The frequency and severity of global drought-induced impacts have led to raising awareness of the need for improved river management. Although academic publications on drought have proliferated, a systematic review of literature has not yet been conducted to identify trends, themes, key topics, and authorships. This study aims to evaluate the scientific evidence for the hydrological drought characteristics and the methodologies by performing as a framework. This systematic review performed three-stage screening of literature review for current applicable hydrological drought studies that have been conducted since the year of 2000 concerning methodologies, literature research gaps, and trends, and contribute to future studies. The analysis shows the increasing trends of research and publications in the hydrological drought assessment. The primary research themes are hydrological drought is drought severity, drought vulnerability, and drought forecast. Despite the current research findings, spatial and temporal variability, low flow analysis and regional modelling are the most important to encourage a holistic approach and international collaborations. The finding identified the shortcomings of most research, which are the use of non-standardized methodological and distinct sample sizes, resulting in data summary challenges and unrealistic comparisons.

In recent decades, Malaysia has become one of the world’s most urbanized nations, causing severe flash flooding. Urbanization should meet the population’s needs by increasing the development of paved areas, which has significantly changed the catchment’s hydrological and hydraulic characteristics. Therefore, the frequency of flash flooding in Malaysia’s urban areas has grown year after year. Numerous techniques have been used, including the statistical approach, modeling, and storm design methods, in flood simulation. This research integrated hydrology and hydraulic models to simulate the urban flood events in the Aur River catchment. The primary objective is to determine water level and forecast peak flow based on hydrological assessment in the drainage system using XPSWMM software. The rainfall data for 60 min was used for this study in the hydrological analysis by obtaining an intensity-duration-frequency curve and peak flow value (Q peak). XPSWMM is used to simulate the response of a catchment to rainfall events in which runoff, water depth profile, and outflow hydrograph are obtained. Peak runoff is also obtained from the modified rational method for validation purposes. The proposed method was verified by comparing the result with the standard method. This is essential to identify flash flooding, which can lead to efficient flood mitigation planning and management in the urban catchment. The increase in residential areas results in the alteration of time of concentration, water quantity, and flow rate. Thus, to mitigate present and future problems, the effects of urbanization on water resources and flood should be analyzed.

Management of water supply in urban areas is a challenge that must be faced by water supply companies to ensure the continuity of domestic water supply to the residents in the area. Hence, this study aims to identify local people’s behavior and daily activities that led to domestic water wastage. Furthermore, the relationship between the demographic factors of the population trends in reducing water use through water savings in their daily activities or installing a home-saving water system is also undertaken. The data were analyzed and interpreted using IBM SPSS software such as descriptive analysis, covering frequencies, mean and standard deviation, correlation with bivariate correlation, cross-tabulation, and multivariate analysis (MANOVA). Availability and demand in water management will only be managed if water resources and water supply engineers address all the balance sides. It will ensure a more comprehensive and interconnected water sector, ensuring the security and sustainability of water.

This study was conducted using a modified drought risk assessment in which hydrological data were processed to assess the hazards and risk of hydrological drought in Peninsular Malaysia. Although drought vulnerability and risk assessment are critical components of the drought phenomenon, the lack of a comprehensive integrated drought risk assessment in Malaysia has led to increased socio-economic impacts. The Hydrological Drought Risk Index (HDRI) illustrates the relative importance of hazard and vulnerability assessments in drought risk management for Peninsular Malaysia using the Streamflow Drought Index (SDI). This study presents an integrated drought characteristics-based risk assessment framework to improve hydrological drought risk assessment. The hydrological drought risk assessment was conducted by combining physical hazard and socioeconomic variables across the region. The periods of 1998–1999 and 2017–2018 mark the most critical hydrological droughts. The results also show that the trend of hydrological drought in river basins is towards dry conditions with no change in the foreseeable future. This study proposes a theoretical framework for effective drought risk management that can be used by the government and its stakeholders for sustainable water resource management.

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 affected the pattern and processes of the hydrological cycle, resulting in the ability of the basin region to store water supply to decline. Reliability on water supply from river basins depends on their low-flow characteristics. The impacts of minimum storage on hydrological drought are yet to be incorporated and assessed. Thus, this study aims to understand the concept of low-flow drought characteristics and the predictive significance of river storage draft rates in managing sustainable water catchment. In this study, the long-term streamflow data of 40 years from seven stations in Selangor were used, and the streamflow trends were analyzed. Low-flow frequency analysis was derived using the Weibull plotting position and four specific frequency distributions. Maximum likelihood was used to parameterize, while Kolmogorov–Smirnov tests were used to evaluate their fit to the dataset. The mass curve was used to quantify the minimum storage draft rate required to maintain the 50 % mean annual flow for the 10-year recurrence interval of low flow. Next, low-flow river discharges were analyzed using the 7 d mean annual minimum, while the drought event was determined using the 90th percentile (Q₉₀) as the threshold level. The inter-event time and moving average was employed to remove the dependent and minor droughts in determining the drought characteristics. The result of the study shows that the lognormal (2P) distribution was found to be the best fit for low-flow frequency analysis to derive the low-flow return period. This analysis reveals September to December to be a critical period in river water storage to sustain the water availability during low flow in a 10-year occurrence interval. These findings indicated that hydrological droughts have generally become more critical in the availability of rivers to sustain water demand during low flows. These results can help in emphasizing the natural flow of water to provide water supply for continuous use during low flow.

Drought is considered a damaging natural disaster for economic, societal, and ecological impacts. The challenge of drought is to determine the drought characteristics, frequency, duration and severity, vital for drought's impact control and mitigation strategies. This paper adopts the spatial pattern of Streamflow Drought Index (SDI) for three, six, nine and twelve months for the tropical climate at Peninsular Malaysia. About 40 years of daily streamflow data based on 42 hydrological discharge stations were analyzed to obtain these indices. The area under drought stress during the study period at different time scales is stable and approximately 24 % of the total area. The years 1997–1999, 2002 and 2016–2018 mark the most critical drought years, with more than 48 % of the entire basin area under hydrological drought. According to the spatial evaluation of drought characteristics, short-term droughts are frequent in most regions, with relatively high severity and frequency in Northeast and Southeast of Peninsular Malaysia, where the maximum frequency reached 35.7 % and 42.8 %, respectively. This outcome emphasizes the importance and necessity of the basin's drought action strategies. Early detection of a probable hydrological drought can improve in the implementation of drought prevention or mitigation strategies.