Status of a Tsunami affected coastal aquifer along the East Coast of Sri Lanka

Highly productive unconfined aquifers with transmissibility of around 2500m2/day, and electrical conductivities around 200 μS/cm where static water level is of about 2.5 m in the east coast of Sri Lanka are affected by the tsunami on December, 2004. A hydro geological and geophysical survey carried out 10 months later, in the Batticaloa District, shows a gradual lateral and downward movement of saline water plume towards the sea and the lagoon. In addition, the slow vertical sinking of the highest saline zone of the plume has reached a depth of about 20 m at present. The water quality of the uppermost horizons of the aquifer is recovering slowly. Spatial distribution of Electrical conductivity of the dug well water too, indicates the lateral retrieval of saline water front towards the sea. It is expected that infiltration of precipitation of the oncoming monsoon rains will further improve the quality of water.