| Summary: | 碩士 === 國立臺灣海洋大學 === 河海工程學系 === 95 === Soil erosion usually results in agricultural losses and environmental disasters. Since soil erosion phenomenon is quite complicate, it has difficulties to develop universal simulating models for soil erosion. Although many empirical methods have been developed for sediment yield estimating, the applications of these methods are still limited in some specified watershed geomorphologic and hydrologic conditions. The objective of this study is to develop a fully-distributed soil erosion numerical simulating model (SENS) based on soil erosion mechanism. Two modified Universal Soil Loss Equations (MUSLE I & MUSLE II) were also developed for comparison to realize the possible differences for sediment-yield estimating during rainstorms using different approaches.
Hydrologic and sediment yield records from Goodwin Creek experimental watershed in Mississippi of America were adopted to investigate the adequateness of the proposed models for sediment yield simulating during storms. The results indicate that the SENS can perform a good simulating for sediment yield because the mechanisms for soil particles transport and deposition from overland to downstream channel were included in the model structure. Since the soil erosion simulation in MUSLE I is controlled by rainstorm intensity, the simulated result of MUSLE I is comparatively poor and the estimating of the sediment-yield peak is found always overestimated. Although the simulated sediment-yield hydrographs by using the MUSLE II close to the recorded hydrographs, significant differences for the total sediment-yield volume between the simulated and the recorded hydrographs are found.
Keywords: soil erosion, soil erosion numerical simulation model, sediment yield, universal soil erosion equation.
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