A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management

Thesis (M. Eng.) - Asian Institute of Technology, 2023

Sea level rise (SLR) is a momentous impact of climate change, and it poses a significant threat to coastal communities worldwide. As sea levels continue to rise, coastal areas are becoming more vulnerable to extreme sea levels, including storm surges, coastal floods, and erosion. Assessing the impact of coastal flooding due to sea level rise is of critical importance for policymakers, urban planners, and coastal managers to develop effective strategies for future risk management. This study aims to project future coastal flooding in Rayong Province, Thailand, using two different approaches, the bathtub method and MIKE21 hydrodynamic modeling and to assess the impact on selected critical infrastructures in monetary terms using flood depth to damage functions. It was found that the future absolute sea level in Rayong will reach 0.5 m under RCP 8.5 by 2100. The study found that the bathtub method provides larger estimates of inundation area when compared to MIKE21 FM HD modeling results. A total damage of € 1,581,303 is expected under SLR of 0.26 m and € 2,168,933 under SLR of 0.51 m. The future permanent inundation due to sea level rise will pose the greatest impact on commercial buildings such as shrimp farms, harbour, institutional lands, recreational areas, hotels and resorts. The maximum possible damage due to extreme sea levels (ESL) was estimated to be €67,854,985 under ESL of 2.37 m. The impact assessment revealed that the selected critical infrastructure in Rayong Province is at significant risk of damage due to coastal flooding. Shrimp farmlands were found to be affected by coastal flooding in most scenarios. The results of the study provide valuable insights for policymakers and planners to develop effective strategies for mitigating the impact of coastal flooding on critical infrastructure. The study highlights the importance of using accurate modeling approaches and impact assessment methods to make informed decisions about coastal flood risk management.