碩士 / 國立臺灣大學 / 森林學研究所 / 92 / 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.
| Identifer | oai:union.ndltd.org:TW/092NTU05360053 |
| Date | January 2004 |
| Creators | Jyh-Dar Huang, 黃郅達 |
| Contributors | 陳明杰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 104 |
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