Qualifying sediment dynamic in a reservoir watershed is essential for water resource management. This study proposed an integratedmodel ofGrid-based Sediment Production and Transport Model (GSPTM) at watershed scale to evaluate the dynamic of sediment production and transport in the Shihmen Reservoir watershed in Taiwan. The GSPTMintegrates several models, revealing landslide susceptibility and processes of rainfall-runoff, sediment production from landslide and soil erosion, debris flow andmassmovement, and sediment transport. Formodeling rainfall-runoff process, the tanks model gives surface runoff volume and soil water index as a hydrological parameter for a logistic regression-based landslide susceptibility model. Then, applying landslide model with a scaling relation of volume and area predicts landslide occurrence. The Universal Soil Loss Equation is then used for calculating soil erosion volume. Finally, incorporating runoff-routing algorithmand the Hunt'smodel achieves the dynamical modeling of sediment transport. The landslide module was calibrated using a well-documented inventory during 10 heavy rainfall or typhoon events since 2004. A simulation of Typhoon Morakot event was performed to evaluate model's performance. The results show the simulation agrees with the tendency of runoff and sediment discharge evolution with an acceptable overestimation of peak runoff, and predicts more precise sediment discharge than rating methods do. In addition, with clear distribution of sediment mass trapped in the mountainous area, the GSPTMalso showed a sediment delivery ratio of 30% to quantify how much mass produced by landslide and soil erosion is still trapped in mountainous area. The GSPTMis verified to be useful and capable of modeling the dynamic of sediment production and transport atwatershed level, and can provide useful information for sustainable development of Shihmen Reservoir watershed.
All Science Journal Classification (ASJC) codes
- Geography, Planning and Development
- Aquatic Science
- Water Science and Technology