Ground Water Year Book of Kerala (2018-19) TECHNICAL REPORT SERIES GOVERNMENT OF INDIA MINISTRY OF JALSHAKTI CENTRAL GROUND WATER BOARD GROUND WATER YEAR BOOK OF KERALA (2018-2019) KERALA REGION THIRUVANANTHAPURAM SEPTEMBER 2019 Ground Water Year Book of Kerala (2018-19) GROUND WATER YEAR BOOK OF KERALA (2018-2019) Table of Contents 1. Introduction ........................................................................................................................... 1 2. Hydrogeology......................................................................................................................... 4 2.1 Physiography…………………………….. ............................................................................. 4 2.2 Geology…………………………….. .................................................................................... 4 2.3 Occurrence of Groundwater…………. .................................................................................. 5 3. Rainfall distribution in Kerala during 2018-19 .................................................................... 7 3.1 Introduction…………………….. .......................................................................................... 7 3.2 Annual rainfall distribution…………..................................................................................... 7 3.3 Monthly rainfall distribution… .............................................................................................. 7 3.4 Normal rainfall vs. actual rainfall........................................................................................... 7 3.4.1 Summer period……………………………………………………………………………….8 3.4.2 South-west monsoon period………………………………………………………………….8 3.4.3 North-east monsoon period………………………………………………………………… 8 3.4.4 Winter period………………………………………………………………………………...8 3.5 Seasonal rainfall contribution to the total rainfall of the year 2018-19……............................. 9 3.6 Comparison of 2018-19 rainfall with previous year rainfall .................................................... 9 3.6.1 Summer season………………………………………………………………………………9 3.6.2 Southwest monsoon season…………………………………………………………………10 3.6.3 Northeast monsoon season………………………………………………………………….10 3.6.4 Winter season……………………………………………………………………………… 10 4. Depth to water level scenario during 2018-19.................................................................... 20 4.1 Depth to water level during April 2018 ................................................................................ 20 4.2 Depth to water level during August 2018 ............................................................................. 21 4.3 Depth to water level during November 2018 ........................................................................ 21 4.4 Depth to water level during January 2019 ............................................................................ 22 5. Water level fluctuation in kerala during 2018-2019 ........................................................... 30 5.1 Fluctuation between April 2018 and August 2018 ................................................................ 30 5.2 Fluctuation between April 2018 and November 2018 ........................................................... 30 5.3 Fluctuation between April 2018 and January 2019 ............................................................... 31 6. Comparison of 2018-19 water levels with the decadal mean (2008-2017) .......................... 38 6.1 Fluctuation between Mean April (2008-2017) and April 2018 .............................................. 38 6.2 Fluctuation between Mean August (2008-2017) and August 2018 ........................................ 38 6.3 Fluctuation between Mean November (2005-2014) and November 2015 .............................. 39 6.4 Fluctuation between Mean January (2009-2018) and January 2019 ...................................... 39 7. Long term ground water level trend ................................................................................... 48 8. Behaviour of piezometric heads in deep aquifers of confined/semiconfined nature during the year 2018-2019................................................................................................................... 56 8.1 Sedimentary area………………… ...................................................................................... 56 8.2 Crystalline Area…………….. ............................................................................................. 56 9. Hydrochemistry .................................................................................................................. 59 9.1 Introduction…………………. ............................................................................................. 59 9.2 Water Quality Monitoring…….. .......................................................................................... 59 9.3 Methods and Methodology……. .......................................................................................... 60 10. Sum Up ............................................................................................................................ 68 Ground Water Year Book of Kerala (2018-19) List of Tables Table 1.1: District wise breakup of GWMWs in Kerala State as on 31-03-2019 ................................ 2 Table 2.1: Regional Geological Setting of Kerala ............................................................................ 5 Table 3: Monthly Rainfall Distribution during 2018-19, mm ...........................................................13 Table 3.2: Seasonal Rainfall, Normal Rainfall and the percentage Departure in 2018-19 in Kerala State ................................................................................................................................................14 Table 3.3: Seasonal Rainfall Distribution and their Percentage Contribution to Annual Rainfall (2018-19) ........................................................................................................................................15 Table 3.4:Comparison of 2018-19 Seasonal Rainfall with the Previous Year Seasonal Rainfall of 2017-18...........................................................................................................................................16 Table 4.1: District Wise Well Frequency For Different Ranges Of Depth To Water Level For April 2018 ......................................................................................................................................25 Table 4.2: District Wise Well Frequency for Different Ranges of Depth to Water Level for August 2018 ....................................................................................................................................26 Table 4.3: District Wise Well Frequency for Different Ranges of Depth to Water Level for November 2018...............................................................................................................................28 Table 4.4: District Wise Well Frequency for Different Ranges of Depth to Water Level for January 2019 ...................................................................................................................................29 Table 5.1: District wise – Water Level Fluctuation and Frequency Distribution for Different Ranges from April 2018 – August 2018 ...........................................................................................35 Table 5.2: District wise – Water Level Fluctuation and Frequency Distribution for Different Ranges from April 2018 – November 2018......................................................................................36 Table 5.3: District wise – Water Level Fluctuation and Frequency Distribution for Different Ranges from April 2018 - January 2019 ..........................................................................................37 Table 6.1: District wise – Water Level Fluctuation with Mean and April 2018 (April 2018 – Mean (April 2008-2017)) ..........................................................................................................................44 Table 6.2: District wise – Water Level Fluctuation and Frequency distribution for different range between Decadal Mean (August 2008-2017) and August 2018 ........................................................45 Table 6.3: District wise – Water Level Fluctuation with Mean and November 2018 (November 2018 – Mean (November 2008-2017)) .............................................................................................46 Table 6.4: District wise – Water Level Fluctuation and frequency distribution for different ranges from January 2019 -decadal mean (January 2009-2018)........................................................47 Table 9.1: Analytical method of the parameters analysed in CGWB, KR Laboratory .......................60 Table 9.2: The range of chemical parameters in the study area of CGWB –KR Region ....................61 Table 9.3: Showing Wells having EC > 2000 µS/cm at 250C ...........................................................62 Table 9.4: Frequency Distribution of Electrical Conductivity in Ground Water Monitoring Wells in Kerala State .................................................................................................................................62 Table 9.5: District wise Frequency Distribution of Electrical Conductivity in GWMWs ...................63 Table 9.6: Locations showing the Fluoride concentration .................................................................65 higher than BIS limit (>1.0mg/L) ....................................................................................................65