摘要 本研究為探討河川水理條件與生物棲地之關係，彙整國內外有關流量與棲地量化評估技術，以烏溪上游為研究區段，在低水流況下考慮河川地形特性，於多槽河段利用HEC-RAS 3.0模式進行分流演算。並以台灣特有種台灣石魚賓 作為指標魚種，使用RHABSIM 2.2模式進行棲地分析，探討分流情況下流量變化對於該地魚類棲地面積等之影響。結果顯示分流演算時，在分流河段較能反應斷面地形特性。本研究樣區分流段經分流演算所得之魚類棲地面積與未考慮分流前之棲地面積相較下，更能表現出實際河川魚類棲地概況。最後以溪內水流增量法(IFIM)探討流量變化與魚類棲地面積之關係，建議研究樣區內之生態基流量。 ABSTRACT In this study the relationship between hydraulic conditions and ecological habitats is discussed and compared with habitat quantization assessment technology. Taking upstream of Wu-Chi River for example, geography of the reach in low flow is considered and the cross section of the stream is divided into several independent channels. HEC-RAS 3.0 is used to compute divided flow situation. Selecting Acrossocheilus paradoxus as the index fish species, the habitat is analyzed by RHABSIM 2.2. According to divided flow computation, we can show how flow change influences the fish habitats. The result shows that divided flow computation can take into account the characteristics of geography in the multiple channels reach. The estimation of fish habitat using divided flow computation can present actual habitat status. Finally an ecological instream flow requirement in the research reach is suggested.
