A Study of the sustainability of a water supply scheme utilizing a costal aquifer with particular reference to the Koggala export processing zone

Abstract

Koggala Export Processing Zone of the BOI was setup in 1991 and functions with 20 Nosfactories and work force of over 10,000 in the Galle district just adjacent to the sea andcoastal belt. Total extent of the KgEPZ area is 225 Acres. Since there were no surface waterscheme to provide the required water for this project, a groundwater scheme was consideredas an appropriate alternative resource. NWS&DB has plan to supply water from the TalpeReservoir of Gin Ganga Project (KfW) with part of the cost shared by the BOI.The purpose of this study is to study the sustainability of the existing water supply schemein Koggala EPZ where a coastal aquifer is used as the source. Since about 50% of the landare vacant and could be given for future investment projects in the KgEPZ, the possibilityof continuation of operation of existing groundwater scheme supplemented with surfacewater supply is considered as an economical solution for the KgEPZ.For estimation of recharge water balance calculations were done for time step of 1 day,since in a time step of 1 day would capture all the relevant changes that occur.This study estimated that recharge to the aquifer is 0.4 Million cubic metres per year whichis equivalent to 357 mm/year.n