The Study of Slope Green Cover and Water Conservation – An Example at Zhu-keng River Sub-Catchment

• Main Authors: Liu Shufang, 劉淑芳
• Other Authors: Cheng Kuiyhong
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/495zc3

碩士 === 高苑科技大學 === 土木工程研究所 === 101 === Due to comprehensive characteristics for fragile geographical and environmental factors in Taiwan, sediment is highly susceptible to erosion and loss due to the frequently changes of short-term but strong rainfall along with steep terrain, especially during high temperature summer weather. It is also vulnerable to be attacked by typhoons in recent years in Taiwan, such as the disaster caused by Typhoon Morakot in the southern Taiwan in 2009, resulting in landslides region washed into the river, whose fine-grained sediment material to downstream migration as secondary disasters. Based on the above reasons, this study refers to the fourth inventory and planning report “river catchment assessment, slopeland treatment and disaster prevention” from Soil and Water Conservation Bureau, Council of Agriculture, Executive Yuan. We took Jhu-Keng River sub-catchment in Pingtung County as a case study to research weakening area in sub-catchment and further propose construction method through verification with together on-site exploration and green cover image evaluation. Comparing both 2005 and 2007 green cover through image analysis method, the results show that the green cover was 93.1% in 2005 and 96.0% in 2007, indicating 2.9% increases. Moreover, projected annual sediment of 6,279 tons and its erosion depth of 0.01 cm in sub-catchment caused by soil erosion formula erosion calculation, thus, the amount of sediment output of 749 tons compared with the sub-watershed area (3,317 ha) is quite amazing, showing the situation of insufficient green cover. It is recommended that the slopeland could be built as piling knitting gate methods, and mostly cages revetment remediation in both sides of streams against pushing damaged by debris in critical areas.