Abstract
The present paper investigates the vulnerability of urban areas in the Mekong Delta to inundation due to seasonal flooding, a phenomenon which is likely to be exacerbated by future sea-level rise. The research reveals that ocean tides predominantly determine water elevation even in an upstream location such as Can Tho City, 80 km inland from the river mouth, and that the river flow causes tidal damping and effectively reduces the energy of the incoming tides. This tidal damping is especially pronounced during the rainy season. Analysis based on the water levels monitored by the Mekong River Commission revealed that the ground near the riverbank of Can Tho City had experienced inundation for a total of 215 hours between July 2009 and June 2010 (2.5 % of the time over a one year period). Assuming three scenarios of SLR of 20, 40, and 60 cm, all within the range of the IPCC AR4's projections, it was found that the duration of inundation will be prolonged from the present percentage of 2.5 % to 6, 13.2, and 23.9% of the year, respectively. It is thus feared that in the future inundation can occur during any season of the year, whereas it is mostly limited to the rainy season under present sea levels. Furthermore, the field survey carried out by the authors shows that inundation reached up to a height of 47 cm above the roads of Can Tho downtown on November 2009. Such flooding can influence daily life, agriculture and traffic in the region and an increase in their frequency and height due to sea-level rise can have negative consequences on the socio-economic conditions of the inhabitants of the delta.
