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Hydrogeological condition and groundwater quality distribution in the tsunami affected Southern coastal area of Sri Lanka
By Dewwanthi Karunarathna | February 28, 2008
Groundwater monitoring in the tsunami affected southern coastal Weligama bay area was conducted during May 2005 to July 2006 to determine the hydrogeological conditions and groundwater quality by selecting 90 dug wells where water level, electrical conductivity (EC), total dissolved solids (TDS) and pH was measured in monthly interval. The Weligama bay area is located in latitudes and longitudes of 80022’, 5097’. The dug wells are sunk into the permeable quaternary sand deposits in the coastal margin at Weligama Bay area is very permeable and hydro-geological conditions are very favorable for saltwater intrusion.
The study helped to prepare groundwater isograph map and the distribution of EC, TDS and pH maps using the GIS package MAPINFO. Groundwater isograph map help to identify groundwater distribution of the coastal area of Weligama. There exist a closed relationship between topographical map & groundwater contour map.
The results of the study revealed that the Electrical conductivity of well water in all wells situated in the Tsunami affected Zone are turned to be saline (EC in average increases from 1500 µ Siemens per cm to around 4000 µ siemens /cm.). According to the hydrographs prepared during the study period, unconfined quaternary aquifer ground water level intimately related to atmospheric precipitation. The characteristic of the hydrograph provides a conclusion, that the recharge of unconfined ground water in quaternary aquifer takes place during the period of monsoon rain and quality of ground water due to tsunami has not changed specially.
R U K Piyadasa1, K D N Weerasinghe2, D S E Kumara2, H K C S Lakmal2
J A Liyanage3
1 Department of Geography, University of Colombo, Sri Lanka
2 Department of Agricultural Engineering, , University of Ruhuna, Sri Lanka
3 Dept of Chemistry, University of Kelaniya, Sri Lanka
Topics: symposium 2006 |