| 英文計畫摘要 | In 1930, Japanese hydraulic engineer, Yoichi Hatta, built the Chia-Nan Canal as a way to connect the Choshui River and the Tsengwen River, allowing allocation of water systems during drought periods. Unfortunately, the inverted siphon that was in Beigang River was damaged by the scouring. Therefore, the project involoves either repairing the inverted siphon or constructing an alternative water delivery facility. It is possible to reduce the irrigation water of the Zengwen-Wusantou reservoir system and increase reservoir storage by sending surplus water from Choshui River to Chia-Nan Irrigation. In addition, if water from the Choshui River still cannot satisfy every demand which intakes from Jiji Weir, we can dispatch water from Tsengwen-Wushantou Reservoir System to Yunlin Irrigation to reduce the irrigation water shortage rate. The benefit of the two-way allocation can improve the stability of water supply in Yunlin, Chiayi and Tainan.
1. In order to determine whether there is surplus water to dispatch, we should first analyze the water supply potential of the Choshui River system and the Tsengwen River system. As part of our efforts to improve the overall water supply system, we must review the water supply capacity of Hushan Reservoir, which is built in partnership with Jiji Weir.
2. According to Jiji Weir operating record from 2002 to 2020, the inflow of Jiji Weir is 4.44 billion cubic meter per year while the intake of Douliu Weir is 66 million cubic meter. And the agricultural, public and industrial water supply are 1.78 billion, 34 million and 101 million cubic meter per year.
3. According to Tsengwen Reservoir operating record from 2002 to 2020, the inflow of Tsengwen Reservoir is 1.23 billion cubic meter per year, and the agricultural, public and industrial water supply are 568 million, 141 million and 19 million cubic meter per year.
4. According to “Reviewing Master Plan of Water Resources Management for Central Taiwan” by WRA, MOEA, which was published in 2019, the water supply capacity of Hushan Reservoir is 432,000 cubic meter per day. In this project, the lastest water supply capacity analyzed by using the lastest hydrology data and reservoir storge is 427,000 cubic meter per day, the reason why the water supply capacity is reduced is due to the drought events these years. Thus, we suggest that the water supply capacity of Hushan Reservoir should remain 432,000 cubic meter per day.
5. After analyzing the water supply potential of both river system, we examine not only the water sources of Choshui River dispatching to Dongshi branch line irrigation area, but also the water sources of Tsengwen River dispatching to Beigang branch line irrigation area. According to result, the former can supply an average quantity of 955 million cubic meter of water per year, while the latter can only provide 267 million cubic meter. The water supply benefits are vastly different.
6. This dispatch plan will be pushed forward if irrigation channels are repaired; therefore, a number of projects will be undertaken to improve irrigation channels. As for the Beigang River crossing section, the project of an inverted siphon was evaluated and implemented. According to calculations, the total cost is NT$2.33 billion, striving to become part of the official budget.
7. It is recommended that, when the follow-up plan is implemented, relevant units should hold regular consultation meetings to discuss and arrange the start-up time, which is conducive to the promotion and smooth implementation of the plan. |