An Integrated Study on the Holocene Aquifer and the Water Resource Potential of Karamana River Basin, Southern Kerala, India
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AN INTEGRATED STUDY ON THE HOLOCENE AQUIFER AND THE WATER RESOURCE POTENTIAL OF KARAMANA RIVER BASIN, SOUTHERN KERALA, INDIA Thesis submitted to the COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Marine Geology Under the Faculty of Marine Sciences By SAKKIR S. Department of Marine Geology and Geophysics School of Marine Sciences Cochin University of Science and Technology Kochi 682016 December 2014 Dedicated to my Respected Parents DECLARATION I hereby declare that the thesis entitled “An Integrated Study on the Holocene Aquifer and the Water Resources Potential of Karamana River Basin, Southern Kerala, India” is an authentic record of the research work carried out by me under the supervision and guidance of Prof. Dr. K. Sajan, Professor in charge of Head, Department of Marine Geology and Geophysics under the Faculty of Marine Sciences, Cochin University of Science and Technology and also that no part thereof has been presented for the award of any degree in any University/ Institute. Kochi- 16 Sakkir S. 06-12-2014 CERTIFICATE This is to certify that the thesis entitled “An Integrated Study on the Holocene Aquifer and the Water Resource Potential of Karamana River Basin, Southern Kerala, India” is an authentic record of research work carried out by Mr. Sakkir S, under my supervision and guidance in partial fulfillment of the requirement of the degree of Doctor of Philosophy in the Department of Marine Geology and Geophysics, Cochin University of Science and Technology, under the Faculty of Marine Sciences and also that no part thereof has been presented for the award of any degree or diploma in any other University / Institute. Kochi – 16 Prof. Dr. K. Sajan 06-12-2014 (Research Supervisor) Department of Marine Geology and Geophysics Cochin University of Science and Technology Kochi, 682016 ACKNOWLEDGMENT At the outset, I would take this opportunity to express my sincere thanks to my supervisor and guide Prof. (Dr) K. Sajan, Head in charge, Department of Marine Geology and Geophysics, School of Marine Sciences, Cochin University of Science and Technology (CUSAT) for providing guidance at all stages, for carrying out my research to its final stage. My sincere thanks also goes to the Director, School of Marine Sciences for permitting me to do this work as part - time research scholar. My thanks also go to all members of the teaching and non-teaching staff for whatever assistance I have received, at various stages of this research work. I have great pleasure in recording my sincere gratitude to my learned Prof S. Mohankumar, former Head, Department of Geology, University of Kerala, Dr. Reji Srinivas, Scientist, NCESS, Thiruvananthapuram, Dr. Baiju K,R., Dr.P.Ajayakumar, Dr.N.R. Nisha (Assistant Professors) and Harisanth S (Research Scholar), Cochin University of Science & Technology. I take great pleasure to express my heartfelt gratitude to my former professor and head Dr. Prasanna kumar, Dept of Geology, University of Kerala and Mr. Praphakumar DMG, Gopakumar, District Geologist, Department of Mining and Geology Govt. of Kerala, Dr. Girish Gopinath Scientist, CWRDM and Dr. Ajith G. Nair, Assistant Professor, CET, Trivandrum, Chettachhal Sahadevan, Chairman, Nedumangad Munucipality, M. Narayana Pillai, Private Secretary Minister for Power, Secretariat, Govt of Kerala. They took keen interest and gave valuable advice, constant encouragement and timely advice then and there which were immense help to complete this work., Last but not the least I express my sincere love to my family members for their continuous inspiration and help reentered to me. Sakkir S. PREFACE Water constitutes the basic resource for life. Management of coastal aquifers, which are the important sources of freshwater that feed the rapid economic growth of the region is facing increasing challenges. A large portion of the global population inhabits the coastal and adjoining areas leading to a high demand for water both surface and ground water resources of coastal tracts. With increasing population this puts significant stress on water resources of many of the coastal tracts of the world. Several recent studies have indicated that coastal aquifers of Cenozoic age are globally under threat due to several reasons. Climate change is expected to affect the freshwater resources of coastal aquifers, which in turn will affect half of the global population residing in coastal areas. Sea-level rise will induce landward migration of the freshwater-saltwater transition zone, i.e., seawater or saltwater intrusion, jeopardizing freshwater availability. In order to facilitate the management of fresh coastal groundwater resources, a comprehensive understanding of the SLR-SWI relationship is crucial. Coastal aquifer of Karamana River Basin and its neighborhood is associated with older Pleistocene and younger Holocene sedimentary successions and the water resources of this region are predominantly used for domestic purposes and to a little extent for irrigation. No reliable long - term data are available regarding neither the quantity of water generated by the aquifer nor the possible changes of quality, except for the period roughly covering the last decade. Relatively dense habitat with significant population increase of the tract may result in overexploitation of water and also deterioration of quality of water over time. Hence the present study The Holocene aquifer of the Karamana River Basin (KRB) of the Thiruvananthapuram District, Kerala and its water resources potential form the main theme of the thesis. Emphasis has also been given to the hydrogeochemisty of the water resources and morphmetric analysis of the Karamana River Basin. The thesis is organized into 5 chapters. Chapter-I gives a general introduction of the Karamana River Basin which is a 6th order basin and spreads over an area of 703 km2. The river originates at Chemmunji Mottai Peak (1717 m amsl) and flows down across the highland, midland and lowland zones with two main tributaries Killi Ar and Todai Ar. Chapter-II deals with the Holocene geology of the KRB. A general picture of the Quaternary succession of the coastal tract of the basin is presented in this chapter. Quaternary sediments of Karamana River Basin are dominantly of coarse sand with occasional silty and clayey intercalations, the latter hardly exceeding 2% of the bulk and devoid of marine fossils indicating their fluvio- lacustrine origin. The radiocarbon analysis elucidates the Holocene succession of the Karajan Basin which commences upward from the middle litho unit and the underlying portion of the Quaternary constituting the Pleistocene succession of the region. The maximum thickness of the Holocene Stratigraphy units of the Karajan Basin is restricted to about 20m. The hydrological properties of the Holocene aquifer of the basin are also elaborated in this chapter. It is concluded that the specific yield of Holocene sediments of Karamana River Basin has been noted to range from 28 percent to 32 percent and its coefficient of storage ranges from 0.028 to 0.032 where as the transmissivity value range from 280 m2/day to 420 m2 /day and the coefficient of permeability (hydraulic conductivity) has been noted to be very high (25.5 m/day to 45.0 m/day). Chapter-III illustrates the salient features of the morphmetric attributes (such as the linear, areal and relief parameters) of Karamana River Basin. Karamana River Basin is dominantly dendritic in the lower reaches expressing its homogeneity of texture and lack of any significant structural control. Linear aspects of the basin and other morphometric characteristics like the total area (a), drainage density (Dd), constant of stream maintenance (C), stream segment frequency or channel frequency (F), drainage area of each order (A1 to A6), average density of each order (Ā1 to Ā6), area ratio (Ar), form factor (Rf), circularity ratio (Rc), elongation ratio (Re), basin shape factor (s), unit shape factor (Ru), form factor etc are presented in this chapter. Among the various relief features of the Karamana River Basin, basin relief (Rb), relief ratio (Rh), and ruggedness number (Rn) were measured/calculated. Chapter-IV encompasses the hydrochemistry and the drinking water potential of the basin. It is noted that the groundwater samples collected from urban area of Thiruvananthapuram exhibit notable regional and spatial variation in terms of physical, chemical and biological qualities. There is significant contamination of the Holocene aquifer of Karamana River Basin due to mixing of polluted waters from the canal. The hydrochemical analysis include pH, conductivity, TDS, alkalinity, hardness, chloride, sulphate, nitrate, phosphate, fluoride, sodium, potassium, calcium, magnesium, BOD, COD, total coli form and fecal coliform. Chapter-V summarizes the salient findings of the study. The literature perused and cited is given towards the end of the thesis under references. CONTENTS Page No Preface List of Figures List of Tables Chapter I. General Introduction 1.1 Introduction 1 1.2 Holocene aquifer 3 1.2.1 Holocene of Kerala 5 1.3 Morphometric Studies in India 13 1.3.1 Drainage Morphometric Studies in Kerala 14 1.4 Karamana River Basin-An Overview 15 1.4.1 Geographic setting of study area 16 1.5 Drainage -The Karamana River (Karamana Ar) 21 1.6 Topographic features of Karamana River Basin 24 1.7 Geologic setting of the study area 27 1.8 Climate 30 1.9 Soil types 33 1.10 Landuse Pattern 34 1.11 Environmental issues 37