ผลกระทบของการเปลี่ยนแปลงสภาพภูมิอากาศโลกต่อการเกิดดินถล่มใน ต.เทพราช อ.สิชล จ.นครศรีธรรมราช

Abstract

Climate change effects have apparently increased natural disasters including the landslides in southem Thailand. This study aims to evaluate the effects of global climate change on landslides in Theppharat Area, Nakhon Si Thammarat Province which experienced landslides in 2011. This study consists of two main parts: the first part is the evaluation of periods and patterns of projected rainfalls that may cause landslides using statistically downscaled rain data generated from PRECIS/ECHAM4 model results. The second part consists of analysis of the rain that may cause the landslides in the area using groundwater seepage and slope stability models. Analytical results from these two main parts were used to evaluate the possible occurrence of landslides in the study area. Analytical results reveal that the landslide took place when the cumulative rainfall was over 600 mm within 3-4 days. According to filed observation, there was only one landslide in the past 29 years which corresponded to the retum period of 29 years. Rainfall projection results show that future rainfall will increase 6.3%, 12.6% and 16.8% from the base years in 2040, 2070 and 2090, respectively. Statistical downscaling results of rainfall projection by proportion and enhanced storm methods show no significant change of the landslide return period. On the other hand, landslide return period decreases from 29 to 6 years when the rainfall projection computed using add rain day method.