| Summary: | 碩士 === 國立中興大學 === 水土保持學系 === 92 === ABSTRACT
The 921 Chichi Earthquake resulted in lots of landslides in Wu River basin. Satellite image and digital terrain model were used to process the vegetation index analysis for identifying landslide sites and extracting topographic information in this study area.
A system coupled with GIS developed in this research has been effectively used to monitor and/or assess the recovery rate of vegetation for the landslides. Peak flow estimation and hydrograph simulation by the rainfall-runoff model were employed to analyze affecting parameters for flood events.
The correction coefficient (α,β) and the revised recession curve (R) calibrated from the observed data can be as the index of watershed characteristics. The correction coefficient α-value represents water conservation capability; the β-value can be employed as the index of sediment concentration in the runoff.
Vegetation analysis show that there exists a good trend of vegetation at the landslide sites of Chiufenershan (VRR= 22.9％ in 2000, 37.7％ in 2001, 58.5％ in 2002 respectively) and Ninety-nine peaks(VRR= 27.1％ in 2000, 40.3％ in 2001, 52.4％ in 2002 respectively) areas. Simulations shows that there is a negative correlation between α-value and the maximum rainfall intensity while a positive correlation between β-value and cumulative rainfall before peak flow. Better vegetation recovery rate results in less surface run-off in the watershed according to the model simulation in this study.
（keywords：Normalized difference vegetation index, Vegetation recovery, Landslides, Rainfall-runoff model）
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