Settlement Isolation Susceptibility due to Heavy Rain Caused Road Closure
On August 9, 2009, Typhoon Morakot struck Taiwan, triggering landslides and debris flows and destroying transportation infrastructure in the southern mountains. Many settlements in this area were isolated due to road closure. Residents were trapped in the settlements and unable to evacuate to safe places. Also, emergency goods were unable to be transported to the settlements. In order to minimize the loss of life and property associated with future typhoon, public administrators should evacuate residents before access routes to settlements are affected.In this study, settlements in Lao-Nong River basin of Southern Taiwan were ranked in accordance to isolation susceptibility. Susceptibility was estimated by overlaying maps of landslides, debris flows, temporary roads and primary mountain road layers. Criteria used to evaluate the isolation susceptibility were developed using an expert-based approach. The isolation susceptibilities of settlements were categorized into 3 levels, namely high, moderate and low.