An aquifer characteristic analysis for identifying ground water resource development alternatives in the wet zone of Sri Lanka

Abstract

A proper management system for groundwater resources in the wet zone of Sri Lanka is crucially needed to avoid further exploitation of the resource leading to deterioration of groundwater quality. This research study mainly targets on the assessment of groundwater in the wet zone of Sri Lanka by means of collecting and analysing available groundwater pumping and aquifer characteristic data towards the identification of best management practices. The pumping test data are collected from well locations in Kalutara district and transmissivity values are estimated using both Theis and Cooper Jacob methods. The estimated transmissivity values are used to identify the spatial variation of transmissivity. It is recognized that there is no particular pattern identifiable in the spatial distribution of estimated transmissivity values, however, with the limited data set available. The observation is in line with the fact that there exists significant groundwater anisotropy and heterogeneity even within the same locality or within a single distinct aquifer system. The transmissivity values are further analysed using statistical testing and Krasny's classification system, transforming the data set into log distribution and assigning an index value to identify best management practices for selecting suitable locations for both local water supply schemes and landfills. The places with positive anomalies are very suitable for locating local water supply schemes, and the places with negative anomalies are best to have toxic waste disposal sites or landfills.