Thursday 25 August 2005

P3

PTH0109
Assessment of the status of the ground water resource after the tsunami impact in the coastal tract of SE coast of India
Alagappan, Ramanathan¹, Ashoak K, Keshari², Sabarthinam, Chidhambaram³
1 Jawaharlal Nehru University, India
2 Indian Institute of Technology, India
3 Annamalai University, India
Author email: alr0400@mail.jnu.ac.in
The ground water in the tsunami affected coastal belt of Tamilnadu shows various degree of impacts on the groundwater resources (salinization and loss of fresh water , sea water fresh water interface migration, partial pollution due to sea water inundation) . In affected areas, the main sources of drinking water are ponds and dug wells. These sources are contaminated due to mixing of seawater, leading to the scarcity of drinking water. The groundwater near the coastal area (up to approx 500m) has become highly saline and salinity has increased 10 to100 fold and the open wells are completely overwhelmed. The ground water levels were monitored and sampled before and after tsunami (twice) in the 600km coastal areas. Data's indicate that there is a overall marginal variation in pH, EC , sulphate and bicarbonate in these areas. Dissolved metals and the nutrients show significant increase in certain urban zone. Our observation indicate that where ever the saline water get stagnated for longer time are more affected by salinity than the area which are just inundated and are not holding saline waters in their depressions .The Agricultural activities seem to be enhancing the Nitrates and phosphate to this ground waters. The ground water data after tsunami show that the ground water quality has improved further in the affected areas after frequent pumping in the regions by the villagers. The water level in most of the areas shows slight increase after tsunami with deterioration in water quality further. The analysis of the second batch samples after tsunami will be completed in a month or so and we will be able to get clearer picture of Tsunami impact to these coastal ground waters. we have identified some ground water resources for drinking water supply in the emergency situation like tsunami in future.

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