Assessing extreme flood inundation and demographic exposure in climate change using large ensemble climate simulation data in the Lower Chao Phraya River Basin of Thailand

• Published in: Journal of hydrology. Regional studies Vol. 50; p. 101583
• Main Authors: Budhathoki, Aakanchya, Tanaka, Tomohiro, Tachikawa, Yasuto
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2023; Elsevier
• Subjects: at-risk population; climate; Climate change; climate models; d4PDF; data collection; Flood inundation; IMCR; Lower Chao Phraya River Basin; Population exposure; runoff; Thailand; watersheds; Thailand; Population exposure; d4PDF; Lower Chao Phraya River Basin; Climate change; IMCR; Flood inundation
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2023.101583

Lower Chao Phraya River Basin (LCPRB), Thailand. This study aims to make a robust assessment based on a large ensemble d4PDF dataset and a flood-inundation model Inundation Model Coupling Rainfall-runoff (IMCR) for the LCPRB. Inundation area and depth for 100-year flooding are evaluated for the flood volume of capacity greater than 2000 m3/s for both past (1951–2010) and future (2051–2100) climates. This study also evaluates the affected population exposure in the region for both past and future climate scenarios. The IMCR inundation simulation findings indicate that compared to the historical climate, the inundation area increases by an average of 1.0–1.4 times, and the critical area (depth >3 m) increases by an average of 1.1–1.3 times. On the other hand, the exposed population in the future, with respect to the SSP5 scenario "Taking the Highway," is expected to decrease on average by 0.7–0.9 times in comparison to the past climate for depth > 0 m. However, keeping the population constant as in the past, the exposed population is likely to increase on average by 1.3–1.4 times in comparison to the past climate for depth > 0 m. [Display omitted] •Probabilistic impact of + 4 K climate on flood inundation was analyzed with d4PDF.•100-year flood inundation area will increase by 1.0–1.4 times.•Urban area inside King’s Dyke will be protected even in + 4 K climate.•Population exposure for 100-year flood will change by 0.6–1.0 times.•That under 3.0 m depth will change by 0.7–0.8 times.