Effect of Metro rail extension on flood risks of Bangkok Metropolitan Authority outskirt due to climate and land use land cover changes

Abstract

ABSTRACT The Bangkok Metropolitan Administration's expansion, driven by economic growth, includes extending Metro systems and altering land use. This transformation, especially noticeable near these routes, has led to shifts in land cover – reduced green spaces, increased impervious surfaces, and decreased water storage. These changes, coupled with denser population and higher waste-generation, have compromised drainage efficiency, amplifying flood vulnerability. This study focuses on Pink Line's 34.5-kilometre stretch from Khae Rai intersection along Tiwanon Road to Min Buri, aiming to evaluate Flood Vulnerability Index (FVI) near the Metro line, identify critical influencing factors and propose mitigation strategies. The analysis divided the study area into five zones based on characteristics, evaluating FVI using population density (PO), drainage efficiency (DE), impervious ratio (IR), garbage management (GB), and pond area ratio (PA). FVI values ranged from 0.41 to 0.55. Sensitivity analysis showed minor FVI impacts at Lat Pla Khao and Ram Intra km.4 stations due to DE and IR, with reduced FVI at Khu Bon and Eastern Ring Road stations from PA and GB improvements. PA and IR enhancements consistently lowered FVI, while fluctuations were observed with GB and DE changes, with notable impacts at Min Buri Market Station. Understanding factor sensitivity aids in planning local mitigation-strategies.