Application of Physically-Based Erosion Model to Analysis of Soil Loss in Shankung Watershed.
Date Issued
2012
Date
2012
Author(s)
Chang, Yu-Teng
Abstract
Soil erosion is an important issue for watershed management. However, the lacks of reliable soil erosion estimation limited strategies and activities relating to the disaster mitigation and sedimentation management. Also, previous studies have estimated soil erosion rate by using empirical models, but those ignore the mechanics behaviors and rely large amount of calibrated data. In this study, the GeoWEPP model was applied to estimate soil erosion in the Shankung watershed and the soil parameters was determined by soil sampling and experiment. Then, the model’s applicability and limitation were compared with USLE model and validated by method. And the effects of DEMs with different resolutions on predicting watershed erosion were investigated.
The results show that the average soil erosion rate estimated by GeoWEPP- Flowpath and Watershed method are 79.2 t/ha/yr and 89.1t/ha/yr , respectively. The erosion rates are 2.4 and 2.7 times more than the rate (33.21t/ha/yr ) estimated from. Therefore, flow length > 100 m was assumed to be ephemeral stream and the soil erosion rate where flow length > 100 m was been excluded. Then, soil erosion rate by Flowpath Method was 28.55 t/ha/yr, which is similar with the rate estimated from and had better performance than the estimation by USLE (13.7 t/ha/yr ), especially where flow-length < 30m. Furthermore, 5 meter DEM has better a detailed of influence of erosion on topographic characteristics. And after modification, 20m DEM get the similar estimation with value due to widely modification area. This study suggested that GeoWEPP with flow-path modification has acceptable performance applying in mountain forest watersheds in Taiwan.
Subjects
Soil erosion
Physically-Based Erosion Model
137CS
Type
thesis
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