Sediments originated from landslides occupies the major proportion of sediment budget of catchments in highly active orogenic belts of Taiwan. Sediment budget defines and quantifies the processes of production, transportation, and residual. The processes among these categories are highly interacted with each other. To understand the characteristics of sediment yields and the sediment budgets in Taiwan, this study integrated a conceptual modelling approach to quantify the amounts of sediment production, transport, and residual of watersheds in pre-and post-Typhoon Morakot periods (during 2008~2012 periods). We calculated the landslide-induced sediments production by using multi-temporal landslide inventory and volume-area relations derived from 2,535 landslide samples. The amount of sediment transport was simulated from a rainfall-runoff model (HEC-HMS) and rating curve relations between river and sediment discharges that developed based on field survey from WRA. Based on the principle of mass conservation, the sediment residual was calculated by the amount of sediment production minus the transport of a catchment. The results show that the Typhoon Morakot in 2009 triggered massive landslide-sediment and which is significantly over the capacity of sediment transport. Among all the watersheds during 2008~2012 periods, the Kao-ping River has highest sediment production with 643 × 106 m3, and the second and third highest values are in the South-Taitung and Chou-Sui River with 367 × 106 m3 and 137 × 106 m3, respectively. The top two watersheds of highest sediment transport is the same with that of highest sediment production. The Kao-Ping River and Chuo-sui River transported 354×106 m3 and 350×106 m3 of sediment, respectively. In residual sediment, the Kao-Ping River catchment remains the highest sediment with 289 × 106 m3; and the South-Taitung Catchments is the second highest with 188 × 106 m3. The processes and results of sediment budgets analyzed in this study are expected to benefit the policies for watershed general management and to control landslide-induced sediments under the circumstance of extremely highly rainfall (e.g. Typhoon Morakot in 2009, which rainfall was more than 3,000 mm in 3 days).
|Number of pages||20|
|Journal||Journal of Taiwan Agricultural Engineering|
|Publication status||Published - 2016 Sep|
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)