Characteristics of Groundwater from Fractured Hardrocks in West Coast of Peninsular Malaysia
The thesis examines on the chemical characteristics of groundwater found in granitic and metasedimentary rocks of the West Coast of Peninsular Malaysia. A total of 133 tubewells having diameter 20 cm were studied. The wells were drilled to a depth between 100 to 200 m. The top 20 to 40 m of the...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1997
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8637/1/FSAS_1997_22_A.pdf |
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| Summary: | The thesis examines on the chemical characteristics of groundwater
found in granitic and metasedimentary rocks of the West Coast of Peninsular
Malaysia. A total of 133 tubewells having diameter 20 cm were studied. The
wells were drilled to a depth between 100 to 200 m. The top 20 to 40 m of
the wells were cased, fol lowed by 60 to 80 m Of slotted casing. The
remaining depth of the wells was left open. The present study shows that the
quality is mostly fresh with average pH and conductivity around 6.5 and 200
µS/cm respectively. The total dissolved solids range between less than 100
mg/l to more than 200 mg/l with average of a bout 120 mg/l. The
groundwater is classified as soft to hard water because the hardness ranges
between 12 mg/l to 180 mg/l. the groundwater facies was found to be
Calcium Bicarbonate, Magnesium Bicarbonate and Sodium B icarbonate water. Calcium and Magnesium in metasedimentary water have average of
about 17 mg/l and 21 mg/l, respectively. For granite, the average of Ca and
Mg is 8.75 mg/l and 2.85 mg/l. The amount of iron content can be as high as
15 mg/l with average of 1.5 mg/l. More than 50% of the groundwater
samples exceeds the limit of iron for drinking water of 0.3 mg/l. Fluoride
concentration is generally low with average Of 1.0 mg/l. However,
groundwater from granite can reach the level of Fluoride to 11.5 mg/l. the
groundwater is classified as medium to low salinity hazard and low in
sodium; therefore it is suitable for irrigation.
The thesis also examined the production capability of the hardrock
aquifers. The top 20 m was mainly in the residual soil and weathered part of
the rock. Fresh hardrocks were normally encountered at depth more than 40
m. the static water level or water table in the study area were found to be less
than 20 m deep. Four of the wells were outflowing automatically above the
well head casings, which was constructed about 0.5 m above ground. High
discharge rates up to 800 m³/well/day were encountered from wells that
penetrated major fracture zones. Average discharge rate for metasedimentary
and granite aquifers were 400 m³/well/day and 300 m³/well/day, respectively
and the drawdown is generally less than 50 m from the ground level. The
wells were drilled for various purposes such as for rubber, latex, textiles and
mineral water bottling factories, poultry and agricultural activities and
domestic water supply. |
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