塊石堆砌工設置方式對淺水域魚類棲地品質改善評估

本文以淺水域河流型態的台北市內湖內溝溪為研究案例，同時採用水槽試驗及水平二維水理模式TABS─2，量化分析設置塊石堆砌工前後之流況變異，及對魚類利用棲息地的改善效果。水理條件設定成福祿數0.42及0.61兩種、塊石堆砌設置方式分成單組及雙組兩類、魚類則針對鯉科（游泳性魚類）及平鰭鰍科（攀爬性魚類）兩種不同移動模式的魚種。本區原始流況較適合平鰭鰍科魚類，設置塊石工後，則以鯉科魚類的峻地品質改善效益較顯著。在福祿數為0.42的情況下，設置塊石工法均導致棲地多樣性上升、魚類可用棲地面積下降；在福祿數為0.61的情況下，設置塊石工後棲地多樣性均上升、鯉科可用棲地面積增加、平鰭鰍科可用棲地面積則下降；此結果顯示塊石堆砌工的設置對棲地多樣性的提升有較顯著而一致的效果。在工法間距的安排上，無論是單組或雙組塊石配置，間距加大均有助於魚類可用棲地面積地增加、棲地多樣性上升，最佳工法間距為2-2.5倍河寬，故建議現場施作的間距可控制在2.5倍河寬左右。本文研究結果可補強現場施做塊石堆砌工的理論強度，並釐清塊石堆砌工的生態效宣言，對現地生態工法的設計及應用應能提供實質的幫助。

關鍵字

塊石堆砌工；魚類棲地；棲地多樣性；水工模型；數值模式

並列摘要

A flume experiment and a horizontal 2D model, TABS-2, were examined to evaluate the hydraulic characteristics of Nei-Go Stream in Northern Taiwan. The simulated water depth and velocity magnitude were employed to calculate both percentage usable area (PUA) for fish and Shannon-Weaver diversity index (SHDI) for habitat type. In addition, by selecting Cyprinidae and Homalopteridae fishes as the indicator species, habitat improvement performance with and without riprap works were investigated. Due to occupation of ripraps in riverine, the fish habitat area decreases under low Froude number (Fr=0.42) situations. Meanwhile when Fr is equal to 0.61 installing riprap works can decline Cyprinidae's habitat area but rise Homalopteridae's ones. All cases reveal that habitat diversity is getting higher after constructing riprap works. Besides, we found out that the optimum distance between two ripraps set is about 2-2.5 times of river width.

並列關鍵字

Riprap works ； Fish habitat ； Habitat diversity ； Flume experiment ； Numerical model

國際替代計量

塊石堆砌工設置方式對淺水域魚類棲地品質改善評估

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