The FAO-ESCAP pilot project on national water visions. From vision ...

<strong>The</strong> maximum and minimum mean air temperatures are 33.4°C and 22.8°C respectively. <strong>The</strong> highest
and lowest recorded annual rainfall are 5 130 mm (Sarawak, 1994) and 1 350 mm (Perlis, 1992)
respectively. As for the number of rainfall days, the maximum recorded is 260 (Sarawak, 1995). <strong>The</strong>
mean annual relative air humidity varies between 78 and 87 percent; this high humidity is due to the
high temperature and high rate of evaporation. All parts of the country receive an average of 1 764 to
2 664 bright sunshine hours a year. <strong>The</strong>se data are based on the last ten-year records (1989-1999).
<strong>The</strong> water resources in Malaysia are summarized in Table 1. Groundwater accounts for 90 percent of
the freshwater resources. <strong>The</strong> renewable water resources are 630 billion m 3 – the summation of
surface runoff and groundwater recharge. This translates into an annual average water availability of
about 28 400 m 3 per capita. Based on this fact, Malaysia is a country with abundant water resources.
Table 1. Water resources in Malaysia
Annual rainfall 990 billion m 3 (Ref 1)
Surface runoff 566 billion m 3
Evapo-transpiration 360 billion m 3
Groundwater recharge 64 billion m 3
Surface artificial storage (dams) 25 billion m 3 (Ref 2)
Groundwater storage (aquifers) 5 000 billion m 3 (Ref 3)
Streams and rivers with and without impounding reservoirs contribute 98 percent of total water used
in Malaysia; the remainder is contributed by groundwater. River flow regimes are irregular and to
secure safe yield from surface water sources, storage facilities were constructed. Currently, there are
47 single-purpose and 16 multipurpose dams (Table 2) with a total storage capacity of 25 billion m 3 .
<strong>The</strong> main reason for the lack of groundwater use in the country is the easy availability of surface
water resources; there are over 150 river systems in Malaysia (Ref 3).
Table 2. Dams in Malaysia
Single-purpose dams
Water supply
Hydropower
Irrigation
Silt retention
Subtotal
Multipurpose dams
Water supply + Irrigation
Water supply + Flood mitigation
Water supply + Irrigation + Flood mitigation
Hydropower + Flood mitigation
Hydropower + Water supply
Subtotal
Source: (Ref 2)
34
7
3
3
47
6
5
2
2
1
16
<strong>The</strong> water demand for 1980 and 1990 and the <strong>project</strong>ed demand for 2000 are given in Table 3; the
values within the brackets refer to the proportions of the total water use. Table 4 shows the national
water supply production capacity and coverage and non-revenue water (NRW) for 1990 and the
<strong>project</strong>ed figures for 2000. Due to the rapid population increase and the rapid growth of industries, the
annual water demand for the domestic and industrial sector has been expanding at the rate of about 12
30
National water visions in Southeast Asia