Vietnam has high potential for flash floods

Flash floods are natural disasters that occur in most countries, especially in midland, mountainous and river deltas affected by monsoons, hurricanes, low pressure and tropical convergence. 

Vietnam has high potential for flash floods, as more than 70 percent of its territory is hilly.

Many methods of early flood warnings have been studied, including the use of remote sensing data in combination with GIS.

Scientists from the Military Engineering Academy and Hanoi University of Natural Resources and Environment have used remote sensing data and GIS technology to draw a map of forecasting flash flood risks in Huong Hoa district of Quang Tri province.

A survey in 2009-2010 in Quang Tri province found 177 landslide sites in the province, of which 81 are in Huong Hoa district.

The landslide stricken area in Huong Hoa accounts for 52.2 percent of total landslide area of Quang Tri’s hilly and mountainous areas. Complex weather, plus storms with increasingly high intensity, all give favorable conditions for the formation of flash floods.

The prediction and mapping of flash flood-risk areas is an important task which helps mitigate damages caused by flash floods. 

Huong Hoa district is 400 meters above sea level with large slopes, divided by rivers and streams.

Nguyen Thi Thu Nga, a member of the Military Academy of Technology, said that to build up the map, the research team focused on eight factors that affect the formation of flash floods, including cover density, soil moisture, slope, transport, current land use situation, rainfall, soil and water density.

Analyses found that there are high or very high risks in 15 percent of total area of Huong Hoa district. 

Remote sensing technology and GIS, with outstanding advantages over conventional research methods, can be used effectively in the development of flash flood warning maps. 

The use of GIS and remote sensing methods with statistical data can bring results with high accuracy

The map of landslide risk along Highway 6 in Hoa Binh province has also been developed with the modern technology.

Nguyen Phi Son, Deputy Director of the Institute for Geodesy and Cartography, said that remote sensing technology and GIS also play an important role in developing a soil erosion map. Soil erosion is a major cause of land degradation.

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