Hydrological drought and the sustainability of water resources in Malaysia: An analysis of the properties of the Langat Basin, Selangor

Accelerated urbanizatioan that comes with rapid development has resulted in a dramatic increase in the number of urban centers and inducing demand for clean water exponentially. To assess the sustainability of available water resources for human use, indicators such as Annual Cumulated Duration (ACD) and Annual Maximum Deficit Volume (AMDV) may be adopted to demonstrate the extreme drought namely the. In addition percentile Q90 and Q95 scores obtained from the flow duration curve may also be employed to express drought extremes whereby Q90 denotes moderate drought and Q95 severe drought. This study analysed extreme discharge indicators in the Langat River Basin. Results showed that droughts hit in around 14 years at the Q90 levels which covered 29.2% of the entire record. These included 1970, 1976-1978, 1980, 1982, 1985, 1987, 1989, 1996-1999, 2002 and 2006. As for Q95, the number of droughts were 4 years (1977, 1980, 2002 and 2006) and covering 8.3% of the entire record period. The average recurring drought hit around every three years at Q90 and every 12 years at Q95. The droughts had disturbed water supply a situation aggravated by the high population density, rapid urbanization and the complexity of the hydrological cycle. All this resulted in episodes of even short drought. The responsible parties should thus pay due attention to the water resources management so that crises in clean water supply caused by droughts could be prevented.