Analyze Fluvial Feature for the Preservation of Primary Freshwater Fish under Extreme Precipitation

• Main Authors: Hsien-ChangHsu, 許獻彰
• Other Authors: Jian-Ping Suen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/99363518032609785219

碩士 === 國立成功大學 === 水利及海洋工程學系專班 === 98 === Located in subtropical monsoon climate zone, Taiwan not only is hit by 3.5 typhoons in average every year but also has short streams and small river basins, which can threaten the stability of species and community of Taiwan’s terrestrial freshwater fish. Moreover, because of climate change in recent years, violent storms happen more often. Especially, torrential rain come with a typhoon usually brings great floods and vastly destroys river environment. Extreme precipitation and the possible impacts are gradually valued. In aspects of conservation of Primary Freshwater Fish, how habitat preserves the species will be discussed in this dissertation. Firstly, using geologic factors, including stream power index, flood capacity, ratio of meander, and diversity of stream slope, adequacy of using habitat as species preservation will be analyzed. Secondly, in the flood disaster, if every reach can become fish’s shelter and how to increase survival groups of a community will be discussed as well. Thirdly, methods of how to divide reach preservation hot spots are developed and used to divide the hot spots in the samplings. In this study, GIS is used to divide fish species habitat preservation hot spots into impact and non-impact areas. The result indicates that both water conservancy index and flood capacity index are more obvious to the identification of river’s fish preservation ability, but ratio of meander and diversity of stream slope aren’t. Beside the basic index which is adequate for suitability area, the developed model in this study can be used to draw hot spot map of fish distribution and identify more advantageous reach for conservation. At the same time, this analysis of habitat factor impact can be the referral aspects for the design of government artificial structures. Toward the work of stream fish conservation, the relative impact assessment of conservation area designation and artificial structures is expected.