Flood vulnerability assessment in the light of rice cultivation characteristics in Mekong River flood plain in Cambodia

More than 2 million hectares of the lower Mekong River flood plain (Cambodian Plain), which extends from southern Cambodia to the border with Vietnam, is cultivated with rice; and more than 60 % of the population in the flood plain are farmers involved in rice cultivation. Rice production in this area is seriously affected by floods almost every year; on the other hand, the farmers need floodwater for their crop fields. Therefore, the farming in this area is about coping with floods, and flood countermeasures should be carefully planned based on good understanding of the livelihood of the farmers. Thus, this study aimed to identify flood-vulnerable rice-growing communities in the Mekong River flood plain in Cambodia. In this research, we proposed a useful methodology to make flood inundation maps by conducting a simple analysis by combining satellite-based digital elevation model (DEM) and river water level data based on the flood characteristics in this area. Then, rice-crop vulnerability maps were derived from previous maps and results from other past researches using the geographical information system (GIS). Comparison among those maps was also conducted to find out the relationship between DEM and people’s lifestyles in this area. This simple, inexpensive methodology was proven useful to understand major crop damage and vulnerability in relation to floods in this area, based on flood characteristics in the Cambodian flood plain. Because the method is a GIS-based approach, it can deliver more accurate results when provided with more accurate data.

     

Flood vulnerability assessment in the light of rice cultivation characteristics in Mekong River flood plain in Cambodia

Demographic changes, such as aging and depopulation in rural areas, are major reasons for the recent abandonment of the terraced paddy fields in Japan. In addition, the low productivity of terraced paddy fields, due to their small area and the difficulty of using machinery on the plots, further abet this trend. Recent research has shown a growing interest in multifunctional conservation and maintenance of the ecosystem and traditional agro-culture of terraced paddy fields. This paper aims to elaborate on the conservation activities of endangered terraced paddy fields in Japan, by using the case of Shiroyone Senmaida to discuss conservation experience and lessons, and recommend future strategies for adaptive management of the rice terraces under the GIAHS framework, as well as the next necessary steps for research. As an outstanding cultural landscape and tourist attraction in Noto Peninsula, the conservation scheme combining financial support from governmental subsidy, the “owner system” of interaction with urban dwellers, and labor support by conservationist volunteers has contributed to the conservation of traditional farming on Senmaida’s terraced paddy fields. Still, as is the case in other parts of Japan, lack of financial support and an aging farming population threaten conservation of terraced paddy fields in Noto Peninsula.