Thailand plays a central economic and policy-making role in Southeast Asia. Although climate change adaptation is being mainstreamed in Thailand, a well-organized overview of the impacts of climate change and potential adaptation measures has been unavailable to date. Here we present a comprehensive review of climate-change impact studies that focused on the Thai water sector, based on a literature review of six sub-sectors: riverine hydrology, sediment erosion, coastal erosion, forest hydrology, agricultural hydrology, and urban hydrology. Our review examined the long-term availability of observational data, historical changes, projected changes in key variables, and the availability of economic assessments and their implications for adaptation actions. Although some basic hydrometeorological variables have been well monitored, specific historical changes due to climate change have seldom been detected. Furthermore, although numerous future projections have been proposed, the likely changes due to climate change remain unclear due to a general lack of systematic multi-model and multi-scenario assessments and limited spatiotemporal coverage of the study area. Several gaps in the research were identified, and ten research recommendations are presented. While the information contained herein contributes to state-of-the-art knowledge on the impact of climate change on the water sector in Thailand, it will also benefit other countries on the Indochina Peninsula with a similar climate.

No abstract

No abstract

<p>Rainfall affects urban traffic flow. In rapidly urbanizing megacities in Asian countries, heavy rainfall causes roads to flood and traffic congestion to worsen due to weak drainage systems. This study statistically quantified the impact of rainfall on urban traffic speed in Bangkok, using probe vehicle data and rainfall data from 2018 to 2020. Traffic speeds are calculated based on the travel distance and travel time between districts, taking into account the detouring of flooded sections.</p><p>Results show that both the rainfall intensity at the time of driving as well as the amount of previous rainfall affect the traffic speed reduction. In particular, the impact of previous rainfall increases at times and areas where traffic is concentrated, such as during the weekday morning and evening peak hours and travel to/from the city center. The results of the analysis based on regional characteristics show that low-lying districts are more affected by the previous rainfall because the flood water tends to stay on the road surface, while districts with high vegetation index (NDVI) are less affected by the previous rainfall. In addition, the impact of previous rainfall increases with population density and the ratio of narrow streets. In Bangkok, urbanization has progressed while leaving behind a city block configuration with many narrow streets, called Soi, connecting to arterial roads. This result means that limited road space is prone to flooding, and once flooding occurs, combined with the concentration of traffic on adjacent roads, traffic congestion becomes more severe.</p><p>The results of this study showed the impact of rainfall on urban traffic in different areas and at different times of the day in the target site. Integrated improvements to the transport and drainage systems could have a greater benefit.</p>

No abstract