A Multimethod Approach towards Assessing Urban Flood Patterns and Its Associated Vulnerabilities in Singapore

Abstract

We investigated flooding patterns in the urbanised city-state of Singapore through a multimethod approach combining station precipitation data with archival newspaper and governmental records; changes in flash floods frequencies or reported impacts of floods towards Singapore society were documented. We subsequently discussed potential flooding impacts in the context of urban vulnerability, based on future urbanisation and forecasted precipitation projections for Singapore. We find that, despite effective flood management, (i) significant increases in reported flash flood frequency occurred in contemporary (post-2000) relative to preceding (1984–1999) periods, (ii) these flash floods coincide with more localised, “patchy” storm events, (iii) storms in recent years are also more intense and frequent, and (iv) floods result in low human casualties but have high economic costs via insurance damage claims. We assess that Singapore presently has low vulnerability to floods vis-à-vis other regional cities largely due to holistic flood management via consistent and successful infrastructural development, widespread flood monitoring, and effective advisory platforms. We conclude, however, that future vulnerabilities may increase from stresses arising from physical exposure to climate change and from demographic sensitivity via rapid population growth. Anticipating these changes is potentially useful in maintaining the high resilience of Singapore towards this hydrometeorological hazard.

Urban Vegetation Types are Not Perceived Equally in Providing Ecosystem Services and Disservices

“…The pollutant standards index (PSI) reached a historical high of 401 in Singapore on 21 June 2013, with haze events of various intensity occurring in Singapore almost every year [50]. While severe flooding is rare in Singapore, flash floods have become more common in recent years [53]. The magnitude of these floods is small in comparison to those afflicting some other cities, but they receive significant coverage in the local media and have led to changes in water management [53,54].…”

Trans-boundary variations of urban drought vulnerability and its impact on water resource management in Singapore and Johor, Malaysia

“…We adopt a commonly-used systems framework defining urban vulnerability to drought as the combination of attributes of (a) exposure to drought, (b) demographic sensitivity to this hazard, and (c) the urban socio-economic capacity to adapt towards drought impacts (figure 2) [28,29]. In this study, spatio-temporal changes in urban vulnerability is examined via corresponding variations in each attribute, and can be documented for both Singapore and Johor using a combination of available climate and archival data.…”

“…Further, the region's low-latitude and low-elevation reduces a potential imprecision of PDSI arising from a key assumption that all precipitation is immediately available for supply as Figure 2. Conceptual framework of urban vulnerability to droughts based on previous frameworks in [28,29]. Ovals are component factors of overall vulnerability with example physical and social attributes relevant for drought italicised.…”

Climate change and growing megacities: hazards and vulnerability

“…The peak intensity of rainfall is likely to occur not only in geographical areas where the surface air flow converges, which can happen in mountains, but also within megacities, which affect regional climates (Benson-Lira et al, 2016;Chow et al, 2016;Holst et al, 2016;Georgescu et al, 2012;Shepherd et al, 2011;Smith et al, 2013). The prediction of rainfall and flooding in the low-lying and almost completely urbanised areas of the island of Singapore is improving as a result of detailed computational models and a dense network of real-time data (Chow et al, 2016;Pereira et al, 2014). Deeper convection caused by climate change effects on the troposphere makes such events more likely in future.…”