[A-CG45] AsiaPEX field campaign strategies for changing Asian monsoon precipitation

[ACG45-05] "Socio-Hydrological Dynamics of Flooding and Agricultural Resilience in the Lower Brahmaputra River Basin"

*Marina Langhu¹、Taikan Oki¹、Masashi Kiguchi¹、Shinichiro Nakamura² (1.Department of Civil engineering, The Graduate School of Engineering, The University of Tokyo、2.Department of Civil and Environmental Engineering, Nagoya University)

キーワード：socio-hydrology, flood risk model, agricultural production, flood risk management

This study investigates the socio-economic and environmental determinants influencing human settlements in high-risk floodplains of the Lower Brahmaputra River Basin, emphasizing their interactions with monsoon-driven hydrological extremes. Using a socio-hydrological modeling framework, it integrates multi-dimensional quantitative data including population dynamics, agricultural production, hydrological variables and social memory with qualitative assessments to quantify flood-induced impacts on agricultural systems and associated risk dynamics. Agricultural production was modeled independently from demographic factors to isolate the effects of flood events on food security, agrarian livelihoods and economic resilience facilitating a more granular understanding of system vulnerabilities. The findings indicate a continued expansion of settlements in flood-prone areas, largely driven by agricultural dependence and large scarcity despite recurring flood hazards. Additionally, the study identifies a strong socio-hydrological feedback loop, where communities with frequent flood exposure develop increased flood memory and adaptation strategies, yet continue to face economic vulnerabilities. While certain adaptive measures such as staggered cropping, elevated storage facilities and crop diversification have help mitigate agricultural losses, overall resilience remains a challenge. To address this challenge, future research will focus on developing a coupled demographic-agricultural model to enhance predictive capabilities and better capture human-water interactions. This integrated approach underscores the necessity of linking demographic and agricultural subsystems to accurately assess socio-hydrological feedback and inform sustainable development strategies for flood-prone regions.