The relationship of rainfall energy with landslides and sediment delivery

In tropical mountainous areas, typhoon-induced rainstorms trigger extensive landslides and deliver huge amounts of sediment to river basins. Two mountainous catchments in central Taiwan, with 0.8-13.5% of their catchment areas disturbed by landsliding induced by a series of typhoons, were selected for the purpose of quantifying the impact of typhoon-induced rainfall kinetic energy on landslides and sediment transport during 1994-2008. Distribution analysis of the rainfall kinetic energy required to trigger landslides revealed the threshold at which rainfall kinetic energy Ek induces landslides in the mountainous catchments of central Taiwan to be approximately 2000Jm ^-2. The present study demonstrates that higher rainfall kinetic energy causes more sediment to be delivered to rivers, and finds a positive relationship between Ek and sediment transfer during typhoon periods. We postulate that real-time monitoring of rainstorms can be used to predict the impact of typhoon events by applying the threshold of rainfall kinetic energy needed to trigger landslides and transport of huge amounts of sediment.