DOMESTIC USES AND REDUCING PEAK URBAN

Rapid socio-economic development has begun to put a strain on Malaysia’s water supply and drainage facilities. This strain came to the fore on the back of the 1998 drought induced water shortages which brought unpleasant water supply disruptions for 1.8 million residents in the Klang and Langat Valley. This drought event jolted the nation to explore alternative water resources such as rainwater for conserving the public water supply. Similarly rapid urbanisation which brought an increase of impervious areas and reduction of natural storages has increased urban peak runoff, burdening city drainage systems and compounding city flash flood problems. Consequently, NAHRIM embarked on a study on rainwater harvesting and utilisation system (for non-potable household use), coupled with detention storage (to reduce peak storm runoff), for a double storey terrace house at Taman Wangsa Melawati, Kuala Lumpur. The rainwater system comprises of gutters, downpipes, first flush storage, rainwater cum detention storage tank, a pump, a roof tank and separate distribution pipes. The rainfall and runoff from the roof are measured and the non-potable water use of the house occupants is also metered. Sizing of the storage tank is done taking into consideration reliability of the delivered water, roof catchment area and space constraints in the house compound. The economic aspect of the system such as unit cost of rainwater is also determined. The rainwater quality in the storage tanks are compared with the pipe