The 1997-1998 low rainfalls associated with the ENSO event affected some parts of Malaysia such as Federal Territory of Kuala Lumpur and Selangor State. In Selangor in February 1998 the water level in the Langat Dam was about 14m above critical level. By early April 1998 with the progression of the drought demanding release of water from the dam for abstraction downstream at KM 18 Ceras Treatment Plant and Tampoi Treatment Plant, the water level came close to critical level. According to the Water Supply Department, the estimated water demand for Selangor and Kuala Lumpur in 1998 was 2,658 mld. However, the water supplied in April 1998 amounted to 2,553 mld hence presenting a shortfall of 105 mld. Consequently, the tight water demand-supply situation caused by the dry weather condition during the on-set of the strong ENSO episode, non-revenue water and the sporadic water pollution at the intakes, prompted the Selangor State government to impose water rationing to 1.8 million residents in Klang / Langat River Basins from April to September 1998. This drought induced water crisis triggered the Government to find alternative water resources. In order to draw the policymakers’ and public’s attention to the potential benefits of rainwater utilization systems, it would be very beneficial to carry out this study for selected river basins. This study would enable the better understanding of the beneficial role of RWUS as supplementary sources of water to that of the existing public water supply and flood reduction, and also to establish the costs involved and the program implementation requirements of RWUS at a river basin and also on a regional scale.
To carry out a study for assessing the effectiveness and benefits of Rainwater Utilization Systems (RWUS) (for domestic, industry and miscellaneous use) on flood reduction and supplementing public water supply at the selected river basin, and also the associated costs/program to implement RWUS at regional scale over a period of five (5) years.