圖書典藏及影音數位平台

為能明瞭石岡壩魚道及其上下游水域生態資源之變化，本計畫工作以每月採集所得的魚蝦類種類與數量，經由豐度、歧異度與均勻度及環境因子相關性等統計分析，除瞭解利用石岡壩魚道的生物種類、利用時機，與石岡壩對洄游生物的影響之外，並探討有何種生物利用魚道進行洄游，與生物利用魚道的季節，並提出石岡壩既有工程期間，對生物使用石岡壩魚道的狀況與周遭水域生態變動影響程度之評估，以供工程施作時應有的因應措施與對策。 因此，本計畫工作項目包括：(ㄧ)長庚橋至埤豐橋（含魚道本體）水域生態及洄游生物監測，進行統計分析，並建立石岡壩上下游和魚道之水域生物物種名錄。(二)蒐集分析長庚橋與埤豐橋間(含魚道本體)歷年水文水理(流量、流速)與水質狀況，並進行水質(含水溫、溶氧量、總溶解固體、pH值、導電度、氨氮等)、流量、流速之量測與監測。(三)以記錄魚隻由下游使用魚道上溯至上游的個體之水下攝影。(四)辦理研習與解說推廣活動，讓民眾了解石岡壩水域生物資源，進而愛護生態環境。(五)評估石岡壩既有工程中水域生態體系變化的有關生態保育措施。(六)工作報告及成果報告編撰印製等。

This project completed the ecological monitoring of fishway and the upper and lower reaches of Shih-Gang Dam on March 9-10, June 9-10, August 18-19, and November 11-12, and two additional investigations of Shih-Gang Damfishway were completed on April 29 and September 29. A total of 2,831 fishes in 4 orders, 9 families, 28 species; 277 crustaceans in 1 order, 2 families and 3species; 8,131 aquatic insects in 7 orders, 23 families; and none of zooplanktonwere recorded in Shih-Gang Dam fishway and the upper and lower reaches stations. A total of 1,211 fish in 3 orders, 5 families, 23 species and 165 crustaceans in 1 order, 2 families, 3 species were recorded in the six surveys in the 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, Sinogastromyzon puliensis, and migratory species like Anguilla marmorata, Sicyopterus japonicus, Macrobrachium latimanus, as well as the more sensitive to water quality, like Onychostoma barbatulum, Hemimyzon formosanus, have also recorded, if the fishway can be fully established in the future, it is believed that the ecosystem of this section of the river will be more complete.After comparing the fish survey with the historical records, this project has newly added 1 species of fish records: Distoechodon compressus. In addition, Onychostoma alticorpus and Spinibarbus hollandi that have been recorded since 107 are invasive species native to the eastern and southern watersheds of Taiwan. According to the record results this year, it can be confirmed that Onychostoma alticorpus and Spinibarbus hollandi have invaded to large scales.After investigation of this project, it is found that the entrance and the first section of the fishway have been siltated to form a slow watershed type. The rest pool of the first section is also overgrown with vegetation. In April, the water volume is extremely small. The bottom holes in section one and section two are blocked by mud and sand. Since there has been a problem of blockage between the fishway entrance and the first section of the fishway in the past, it is mainly due to the backwater of the stilling basin. If the stilling basin is too high and the flow of the fishway is insufficient, the fishway entrance may be silted. It is recommended to pay attention to the flow conditions of this section in the future, and increase the discharge flow of the fishway when necessary, so that the silt in the culvert section at the entrance of the fishway can be discharged out of the stilling basin as much as possible. The problems of outlet siltation and jet flow also affect the ability of fish, shrimp and crabs to trace upward. There is also a high drop downstream of the secondary dam, because there is no ecological corridor facility, it will temporarily cause a certain degree of ecological impact.In response to this problem, the related ecological corridor design has been included in the upcoming energy dissipation dam and groundsill works projects, and it is expected to be improved.