Good quality water is essential for all living beings. Even modern technologies could
not change our dependency on water. We are more concern about this natural resource
when it becomes too little, too much or too dirty. Until recently, the quantity of water was
not an issue in the country, except in the dry regions of the Peninsula. Sabah and Sarawak
did not face any serious shortage of raw water yet. Majority of the potable water is tapped
from the rivers, which are fed by the rain. On average the Peninsular Malaysia receives
324 billion m3 of rainwater annually, where as the current demand is about 11 billion m3
only [1]. The demand in the year 2050 could be about 18 billion m3. As such, it is
understood that the availability of raw water in the country, generally, is not an issue. The
problem is due to the fact that rainfall is not uniformly distributed over the year temporally
and spatially; baseflow is reduced due to urbanisation, supply is less than the demand in
the city centres, distribution network is not adequate to transfer water from the low
demand to the high demand areas, water get polluted and rendered less suitable for the
intakes when passing through the urban centres.
Variation of annual rainfall is not that significant in Malaysia except during the El-
Nino spells. The annual rainfall at one of the well maintained gauging station at DID
Ampang branch is shown in Fig. 1. Despite ignoring the rainfall during the missing days,
the recorded data showed a slightly increasing trend of annual rainfall. Thus, water
scarcity is not a common phenomenon in Malaysia. The recent shortages are due to nonuniformity
of rainfall and improper distribution and management of the water resources.
However, availability of good quality raw water is reducing. This is reflected in the
number of polluted and slightly polluted rivers are increasing, as shown in Fig. 2.
Shortage of water is mainly faced in the city centres where the water demand is high.
Besides quantity, quality of water resources also concerns the relevant authorities. Quality
of the surface water is degraded by point and non-point sources pollutants. Legislations
are available in the form of Environmental Quality Act (EQA) 1974, which deals mainly
with point source pollutants from the domestic and industrial sources [2]. Other
regulatory Acts are available at State and Federal levels to protect the rivers.
Besides the point sources (sewage, sullage, industrial effluent, etc.), pollutants from
the non-point sources (urban and rural runoff) are also responsible to make river water
unsuitable for our uses. Management of the pollutants from the point and non-point
sources are equally important for sustainable management of water resources. This
statement is apparently true as it is observed that despite the implementation of the EQA
for more than two decades (which mainly controls point sources) the trend of river water
quality is not improving until 2000. It is the year 2001 when significant improvement in
the river water quality status was observed which might be linked to the endorsement of
the urban stormwater management manual for Malaysia (Manual Saliran Mesra Alam,
MSMA) by the cabinet in 2000 [3].