Blessing turns into disaster

Mount Umyeon is known as the "lungs" of Seoul`s Gangnam district. Gangnam residents consider the green area 293 meters above sea level and surrounded by buildings and houses as a blessing of nature. Its shape resembling a dozing cow is the origin of the term "Umyeon." The mountain is covered with lush green plants. People often go hiking on trails on the mountain with a mineral spring and an ecological park. On the side of the mountain are high-rise apartments and suburban houses. The peaceful mountain changed its face overnight, however, as 15 people were killed and the area was wiped out. When mud swept the village away like a tsunami, the blessing of nature turned into disaster.

The landslide at Mount Umyeon is thought to be man-made. Two days of 460-milimeter rainfall were considered the direct cause of the disaster, but people were not fully prepared for it. A decade ago, the mountain was rated Ⅲ, an inappropriate grade for development, because the mountain slope turned out to be unstable in a landslide simulation test. Korea Forest Service gave Grade 1 -– the most dangerous level -- to the mountain in its landslide risk management system. The Seoul Metropolitan Government also categorized the area nearby the mountain Grade C (very dangerous). In September last year, Typhoon Kompasu hit the mountain, blowing hundreds of trees and washing away soil. The narrower buffer and weaker soil portended a large-scale landslide.

People built wooden steps to the mountaintop for the ecological park and changed waterways by making an artificial lake and valley on the risky mountain. The wider trails served as waterways, however, delivering rainwater and soil to the village. Gangnam Ring Road was designed to pass through the mountain based on weak soil. Residents said the piled-up trees plucked away by the typhoon at the site of a landslide increased the damage.

A road leading to the ecological park was destroyed in an ugly manner Thursday morning, the day after the landslide. Another road linked to a mountain path just 50 meters away remained unaffected, however. Nature gives the best blessing when left untouched. If touching nature is unavoidable, a geotechnical survey and safety measures must be conducted before doing so.

Another landslide like that of Mount Umyeon could occur in Korea because the volume and frequency of rainfall have dramatically increased due to climate change. Lee Su-gon, a professor at the University of Seoul who studied the potential risks of mountain landslides between 2006 and 2009, said, “Potential risk of landslide exist in 100,000 places in Seoul and one million nationwide, but there are no protective measures at all.” So mountain sides across the country should be thoroughly checked and measures to prevent landslides at mountains should be taken.