圖書典藏及影音數位平台

石岡壩魚道，於921地震復建時，於右岸壩體受損之16號溢洪道所增設，90年12月11日完工。設計水流量0.3立方公尺，其入口(出水口)標高259.57公尺、出口(進水口)標高269.40公尺、總長147公尺，屬於水池階段式(Pool and Step or Pool and Weir Type)，係供洄游生物使用。 歷年(截至2021年)石岡壩魚道及其上下游之測站中，記錄14科47種魚類，甲殼類3科9種。生態調查結果顯示此河段的環境污染低且生物資源相當豐富。而歷年監測可說明石岡壩魚道的效果良好，本區的水域生態還是維持在相當好的程度，且上下游之間都有非常豐富的河川生物資源。 因此，本計畫工作項目包括：(ㄧ)長庚橋至埤豐橋（含魚道）水域生態及洄游生物監測調查、(二)建立石岡壩魚道及其上下游水域生物物種名錄、(三)探討石岡壩魚道及其上下游之水理及水質與水域生物分布關係、(四) 辦理環境教育推廣活動、(五)綜整歷年生態資料與統計分析、(六)評估石岡壩下游在建工程中對於陸域、水域生態及生態關注區域的生態環境及其變動及有關生態保育措施、(七)工作報告及成果報告編撰印製等。

The ecological monitoring of fishway and the upper and lower reaches of Shih-Gang Dam was complied on March 7-10, June 6-9, August 22-25, and November 6-9, and two additional investigations of Shih-Gang Dam fishway were complied on April 26 and September 25. The fishway discharge normally during the investigations, and the water are sufficient to flow over all the weirs of the fishwayA total of 3,200 fishes in 4 orders, 10 families, 36 species; 260 crustaceans in 1 order, 3 families and 5 species; 5,685 aquatic insects in 7 orders, 28 families; and none of zooplankton were recorded in Shih-Gang Dam fishway and the upper and lower reaches stations. A total of 1,295 fish in 4 orders, 9 families, 27 species and 53 crustaceans in 1 order, 3 families, 5 species were recorded in the six surveys in the fishway.Comparing with the historical survey in which fish in 15 families, 47 species and crustaceans in 4 families, 9 species were reported, there are 5 new species added to records in this year, including Sicyopterus lagocephalus, Stiphodon atropurpureus, and Stiphodon percnopterygionus of the fishway, and Rhinogobius maculafasciatus and Coptodon zillii of the Chand Gung Bridge. Coptodon zillii are invasive species ,and the others are amphidromous species. There is new record of Puntius snyderi at the upstream of the auxiliary dam and invasive species Clarias batrachus at the fishway The new invasive species, Distoechodon compressus, which are first discovered in 2021, appeared at the upstream of the Chand Gung Bridge, the auxiliary dam, and the downstream of the Pifeng Bridge. Based on the above fact, Distoechodon compressus may have colonized and spread out to the upstream and downstream of the Shih-Gang Dam. In addition, Anguilla japonica, of which the last record was four years ago, appear again at the upstream of the auxiliary dam.According to the biodiversity indices, there is more biodiversity richness at the upstream of the Chand Gung Bridge, the downstream of the auxiliary dam, and the Pifeng Bridge than others. The possible cause might be that the habitats of the Chand Gung Bridge and the Pifeng Bridge are more natural. For the auxiliary dam, it is speculated that many species are trapped at the downstream of the auxiliary dam due to the incomplete new fishway. Ecological survey results show that this section of the river has low environmental pollution and abundant biological resources. The records include conservation species like Liobagrus formosanus, and Sinogastromyzon puliensis, and migratory species like Anguilla marmorata. There are also Onychostoma barbatulum, and Hemimyzon formosanus. which are more sensitive to water quality. It is believed that the ecosystem of this reach will be more complete if the fishway can be fully established in the future. The downstream of the Shih-Gang Dam is under the river stability and energy dissipation improvement construction. There was new construction carried out at the swamp beside the fishway, and the Pifeng Bridge has been totally demolished in 2023. The construction team has implemented conservation measures to avoid negative impacts on the species around the Shih-Gang Dam. Several conservation measures are employed at the construction area to maintain the fluency of the river, and the abundancy of the aquatic ecosystem. Currently, there isn’t abnormality of environment or aquatic species found in the construction area. As for the terrestrial animals, most of the species have strong mobility and are not living in the construction area. According to the fact mentioned above, it is assessed that there are little impact on the aquatic and terrestrial animals around the Shih-Gang Dam.Two batches of environmental education campaign including indoor and outdoor courses were conducted at October 20 and 21. According to the satisfaction questionnaires, most of the attendance are satisfied with both the indoor and outdoor courses, some are impressed by the live fish and shrimp and their propensity, and some suggested that there could be more fishway models, videos, insects, and other animals that live around the water included in the course content, and that the name of the name of the campaign should be more approachable to increase willingness to sign up for the campaign.The problems of jet flow of the Shih-Gang Dam fishway exit will affect the efficiency of fresh water creatures to trace upward. There is also a high downstream of the auxiliary dam without ecological corridor facility, which may have a negative impact on ecology. To address the problem, the ecological corridor design has been included in the upcoming energy dissipation dam and groundsill works projects, and it is expected to be improved the situation of the ecology of the reach around the Shih-Gang Dam.