摘要：Rapid urbanization in the state of Selangor, Malaysia,has led to a change in the land use, physical properties of basins,vegetation cover and impermeable surface water. These changes have affectedthe pattern and processes of the hydrological cycle, resulting in the abilityof the basin region to store water supply to decline. Reliability on watersupply from river basins depends on their low-flow characteristics. Theimpacts of minimum storage on hydrological drought are yet to beincorporated and assessed. Thus, this study aims to understand the conceptof low-flow drought characteristics and the predictive significance ofriver storage draft rates in managing sustainable water catchment. In thisstudy, the long-term streamflow data of 40 years from seven stations inSelangor were used, and the streamflow trends were analyzed. Low-flowfrequency analysis was derived using the Weibull plotting position and fourspecific frequency distributions. Maximum likelihood was used toparameterize, while Kolmogorov–Smirnov tests were used to evaluate their fitto the dataset. The mass curve was used to quantify the minimum storagedraft rate required to maintain the 50 % mean annual flow for the 10-yearrecurrence interval of low flow. Next, low-flow river discharges wereanalyzed using the 7 d mean annual minimum, while the drought event was determinedusing the 90th percentile (Q90) as the threshold level. The inter-eventtime and moving average was employed to remove the dependent and minordroughts in determining the drought characteristics. The result of thestudy shows that the lognormal (2P) distribution was found to be the bestfit for low-flow frequency analysis to derive the low-flow return period. Thisanalysis reveals September to December to be a critical period in riverwater storage to sustain the water availability during low flow in a 10-yearoccurrence interval. These findings indicated that hydrological droughts havegenerally become more critical in the availability of rivers to sustainwater demand during low flows. These results can help in emphasizing thenatural flow of water to provide water supply for continuous use during lowflow.
