Coastal Aquifer System, Kerala
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क� द्र�यू�म भ जल बोड셍 जल संसाधन, नद� �वकास और गंगा संर�ण मंत्रालय भारत सरकार Central Ground Water Board Ministry of Water Resources, River Development and Ganga Rejuvenation Government of India Report on MAPPING AND AQUIFER MANAGEMENT PLAN Coastal Aquifer System, Kerala के र ल �ेत्र, �त्रवेꅍ饍गम Kerala Region, Thiruvananthapuram भारत सरकार GOVERNMENT OF INDIA जल संसाधन, नद� �वकास और गंगा संर�ण मंत्राल MINISTRY OF WATER RESOURCES, RIVER DEVELOPMENT & GANGA REJUVENATION केꅍद्र�य भू�मजल बोड셍 CENTRAL GROUND WATER BOARD MAPPING AND MANAGEMENT PLAN OF THE COASTAL AQUIFER SYSTEM OF KERALA के र ल �ेत्र KERALA REGION �त셁वनꅍतपुरम THIRUVANANTHAPURAM OCTOBER 2016 PREFACE The State of Kerala, located in the South-western tip of India, accounts for only 1.2 percent of its geographical area but is home to about 3 percent of its population. Although bestowed with copious average annual rainfall of more than 3000 mm and also endowed with large surface water resources, only a small portion of the available resources is being utilized. To overcome the paradoxical situation, a proper understanding of the disposition, extents, characteristics, status of resource and quality aspects of the water-bearing formations, is required to ensure judicious and planned utilization of this precious natural resource and its long-term sustainability. Detailed aquifer mapping studies in Kerala State were taken up with this objective, prioritizing study of the Over exploited and Critical blocks along with Coastal aquifers during the Twelfth plan. The report titled “Mapping and management plan of the Coastal aquifer system of Kerala’’gives a complete and detailed scientific account of the various aspects of the coastal aquifer system in Kerala stretching including its vertical and horizontal dimensions, flow directions, quantum and quality of the resources, of both - the shallow and deeper zones of the coastal aquifers. Voluminous data were generated consequent to hydrogeological studies, ground water regime monitoring studies, exploratory drilling, geophysical studies etc carried out in the area, are incorporated in the report. The information is further supplemented by documenting all the relevant available data collected from concerned state department. It portrays the various ground water issues pertaining to the area. Thus it provides a total and holistic solution to the water security problems in the coastal aquifers of the state. This document has been prepared under the guidance of Dr. N.Vinayachandran,Scientist D & Nodal Officer, National Aquifer Mapping Studies in Kerala, Central Ground Water Board. The data compilation work is accomplished through the sincere and painstaking efforts of Smt Rani V.R., Scientist C, Sh Santana Subramani, Scientist C, Sh C Rajkumar, Scientist C, Sh.S.Singathurai, Scientist B, Sh Vijesh, Scientist B, Sh Sreehari S, Assistant Hydrogeologist, Dr. S.Shakti Murugan, Assistant Hydrogeologist, of the Central Ground Water Board, Kerala Region, Trivandrum. I take this opportunity to thank all of them for their help and cooperation in the preparation of this report. I am also thankful to the Chairman, Members and officers of CGWB, Faridabad for their valuable guidance in finalizing this document. Thanks are also due to various organizations of Government of Kerala and Government of India for providing data required for the compilation of this document. I hope this compilation will be of help to the planners, administrators and stakeholders in the water sector in Kerala and will serve as a useful guide for the optimal and sustainable management of limited ground water resources in Coastal aquifer systems. Trivandrum October 2016 (V.Kunhambu) Regional Director Contents 1.0 INTRODUCTION ............................................................................................................................1 1.1 Objectives ............................................................................................................................................ 1 1.2 Scope of the study ............................................................................................................................... 1 1.3 About the area .................................................................................................................................... 2 1.4 Geomorphology ................................................................................................................................. 2 1.5 Drainage .............................................................................................................................................. 3 1.6 Climate and rainfall ............................................................................................................................. 4 1.7 Soil ....................................................................................................................................................... 4 1.8 Agriculture and Irrigation .................................................................................................................... 6 1.9 Geology .............................................................................................................................................. 7 2.0 DATA COLLECTION, GENERATION AND INTEGRATION .................................................................. 12 2.1 Phreatic aquifer system .................................................................................................................... 12 2.2 Tertiary aquifer system ..................................................................................................................... 13 3.0 DATA INTERPRETATION AND AQUIFER MAPPING ....................................................................... 14 3.1 Aquifer geometry .............................................................................................................................. 14 3.2 Composite lithologs and VES............................................................................................................. 15 3.3 Soil Infiltration Studies ...................................................................................................................... 19 3.4. Phreatic aquifers: ............................................................................................................................. 20 3.5. Deep confined aquifers .................................................................................................................... 25 3.6. Warkalai beds ................................................................................................................................... 29 3.7 Quilon beds ....................................................................................................................................... 31 3.8 Vaikom beds ...................................................................................................................................... 31 4. 0 HYDROCHEMISTRY .................................................................................................................... 38 4.1. Shallow ground water ...................................................................................................................... 38 4.2. Hydrochemistry of the Tertiary aquifers .......................................................................................... 38 4.3 Characterization of hydrochemical processes .................................................................................. 42 5.0 GROUND WATER RESOURCES ..................................................................................................... 48 5.1 Shallow phreatic aquifer ................................................................................................................... 48 5.2. Deeper confined aquifers ................................................................................................................. 49 5.3 Gound Water Resource of Warkalai and Vaikom Aquifer (Based on SIDA Project) ......................... 54 6.0 GROUND WATER RELATED ISSUES .............................................................................................. 55 7.0 GROUND WATER MANAGEMENT PLAN ....................................................................................... 57 7.2 Water Conservation and Artificial Recharge ..................................................................................... 58 LIST OF FIGURES Fig. 1.1 The Northern (N), Central (C), and Southern (S) parts of the area .................................................. 2 Fig 1.2: Geomorphology of the area ............................................................................................................ 3 Fig 1.3. Soil types in the area ........................................................................................................................ 6 Fig 1.4: Tectonic map of Kerala coast and off shore (Prasada Rao,1984)..................................................... 9 Fig 3.1: The geological sections along the coast between Anjengo and Pariyapuram ............................... 14 Fig. 3.2 Panel diagram showing aquifer disposition in Kuttanad alluvium ................................................. 15 Fig.3.3 Composite logs of Lithology, SP, Resistivity and Natural Gamma ................................................... 16 Fig.3.4. Composite logs of lithology, SP, Resistivity and Natural Gamma .................................................. 16 Fig.3.5 Hydrographs of dug wells in the