Determination of drainage corridor in the downstream Vu Gia - Han river, Da Nang city

Abstract

Flood is one of the most well-known phenomena in the Central Vietnam where Da Nang city is located. As the most area in the central coastal part, this city frequently suffers to flood without any prevented structure like sea dike or river levee. The only thing that can help to the response for flood is emergency plans. Therefore, flooding still causes great damages to the economic development and social stability in this region. For ensuring the sustainable development of Da Nang city under the impacts of climate change and sea level rising, it requests a change in direction of the solution, from the flood control to the adaptation and living with floods through spatial planning to make a good condition for optimal drainage corridors. This paper suggests a design flood drainage corridors for Da Nang city that was developed by combining of mathematical model, GIS, hydro-meteorological documents of Vu Gia - Thu Bon basin from 2009 to present. These proposal solutions include (i) widening of the riverbed and providing a river corridor protection along both river banks; (ii) creating of drainage channels for the land between the rivers and (iii) creating of space for floodwater in an appropriate time. The result was so good and it helps to reduce the flood in Da Nang from 5% to 10%. Therefore this would be a scientific basis for identifying the flood drainage corridors of other river basins in the central coastal region without typical dike cover.