The Process and Mechanism of Water Erosion on Mudstone Regolith – a case study in Taiwan

• Main Authors: Ci-Jian Yang, 楊啟見
• Other Authors: 林俊全
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/72886550548109924792

碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 102 === In recent years, the whole world is facing the extreme rainstorm or drought due to global warming. For drought condition, the common micromorphology on dry soil is mud-cracks. It might cause serious problems on soil loss during high intensity rainstorms. It not only affects land use but also reduces slope stability. Therefore, for soil and water conservation, it is necessary to clarify the factors which may cause erosion, such as crack on soil erosion that we do not confirm yet. This research aims to simulate rill development by hydraulic flume and artificial rainfall simulator to understand the influence of micromorphology on erosion process. Mudstone specimens sampled from the mudstone area of Long-Chi, south western of Taiwan. We used ground LIDAR to record volume of erosion and change of landform during experiment. The ground LIDAR data provides high resolution elevation value. therefore high-quality DTM can demonstrate more detail on terrain changes. Results show that: (1) The erosion pattern of mudstone slope can be divided into four types: (a) sheet erosion(b) rill erosion (c) Failure (d) stable.(2) Slopes with mud cracks caused 125% more soil loss than non-mud cracks slopes. Moreover, mud cracks caused 120% more soil loss rate than non-mud cracks slopes.(3) Mud cracks will influence the spatial distribution of rill.(4) As far as sediment concentration is concerned, the initial concentration of sediment will increase by slaking. After that it increase by rill development and failure. (5) Whether the states of sample are dry or wet, the phenomenon of swelling will affect water erosion. (6)The evolution of landform on mudstone slope has restriction of erosion. The existing landscape of badland might through the several drying - wetting succession.