Long Storage as Water Source during Dry Period for Sarawak River Basin

The recent drought in August 2009 which was triggered by the El Nino phenomenon had affected Kuching city to the extent that the city was facing critical shortage of water supply. In this study, the daily water demand for Kuching city was determined based on two major usages which were treated water demand for water supply production and for the flushing operation by the barrage in Sarawak River Basin for a selected year. These water demands were compared with the available supply from Sarawak River to determine the amount of water as storage to be prepared for critical shortage during the drier period. The results shows that the total maximum, average and minimum daily water demand for Sarawak River Basin are 8,715.264, 3,812.516 and 82.946 cumec.day respectively. The maximum daily demand was compared with the water supplied by Sarawak River Kiri at Kpg. Git station and from the flow mass curve; the needed storage is approximately 100 cumec.day for the critical period of May to October. A preliminary design for long storage has also been proposed to store water during the wet season to be used during the dry period.