Recent increases in sediment disasters in response to climate change and land use, and the role of watershed management strategies in Korea

Suk Woo Kin, Jin Ho Lee and Kun Woo Chun

Recent climate change caused by global warming has affected the environment in Korea , resulting in increased precipitation and frequency and magnitudes of typhoons. From 1994–2003, a mean of 2.3 days/year experienced heavy rainfall (≥80 mm), in contrast to a mean of 1.6 days/year from 1954–1963. Of the ten typhoons that have resulted in the maximum daily rainfall over the last ten decades, seven occurred between 1990 and 2007. The maximum instantaneous wind velocity of typhoons has greatly increased from 20 m/sec (in the 1970s) to 40 m/sec (in the 2000s). Furthermore, increases in the occurrence and scale of forest fires and landslides, as well as increased infrastructure and land use, contribute to sediment disasters. Accordingly, environmental changes and human-induced factors have resulted in significant increases in the magnitude and frequency of natural disasters, especially in the Gangwon region on the east coast of Korea . Therefore, in 2004 the Korea Forest Service instituted an integrated and environmentally-friendly system for forest management, which has helped prevent sediment disasters. Multiple prevention strategies are also required in addition to these systemic changes to forest structure management, including control of hill-slope erosion and torrent erosion, debris flow mitigation, water storage and slit dams, grade-stabilization structures and forest improvement, and watershed management.