Overtopping risk of high-hazard embankment dam under climate change condition

extreme flooding amidst climate change and emphasizing proactive measures to fortify criti- cal infrastructure and protect downstream communities. Introduction Dams have been built worldwide to offer a range of benefits, including generating hydropower, controlling floods, supplying water to residential areas, and supporting agricultural activities, with the overall goal of fostering the progress of nations. There are 60,000 dams worldwide, with China and the USA, the world’s largest economies, leading by constructing the most dams [1]. As the demand for water and economic growth has increased, there has been a sig- nificant increase in the construction of large dams [2]. Embankment dams are the most built dams, with 64% being earth fill, 13% being rockfill, 23% concrete and other forms and the remaining 32% being concrete and other forms of dams. The remaining 32% are composed of concrete and other forms of dams [3]. As the oldest and most prevalent large dam type [4], embankment dams hold significant importance globally due to their cost-effectiveness and availability of material [5]. However, they also face the highest frequency of failures among dams [1]. Apart from the numerous benefits provided by dams, they also represent critical infrastruc- ture, and in the event of failure, downstream areas can suffer catastrophic consequences [6]. The failure of embankment dam is mainly driven by hydrological overload [7]. Generally, an embankment dam is constructed using compacted earth, rocks, or other suitable material and

not designed to handle overtopping, as that can cause rapid erosion of embankment dam material. The pressure put by climate change on dams is beyond the dam’s original design. In the past, many dams were developed assuming stationary climate conditions [8]. Today, resil- ient, and sustainable water planning and management must consider global climate change, which determines the region’s socioeconomic growth [9] Climate change has caused a rise in air temperatures, resulting in a 7% increase in the atmo- sphere’s ability to hold water for every 1˚C increase. This has led to more frequent and intense rainfall events [9]. The past three decades saw the warmest years in history, with global temper- atures rising between 0.65 and 1.06˚C from 1880 to 2012 [10]. There have been alterations in rainfall patterns, resulting in a higher occurrence of intense rainfall in certain areas [11, 12], whereas other regions have experienced a decrease in rainfall [13, 14]. Studying the trend of rainfall at the regional level is highly crucial for precisely modelling how rainwater responds in a given area. Several studies have explored how climate change affects Malaysia’s hydrological pattern, focusing on exceptionally heavy rainfall. [15] examined rainfall-related extremes throughout Malaysia’s east coast from 1971 to 2010, while [16] examined precipitation events from 1975 to 2004. In 2015, another study studied Malaysian seasonal extreme precipitation from 1975 to 2010. [17] found more Northeast monsoon wet days and rainfall depth. [18] showed inter-

monsoon 1-hour storm intensity above 20 mm increasing. [19] found an increase in daily and yearly rainfall depths along Peninsular Malaysia’s east coast. [15] studied the impact of El Niño and La Niña on rainfall extremes in Malaysia. These studies provide evidence of Malaysia’s shifting hydrological patterns, specifically the increased frequency, severity, and length of extreme rainfall events, underlining the impact of climate change. However, research into future hydroclimate in Malaysia is limited in the literature. [20] measured Peninsular Malaysia’s water resources from 2025 to 2050. Then in 2013, with the PLOS ONE Climate change PLOS ONE | https://doi.org/10.1371/journal.pone.0311181 February 27, 2025 2 / 32 Competing interests: The authors have declared that no competing interests exist.