Water for a food-secure world Sustaining a limestone aquifer: Case of Jaffna Peninsula in Sri Lanka A.Sutharsiny H. Manthrithilake International Water Management Institute Water for a food-secure world Vadamaradchi aquifer Thenmaradchi aquifer Kayts aquifer Chunnakam aquifer Type of Aquifer in Jaffna Peninsula Water for a food-secure world This paper explores the major groundwater quality issues, related reasons for contamination and resulting health issues, based on published research articles. Based on this review, the paper proposes few recommendations to ensure sustainability and safe use of the groundwater resources in Jaffna. Water for a food-secure world Source: 2002 to 2011 : Jaffna district statistical hand book Average monthly rainfall derived from year 2002 to 2011 Source: 2002 to 2011 : Jaffna district statistical hand book Water for a food-secure world Water for a food-secure world 1952: Specific Yields of limestone aquifer Kayts 0.8 gph/sq.ft Chunnakam 8 gph/sq.ft (Sirimanne, 1952) 1955: Pumping test safe rate of pumping 2,400 g/h in the Thenmaradichy area, 20,000 g/h in Thirunevelly & 35,000 g/h in the Puttur area (Sirimanne, 1955) : Groundwater balance studies (Arumugam,1970) 1994: losses by direct runoff (about %), and losses by evaporation (about %), % of the rainfall is left over for ground water recharge (Navaratnarajah, 1994) 2006: Feasibility study - recommended groundwater extraction rate Valikamam is 14,400m 3 /d, Vadamaradchi is 6,000m 3 /d, and Point Pedro is 4,000m 3 /d (Feasibility report, 2006) Some quantitative studies in the Jaffna Peninsula Water for a food-secure world ISSUE 1: Number of agro-wells on the rise 1968: agricultural wells: up to 75 wells /100 ha domestic wells: 380 wells /100 ha (Balendran et al., 1968) 2002: Jaffna Rehabilitation Project (JRP) - over 100,000 dug wells in the Peninsula - 17,860 are agro wells & the remainder is used to domestic & home garden purpose(Kraft, 2002) 2011:Agro wells counting(IWMI study, 2011) Water for a food-secure world Agro-well distribution in Jaffna District Identified agro-wells are 19,905 (excluding Delft Island) 1 Sq Km = 100 ha (IWMI study, 2011) Agro-well density Hot-spots where agro-well density is very high ISSUE 2: Salinity development (IWMI study, 2011) Water for a food-secure world Over Extraction from shallow and deep wells Zone of seasonal fluctuation of water table Fresh water lens Transition zone Saline water YearFindingsReference 1983Nitrate-N in the water and soils were above the WHO recommended level in Jaffna district Mageswaran & Mahalingam, High concentration (40 mg/l) in Jaffna Peninsula (Geochemical Atlas of Sri Lanka) Dissanayake, C.B. & Weerasooriya, Concentration in farm and domestic wells were 79 % greater than WHO in Jaffna and Kilinochchi districts Nagarajah et. al., /1998Large numbers of wells exceed the WHO standard in Valikamam area Rajasooriyar et al., /2002Nitrate value in the range of mg/l in Jaffna districtMageswaran, /2008range of 10-15mg/l within the intensively cultivated area in some part of Valikamam area Mikunthan & De Silva, Nitrate-N level is ranging from 0.0 to 15.5 mg/lHidayathulla & Karunaratna, 2013 ISSUE 3: Nitrate Contamination on groundwater Water for a food-secure world Nitrate N in water supply wells over the period of 30 years (mg/l) ???? Water for a food-secure world Water for a food-secure world Agriculture Water for a food-secure world Crop Crop water requirement Irrigation by farmers (mm/day) Excess irrigation (mm/day) (%) Banana Cabbage Cassava Onion Tobacco Excess irrigation for each crop in studied area (IWMI study, 2011) Water for a food-secure world Excess amount of nitrogen application for each crop Crop Avg. nitrogen applied (kg/ha) Recommended nitrogen (kg/ ha) Excess nitrogen (kg/ha) Onion Carrot Cabbage Beetroot Tobacco262.9No recommendation - (IWMI study, 2011) Water for a food-secure world 80% of the wells were affected due to mixing up of abundant nitrogenous waste matter (Gunasekaram, 1983) Normal coliforms showed that water from Passaiyoor, Kurunagar, Koddady and Navanthurai areas cannot be used for either drinking or domestic purposes (Mageswaran, 2003) The tap water analysis at Kayts, Gurunagar and the supply from Kondavil well: contaminated with fecal coliforms on E- Coli bacteria (GTZ-JRP /2002) ISSUE 4: Bacterial Contamination on groundwater Water for a food-secure world Reasons.. The major soils in the Peninsula are the calcic red-yellow latosols which are shallow, fine textured and well-drained with very rapid infiltration rate(De Alwis and Panabokke, 1972) - filtration and removal of micro-organisms within the unsaturated zone is not effective - limestone itself, almost there is no purification capacity Pollutants are spreading far and wide Water for a food-secure world Accessibility to safe latrine by MOH area Inadequate access to safe latrines % (RDHS statistics-2012) Inadequate distance between pit latrines and dug wells Indiscriminate disposal of garbage and infective hospital waste The open dumping yards for waste disposal Poor hygiene practices related to drinking water Water for a food-secure world Distance between pit latrines and dug wells for two regions in the Jaffna Peninsula (Rajasooriyar et al., 2002) Distance between pit latrines and dug wells for two regions in the Jaffna Peninsula Water for a food-secure world Open dumping yard at Kallundai Water for a food-secure world By Bacterial Pollution Water and food borne diseases: Typhoid, Cholera, infective hepatitis, diarrhea, and worm infestation By Chemical pollution Work carried out in , Northern Province - had the highest incidence of cancer in Sri Lanka - the incidence of esophageal cancer was double WHO : more than 10mg/L NO 3 -- N: Blue babies - no recorded cases as yet from the Teaching hospital - a high risk of nitrate toxicity could lead to this ISSUE 4: Under Threat not only Environment, but Human Health, too Water for a food-secure world High incidence of cancer ( ) could be partly attributed to the high nitrate content in water (Panabokke, 1984) Several studies came up with warnings on the risk of esophagus cancer and stomach cancer due to consumption of well water with higher nitrate - N concentration than the recommended level by WHO (Kraft, 2002) (Sivarajah,2003) (Gunalan et al., 2011) high amounts of calcium and phosphate in the drinking water may accelerate stone formation in the bladder Water for a food-secure world CONCLUSION Over 50% of the recharged water is lost to sea while in some parts of the Peninsula; saltwater is getting into fresh water aquifers due to over extraction. Excessive use of fertilizer, agro-chemicals, and improper waste disposal together with excessive irrigation is causing the nitrate- N concentration in groundwater. Hence, the management of all these activities is critical to safeguard human health, livelihoods and environment. Water for a food-secure world What s to be done ! Installing meteorological station To increase the groundwater recharge Regulate well construction and abstraction Minimize the Risk of Sea Water Intrusion Efficient irrigation water management Reduce intrusion of Chemical into Groundwater: Improve the Wastewater and Fecal Management Improve the Solid Waste Management Public Awareness for Groundwater: Empower Regulatory Committees Capacity building in Water Boards, CEA and related Agencies Water for a food-secure world THANK YOU