The impacts of climatic and land surface characteristics on the storm-flood relationship in a tropical monsoon basin of Thailand

• Published in: Journal of hydrology (Amsterdam) 2023-01, Vol.616, p.128809, Article 128809
• Main Authors: Zhao, Baoxu, Wang, Taihua, Yang, Dawen, Yang, Shuyu, Lu, Weiwei, Santisirisomboon, Jerasorn
• Format: Article
• Language: English
• Subjects: afforestation; basins; Chao Phraya River Basin; climate; climate change; deforestation; Elasticity analysis; flood control; hydrology; monsoon season; Storm-flood relationship; Thailand; typhoons; watersheds
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2022.128809

•The variations of the annual-maximum storm and flood peaks are depicted in the UCPRB (Upper Chao Phraya River basin).•The storm-flood elasticity of the storm and flood peaks is estimated.•Climatic covariates show larger impacts on storm-flood elasticity than land surface covariates in most sub-basins. Storms and the resultant floods have always been catastrophic disasters and raised increasing global concerns in the context of climate change. However, the relationships between storms and floods remain largely elusive. Here we examine the storm-flood relationship and its variations in the Upper Chao Phraya River Basin (UCPRB), a typical tropical monsoon basin in southeast Asia. The distributions of storms and floods are characterized by statistical models with the aid of climatic and land surface covariates. The storm-flood relationship is depicted by the concept of storm-flood elasticity, which represents the corresponding changes in flood peaks in response to changes in the storm peaks with the same return period. The storm-flood elasticity coefficients for 100-year return period events range from 0.61 to 1.20, and the values of storm-flood elasticity coefficients tend to be smaller for long-return period events than for short-return-period events, under high-typhoon-precipitation (high-TP), high-non-typhoon-precipitation (high-nTP), and low-forest (low-F) conditions, and in humid regions than in arid regions. The climatic covariates are shown to have stronger effects on the storm-flood elasticity coefficient than the land surface covariate in most basins. In the basins where deforestation shows strong impacts on the storm-flood relationship, afforestation can be an effective approach for flood control. In most basins in the UCPRB, the variation of typhoon precipitation has larger impacts than those of non-typhoon precipitation, indicating that typhoon precipitation should be paid more attention to when considering the future changes in floods. The findings help develop a better understanding of storm-flood relationships in tropical monsoon regions, and the methods of this study can also be applied in other climate regions.