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Natural remediation of Groundwater quality in tsunami affected
Coastal areas- Sri Lanka

Dr. Ranjana U K Piyadasa
Department of Geography, University of Colombo, Colombo, Srilanka
Dr. K.D.N Weerasinghe,  Dr. W.A.D.C.S. Weerasinghe
Dr. T.H.Y.Dharmasena, Dr. L.M.J.R Wijayawardhana
Department of Agriculture Engineering, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya - Srilanka
Dr. Janitha A Liyanage, Dr. K M Susantha C Kumara
Department of Chemistry, University of Kelaniya, Kelaniya, Srilanka

Asian Tsunami occurred in 26th of December 2004 had big impact to the southern Sri Lankan coastal strip of groundwater. Almost all the open dug wells of the affected zone were heavily damaged and groundwater resources were heavily polluted.The previous studies conducted in the southern coastal belt after the tsunami indicates that the groundwater electrical conductivity (EC) increased from 300 to 5000 and more micro siemens/ cm. The principle objective of the present research study is to identify the variation and natural remediation of ground water quality in Tsunami affected southern coastal belt. The study was conducted during 2005 May to 2007 November in coastal belt of southern Matara district, which has been seriously affected by the tsunami waves. The research study includes monitoring network of 90 dug wells distributed over the Tsunami-affected coastal belt and location of the wells was detected with a GPS. Continuous monitoring of the water levels in the wells were conducted in monthly interval during the study period, and the water quality observed in respect to electrical conductivity (EC), total dissolved solids (TDS),pH and salinity. Groundwater quality changers and hydro geological maps prepared using the GIS packages. The results conclude that atmospheric precipitations, hydrogeological condition, geomorphology of the area are the main natural remediation factor to change the quality of groundwater. During the monsoon periods, monthly rainfall exceed 400 micro siemens/ cm and groundwater in the elevated areas from the coastal line EC values are decreased due to groundwater recharge from inland areas. In the some areas where low hydraulic gradient of the groundwater, EC values are not change considerably and remain 2000 to 3000 micro siemens/ cm.


 

Application for Participation (PDF)