Status of the saltwater intrusion in Jaffna, Sri Lanka

S Uthayashangar,S Devaisy,A Nanthakumaran

doi:10.4038/cjs.v48i3.7647

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 ( 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 the future.

Highlights

The Jaffna Peninsula, lies in the longitude and lattitude79 0 45’ N – 9 0 30’ E and 80 0 20’ N - 9 0 50’ E and covers the extent of 1000 km2 forms the northern edge of Sri Lanka
This study reveals that all the villages sampled have saltwater intrusion effect despite the percentage of wells are affected
The village Irupalai is the highly affected village where 80% of wells are with intolerable levels of salt content whilst Thodaimanaru is the least affected village in which less than 33% of wells are with intolerable salt content

Summary

Introduction

The Jaffna Peninsula, lies in the longitude and lattitude79 0 45’ N – 9 0 30’ E and 80 0 20’ N - 9 0 50’ E and covers the extent of 1000 km forms the northern edge of Sri Lanka. Salt water intrusion is a serious issue in the coastal zone wells of Jaffna, since the wells are producing low quality groundwater unsuitable for drinking and agricultural purposes (Rink et al, 2016). This eventually left hundreds of acres of arable lands abandoned and caused hundreds of wells with brackish water in the coastal zone (Kumara et al, 2013; Sivakumar, 2013). The limestone aquifer together with thin sand layer provides a source of drinking water for the peninsula. Rainfall is the only source that replenishes the limestone aquifer (Mikunthan et al, 2013)

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Conclusion