Evaluation and validation of flood hazard zoning using Analytical Hierarchy Process and GIS: A case study of Lam River basin (Vietnam)

Abstract

In recent years, the Lam river basin had suffered various forms of natural disasters such as floods, inundations, windstorms, tornadoes, etc. Among all these, the flood has proved to be the greatest threat to the people and the socio-economic development in the basin. Moreover, it is very frequent as compared to other natural disasters. In view of the fact that such disastrous floods are still occurring in the basin, it becomes a necessity to determine the causes and analyze the components affecting flood. This is important in order to develop an early flood warning system and thus minimize the negative impact of flood in the Lam river basin on the people and the facilities. In this paper, the Analytical Hierarchy Process (AHP) analysis method integrated with GIS technology is used to map flood risk zones in the Lam river basin. The parameters used for the analysis are the main causes affecting the floods. In addition to the 5 most commonly used factors such as slope, rainfall, land cover, soil, and drainage density, this study also includes a new factor - relative slope length to compute a more rigorous and reliable model. The results were compared with the two more methods of flood hazard zoning in the same study area: the method of the main flood caused factor analysis and the method of inheriting, data analyzing, and processing. The results were also validated by the historical flood data of three years 2010, 2013, and 2016.

Soil Properties Variation Valued in Relation to Land Use and Management Practices in Vietnam

“…The study area is within the Lam River Basin (LRB), which is located in northeastern Nghe An province, Vietnam (1750-2050N and 10314-10610E) and it covers an area of 17730 km 2 (Fig 1). The geography is gradually tilted from northern to southern and eastern to western; the altitudes from 120 a.m.s.l to 1200 m a.m.s.l and strongly separated with three typical zones the plains, midlands and highlands (Nguyen et al, 2021;Hung et al, 2017). There areas of forestry, agricultural lands and other types of land are irregularly distributed on the whole study basin (Dinh and Sima, 2022;Dung et al, 2021).…”

“…There areas of forestry, agricultural lands and other types of land are irregularly distributed on the whole study basin (Dinh and Sima, 2022;Dung et al, 2021). The area has a tropical monsoon climate which comprises a dry season and a rainy season all year round, creating the background of a mean annual temperature approximately of 24.5C, rainfall of about 2100 mm and a relative humidity of 85% (Nguyen et al, 2021).…”