_Table 1: Impacts of large floods_

|**Year**|**Duration(days)**|**No. people affected(m)**|**Damages($m 2022 price)**|
|---|---|---|---|
|1996|35|1.30|2.8|
|2000|31|3.45|272.0|
|2001|97|1.67|24.8|
|2002|101|1.47|0.2|
|2011|84|1.64|677.8|
|2013|21|1.50|628.1|

Notes: Table shows floods with more than 1m people affected in Cambodia since 1990. Source: EM-DAT database.

In the period since 1990, four floods have impacted more than 50,000 km<sup>2</sup> in Cambodia, representing more than a quarter of the country’s total land mass. Davies and others (2014) report that 18 of the 24 provinces were impacted in the 2011 floods. The 2011 floods affected more than 10 percent of the population and caused over $677 million in damages (5.3 percent of GDP). Even if the floods do not hit major urban centers (meaning that monetary damages are much reduced), the impacts on agriculture and transport infrastructure can be substantial. Despite the 2011 floods having the highest recorded cost in terms of damages, ADB (2012) suggests that more than half of the damages could be attributed to agriculture (particularly rice paddy) and transport infrastructure. Furthermore, damage to transport infrastructure can have important implications for providing disaster relief and assistance in recovery (Davies and others, 2014), which increases the possibility of cascading disaster effects (see next section).

The impacts of disasters can be difficult to identify in macroeconomic statistics because efforts to rebuild can create a stimulus effect that counterbalances production losses during the disaster. However, ADB (2012, p.2) reported a noticeable long-term impact on economic development in Cambodia from the 2011 floods: “Despite the positive overall economic performance of Cambodia in 2011, the flood slowed the potential for sustained economic growth due to the devastating impact at the household and macroeconomic levels.” Even in cases where resources are diverted toward recovery efforts, there could be displacement effects, for example if public services are cut to balance budgets. Alternatively, an increase in debt levels could impact financial stability, as discussed in Section 4.

Table 1 shows that large floods with substantial human and economic cost already occur in Cambodia on a frequent basis, in part because of the intensity of rainfall in the rainy season (when 80 percent of annual rainfall occurs). Paltan and others (2018) report that climate change will increase the frequency further; even under a scenario with limited climate change, what was previously a 1-in-100-year flood could occur once every 25 years or even once every five years. World Bank Group (2021) summarizes the recent literature and finds that 25 percent of Cambodia’s population is expected to be exposed to floods between 2035 and 2044.

However, there remains substantial uncertainty about both the scale and potential impacts of future floods. Phy and others (2022) note that Cambodia lacks both flood hazard mapping and risk and damage assessment. The authors recommend further data collection and model-based analysis, combined with predictions about future land use change and infrastructure development, to identify key future risks in Cambodia.