Hard rock formations consisting of granite and metasedimentary rocks in Peninsular Malaysia, have beenconsidered to be of poor aquifers. The map of shows the area underlain by hard rock as having poorto moderate potential for groundwater production (
Groundwater in fractured metasedimentary rock in Malaysia is a potential source of water for drinking and industrial uses. Industries including agricultural processing, mineral water bottling, manufacturing and golf courses pumped the water from the underlying fractured rocks. Fifty eight tubewells belong to private companies operating in various places in West Coast of Peninsular Malaysia were evaluated for their yield and quality of water. Rotary percussion methods were used for the drilling to a maximum depth of 200 m. The productivity of the wells and the characteristics of the aquifer were evaluated by pumping test using both the constant discharge rate and steps drawdown methods. The average yield of the wells at allowable drawdown of 40 m was found to be 416 m3 per day. Results from water quality analysis indicated that the water was fresh with an average total dissolved solids (TDS) concentration of 101 to 150 mg/L. The hardness of the water varies from as low as 13 mg/L to a maximum of 353 mg/L. On the average, the water was moderately hard with the average hardness value of 80 mg/L. The water facies of the groundwater was found to be of calcium-sodium-bicarbonate water.