Groundwater Management: Jaffna/ Sri Lanka                                            Herath Manthrithilake            Wate...
Jaffna Peninsula Water for a food-secure world         www.iwmi.org
Main Groundwater Aquifers in              Jaffna Peninsula        Chunnakam                      VadamaradchiKayts        ...
Annual average rainfall is 1250 mm, but 900 mm is    received between months of October and                   December    ...
Geology and condition of groundwater                         in the Jaffna Peninsula                 permeability         ...
• Spatial variation of net groundwater  recharge was observed to be in the range  of 12 to 69% of the total rainfall,• wit...
Water for a food-secure world        www.iwmi.org
PROBLEMS ASSOCIATED WITH AVAILABLE WATER                                    Over extractionQUANTITY                       ...
• Abstraction for irrigation varied from 9.4 to  15.7 mm/day with an average of 11.5  mm/day• Daily ET in 2011 varied from...
Monthly deficits (i.e., Rainfall - ET) for 2011           Water for a food-secure world                   www.iwmi.org
• Excessive irrigation was 51% over the peak  demand of 5.6 mm/day; the major portion of  which will eventually return to ...
Water for a food-secure world        www.iwmi.org
Fertilizer useCrop      Avg. nitrogen      Recommended             Excess          Applied (kg/ha)    nitrogen (kg/ ha)   ...
Concentration of nitrate- N during January 2011             Max PerD   D+H      Public      Paddy Banana         Highland ...
Water for a food-secure world        www.iwmi.org
Water for a food-secure world        www.iwmi.org
Agro-well densityWater for a food-secure world        www.iwmi.org
Hot-spots where agro-well density is very high             Water for a food-secure world                     www.iwmi.org
Water for a food-secure world        www.iwmi.org
Water for a food-secure world        www.iwmi.org
Roof top Count Water for a food-secure world         www.iwmi.org
ResultsWater for a food-secure world        www.iwmi.org
Challenges•   Establishing caps on abstraction•   Prevention of Contamination•   Prevention of over irrigation•   Increasi...
Recommendations•   Awareness creation•   Promotion of technologies•   Investment on pollution control•   Agrochemical use ...
Water for a food-secure world        www.iwmi.org
“There is a sufficiency in the world forman’s need but not for man’s greed.”
Groundwater management: Jaffna, Sri Lanka
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Groundwater management: Jaffna, Sri Lanka

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A presentation by Herath Manthrithilake at the Annual Research Meeting at IWMI HQ, Sri Lanka. December 2012.

Groundwater management: Jaffna, Sri Lanka

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  • Source agriculture produce
  • Groundwater management: Jaffna, Sri Lanka

    1. 1. Groundwater Management: Jaffna/ Sri Lanka Herath Manthrithilake Water for a food-secure world www.iwmi.org
    2. 2. Jaffna Peninsula Water for a food-secure world www.iwmi.org
    3. 3. Main Groundwater Aquifers in Jaffna Peninsula Chunnakam VadamaradchiKayts Thenmaradchi Water for a food-secure world www.iwmi.org
    4. 4. Annual average rainfall is 1250 mm, but 900 mm is received between months of October and December • 50% of the northeast monsoonal rainfall is received within a very short time period • 75% probability of rainfall in this district was 510 millimeters (mm) in Maha and 102 mm in Yala • Evaporation of 45-48% of the annual rainfall Water for a food-secure world www.iwmi.org
    5. 5. Geology and condition of groundwater in the Jaffna Peninsula permeability hydraulic conductivity Infiltration high to very high 30 to 50 m/d 430 mm/hourSource: Sirimanne 1952(a) Red earth, (b) Jaffna limestone, (c) Granitic genesis, MSL (mean sea level), GWT (groundwater level), FWZ (zone of freshwater saturation), BWZ (probable zone of brackish water);(1) dry well, (2) bottomless well or tidal well (Nilavarai), (3) ordinary successful well, (4) spring of Keerimalai type, (5) solution cavern. Water for a food-secure world www.iwmi.org
    6. 6. • Spatial variation of net groundwater recharge was observed to be in the range of 12 to 69% of the total rainfall,• with an average of 37% during the short rainy season (i.e., during October, November and December).• A significant volumes of run-off (43 - 60%)is lost to the sea during monsoon months.
    7. 7. Water for a food-secure world www.iwmi.org
    8. 8. PROBLEMS ASSOCIATED WITH AVAILABLE WATER Over extractionQUANTITY Rapid rate of extraction Development of salinity Own propertyDigging of Deep wells Wet season water table Excess pumping Dry season water table Wet season lens Excess Dry season lens pumping msl msl Fresh water Salt water Salt water intrusion Water for a food-secure world Salt water up coning www.iwmi.org (Ref. Prof.Y.D. Joshuva)
    9. 9. • Abstraction for irrigation varied from 9.4 to 15.7 mm/day with an average of 11.5 mm/day• Daily ET in 2011 varied from 3.4 mm/day in December to 5.6 mm/day in May with an annual average of 4.7 mm/day Water for a food-secure world www.iwmi.org
    10. 10. Monthly deficits (i.e., Rainfall - ET) for 2011 Water for a food-secure world www.iwmi.org
    11. 11. • Excessive irrigation was 51% over the peak demand of 5.6 mm/day; the major portion of which will eventually return to groundwater• This limits the water availability and promotes saltwater intrusion• Have serious consequences on groundwater pollution as the return flow could carry fertilizer and pesticide residues Water for a food-secure world www.iwmi.org
    12. 12. Water for a food-secure world www.iwmi.org
    13. 13. Fertilizer useCrop Avg. nitrogen Recommended Excess Applied (kg/ha) nitrogen (kg/ ha) nitrogen (kg/ha)Onion 178.1 70 108.1Carrot 230 150 80.0Cabbage 142.6 150 -7.4Beetroot 246 180 66.0Tobacco 262.9 No recommendation - Water for a food-secure world www.iwmi.org
    14. 14. Concentration of nitrate- N during January 2011 Max PerD D+H Public Paddy Banana Highland crops Farm Water for a food-secure world www.iwmi.org
    15. 15. Water for a food-secure world www.iwmi.org
    16. 16. Water for a food-secure world www.iwmi.org
    17. 17. Agro-well densityWater for a food-secure world www.iwmi.org
    18. 18. Hot-spots where agro-well density is very high Water for a food-secure world www.iwmi.org
    19. 19. Water for a food-secure world www.iwmi.org
    20. 20. Water for a food-secure world www.iwmi.org
    21. 21. Roof top Count Water for a food-secure world www.iwmi.org
    22. 22. ResultsWater for a food-secure world www.iwmi.org
    23. 23. Challenges• Establishing caps on abstraction• Prevention of Contamination• Prevention of over irrigation• Increasing recharge & runoff reduction• CC challenges• Stakeholder cooperation Water for a food-secure world www.iwmi.org
    24. 24. Recommendations• Awareness creation• Promotion of technologies• Investment on pollution control• Agrochemical use reduction• Rainwater harvesting & recharge• A policy framework for GW mgt. Water for a food-secure world www.iwmi.org
    25. 25. Water for a food-secure world www.iwmi.org
    26. 26. “There is a sufficiency in the world forman’s need but not for man’s greed.”

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