometric levels 4.4 Aquifer characteristics 4.4.1 Aquifer parameters in Recent Alluvium 4.4.2 Aquifer parameters of Tertiary aquifers 4.5 Groundwater flow and resources in Tertiary aquifers CHAPTER 5: HYDROCHEMISTRY 109-177 5.1 Introduction 5.2 Hydrochemical parameters in the surface waters 5.3 Hydrochemical parameters in the groundwater 5.3.1 Hydrogen ion concentration (pH) 5.3.2 Electrical conductivity (EC) 5.3.3 Major ion chemistry of groundwaters in aquifer systems in the area 5.3.4 Minor elements in groundwater 5.4 Hardness 5.5 Index of Base Exchange (Chloro-Alkaline Indices-CAI) 5.6 Corrosivity Ratio (CR) 5.7 Inter relationships of ions 5.8 Factor and cluster models for phreatic aquifers 5.8.1 Factor results 5.8.2 Hierarchical cluster analysis results 5.9 Factor and cluster models for Recent-confined aquifer 5.9.1 Factor analysis 5.9.2 Hierarchical Cluster Analysis 5.10 Factor and cluster models for Tertiary aquifer system 5.10.1 Factor analysis 5.10.2 Hierarchical Cluster Analysis 5.11 Hydrochemical impact of groundwater draft from Tertiary aquifers vi 5.12 Radioactivity of groundwater CHAPTER 6: HYDROCHEMICAL FACIES AND EVOLUTION OF 179-200 GROUNDWATER S 6.1 Introduction 6.2 Hydrochemical facies 6.2.1 Phreatic aquifer system 6.2.2 Confined aquifers of Recent alluvium 6.2.3 Tertiary aquifers 6.3 Inferences from Ion ratio studies 6.4 Characterization of hydrochemical processes 6.4.1 Salinisation mechanism and evolution of groundwater 6.4.2 Radioactive Isotopes ( 3H and 14 C) 6.5 Evolution of groundwater in different aquifer systems CHAPTER 7: SUMMARY AND CONCLUSIONS 201-206 REFERENCES 207-227 vii LIST OF TABLES No DESCRIPTION Page no. 1.1 Land use over the years in the Kuttanad area. 16 1.2 Normal monthly rainfall in the study area 19 1.3 Statistical analysis of annual rainfall data 20 2.1 Stratigraphic sequences in Kuttand 29 2.2 The details of bore wells in Kuttanad area used in the present study 35 The Top and bottom boundaries and thickness of geological formations in 2.3 39 different stratigraphic sequences derived from bore well data 2.4 Depth of occurrence of granular zones with high gamma count 53 Locations of observation wells and water levels in phreatic aquifer during pre- 4.1 73 monsoon and post-monsoon seasons. Hydrogeological details of tube wells in the area used for water level 4.2 74 monitoring in Recent confined aquifer. 4.3 Water level fluctuations in phreatic aquifer during April and Nov.2009 77 Trend of pre- and post-monsoon water levels in the phreatic aquifer for the 4.4 79 period from 2004 to 2013 Average monthly water level variations in phreatic aquifer for the period 2004- 4.5 82 2013 4.6 The piezometric heads in the Recent-confined aquifer system.