富源溪集水區魚骨型魚道水理特性之研究

Study of Hydraulic Characteristics for Fish-Bone-Type Fishway in The Fuh-Yuan Creek Watershed

黃郅達(Jyh-Dar Huang)

指導教授 ： 陳明杰

國立臺灣大學/生物資源暨農學院/森林學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.02502

摘要

魚骨型魚道又稱改良型舟通式魚道，屬丹尼爾式魚道之變型，依相關文獻顯示，此種魚道可提供多種魚類使用並兼具良好排砂效果，為目前較適應台灣河川特性，且適用於針對防砂壩做棲地改善之可行魚道種類之一。
魚骨型魚道係以魚道內橫斷面不斷突擴及突束作用，加以底床魚骨型材質之擾流及阻流效果，達到降低魚道內流速之目的。因魚道內屬非等速均勻流且流場相當混亂，以往針對此類魚道研究多偏向於魚類可溯性及排砂功效等，缺乏相關水理特性研究。
本研究係在既有防砂壩上設置實體鋼筋混凝土魚骨型魚道（底寬180cm，深度100cm，阻水區高度50cm，阻流材高度20cm），並設定以台灣鏟頜魚為指標性魚種。除了以該案例來探究該型魚道應用在防砂壩上可能遭遇的問題外，更詳細記錄該型魚道在暴雨過後，魚道內流速分佈情形，與指標性魚種之限制流速條件加以比對，並實際放游指標魚種加以驗證，獲得多項有意義且實用之結果。
研究結果發現，在坡度1/10、流量0.22cms及0.144cms情況下，魚道內流場屬超臨界流流況且表面呈現連續水躍現象，因受橫斷面不斷突擴及突束消能作用，以及底部魚骨型阻流材阻流影響，其各橫剖面之流速分佈差異頗大，約在0.02∼2.5m/sec之間。流速剖面最快發生在魚骨中心光滑處上方，其次為魚骨型阻流材上方，再者為阻流材與突束段阻水區交接之最窄斷面處（魚類溯游主要通過區域）；突擴段休息區及阻流材間則呈現渦流狀態，流速大幅降低，可供魚類溯游時暫棲。
在放游試驗中發現，以身長平均20cm台灣鏟頜魚為對象，放游24小時後上溯率為100%。其中完全通過占40%，另外60%暫棲於魚道內休息區或魚骨阻流材間。

關鍵字

防砂壩 ； 魚道 ； 流速分佈 ； 台灣鏟頜魚

並列摘要

The fish-bone-type fishway belongs to the variation of the Daniel type fishway, is also called the refining Larinier type fishway. In relative documentation, it was found that the fish-bone-type fishway is suitable for multiple fishes and has good effect for sediment elimination. Therefore, the fish-bone-type fishway is one of the feasible fishway for adapting the characteristics of the rivers in Taiwan and approving the habitats around the check dams.
In fish-bone-type fishway, continuous sudden expansion and sudden contraction cross sections, and the disturbance effect of flow due to bed material were used to decrease the flow velocity in the fishway. Because of the flow field in the fishway is very complex, most of the previous researches in fishway were focus on the tracing-back ability of fishes and the effect of sediment elimination, but relative hydraulic characteristics researches were lacked.
In this research, a RC fish-bone-type fishway (180 cm in width of the bottom, 100 cm in depth, 50cm in height of the water-disturbance area, and 20cm in height of the water-disturbance material) was set up on an existed check dam, and the Varicorhinus barbatulus was taken as the index fish. This case not only showed the possible problems in the application of using this type of fishway for check dams, but recorded thoroughly flow velocity distribution in the fishway after a storm. Compared with the limited velocity of the index fish and verified by putting the index fish into the fishway, several meaningful and practical results were gained.
It was found that in the condition of 1/10 in gradient and 0.22cms and 0.144cms in flow rate, the flow in the fishway was super-critical and continuous water-jumps were on the surface. The energy still dissipated because of the sudden expansion and sudden contraction cross sections and the fish-bone structure. Thus, the difference of velocity among cross sections was quite huge, about 0.02~2.5m/sec. The fastest velocity happened in the up of fishway center, the velocity in the up of fish-bone material and the narrowest water-passed cross section were the second. In the sudden expansion area and between the materials, fish can take a break for a while because the flow condition were vortex and the velocity decreased rapidly.
It was found in the experiment of putting index fish (average body length in 20cm Varicorhinus barbatulus) into the fishway that the tracing-back rate after 24 hours was 100%. 40% of the index fish were through the fishway completely, the other 60% were in it.

並列關鍵字

fishway ； check dam ； Varicorhinus barbatulus ； flow velocity distribution

參考文獻

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