Status of the saltwater intrusion in Jaffna, Sri Lanka

Abstract

The objective of this study is to assess the present status of saltwater intrusion in the proximity of lagoons (Vadamarachchi and Uppuaru) in Jaffna, Sri Lanka. Ten villages along the periphery of the said lagoons were selected for a questionnaire survey (n=150) and groundwater quality analysis. The results revealed that the villages; Thondaimanaru, Atchuveli, Ariyalai, Kaithady and Karanavai are less affected (<33%) whilst Chemmani, Madduvil, Navatkuli, Irupalai and Neerveli are highly affected (>60%) in terms of intolerable level of salt content in the sandy aquifer. In Irupalai alone, more than 80% of the wells are highly affected where more than 80% of the wells monitored are exceeded the tolerable limits of EC (>2.5 S/cm) and salinity (>900 ppm), thus unsuitable for human consumption. The field mapping of water quality parameters (EC and salinity) revealed that the villages influenced by Vadamarachchi lagoon was lesser affected (<33%) than the villages influenced by Uppuaru lagoon. There is a trend of decreasing salinity from boarder of the lagoons to inland. As an initiative, water quality monitoring, establishing monitoring wells, and educating the people about adverse effects of over pumping of water are essential to reduce the saltwater intrusion in the area. Renovation of existing saltwater barrages would be an appropriate solution to enhance the groundwater quality in future.