| Author | Gajasinghe, Sajeewan Kavishwa |
| Call Number | AIT Thesis no.WM-26-06 |
| Subject(s) | Climatic changes--Environmental aspects--Thailand
Sea level--Thailand
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| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Extreme Sea Level (ESL), arising from the main contributions of storm surge, tides, and wave setup, constitutes a critical hazard for coastal regions under climate change. This study quantifies the effectiveness of mangroves as a nature-based solution for attenuating ESL and associated hydrodynamic impacts within a site-specific context at Ban Pret Nai, Trat Province, —2 nd richest mangrove forest in Thailand. Concurrently, the implications of climate change on mangrove stability and functionality are evaluated.A coupled hydrodynamic–spectral wave modeling framework was implemented to obtain total water levels and flow currents under present and future climate conditions. Future projections were based SSP2-4.5 and SSP5-8.5 pathways for mid-century (2040–2060) and late-century (2080–2100) periods, incorporating atmospheric forcing from Copernicus ERA5 reanalysis and CMIP6 EC-Earth3 outputs. Simplified vegetation model was developed by NDVI analysis and geometry parameterization based on tree age. Peak Over Threshold approach with Generalized Pareto Distribution was employed to estimate return levels of ESL and Extreme weather-induced currents (EIC) for 1-, 10-, and 100-year return periods. Hydro-ecological impacts were assessed by evaluating inundation durations relative to hypoxia thresholds.Mangroves attenuate ESL by 61.63 ± 2.62% and EIC by 61.17 ± 12.30% across all climate conditions. The attenuation exhibits limited sensitivity to climate forcing, indicating a quasi invariant protective capacity of mangrove under climate change. While EIC attenuation declines moderately with climate severity, reinforcing its utility as an innovative proxy indicator for erosion potential. Mangrove effectiveness increases rapidly during early stages and stabilizes with maturity. A dimensionless relationship between ESL and tree height reveals that when ESL exceeds canopy level, attenuation is constrained with a maximum effectiveness of ~ 15.7% for ~3.25-year-old homogeneous vegetation.Prolonged inundation durations exceeding hypoxia thresholds may persist for up to ~10 days under future climates, compared to ~3 days under present conditions, suggesting elevated physiological stress and potential degradation risks of mangrove with climate change. Furthermore, comparison with global-scale ESL projections reveals that localized modeling estimates ESL ~ 40% lower, underscoring the necessity of site-specific assessments. |
| Year | 2026 |
| Type | Thesis |
| School | Faculty of Civil and Environmental Engineering (2026) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Engineering and Management (WEM) |
| Chairperson(s) | Natthachet Tangdamrongsub;Sutat Weesakul (Co-chairperson) |
| Examination Committee(s) | Babel, Mukand S.;Hassan, Nurul Husna Binti |
| Scholarship Donor(s) | Thai Pipe Scholarship;AIT Scholarship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2026 |
