Southern Region Water Resources Branch, WRA, WOEASouthern Region Water Resources Branch, WRA, WOEA

I. Background
To address the challenges brought by climate change, protect against flooding, and manage aquatic resources and ecosystems, Taiwan government has proposed a major water infrastructure plan as part of the Forward-looking Infrastructure Development Program approved on April 5, 2017. The water infrastructure plan will combine resources across government agencies to build quality aquatic environments that provide reliable water supplies, clean drinking water, stronger flood defenses and accessible waterfront spaces. This Baihe Reservoir Further Improvement Plan (Phase I) is one Water Environments Project of the Forward-looking Infrastructure Development Program mentioned above.

II. Content and Budget
There are 4 subprojects in the Baihe Reservoir Further Improvement Plan (Phase I) including the “Sediment Bypass Tunnel Project”, the “Reservoir Dredging Project”, the “Hydraulic Dredging by Pumping Project”, and the “Baishuixi River Bridge Reconstruction Project”. The total budget of this further improvement plan is 1.77 billion NTD.

III. Economy and Benefits Analysis
Since it is hard to develop any new reservoir projects in Taiwan now, the existing reservoirs must be activated and improved to ensure a stable water supply in the southern region. Therefore, the goal of this Baihe reservoir further improvement plan (Phase I) is to restore storage capacity to 12.5 million cubic meter. The benefits of this plan include improvements of water resources management capacity in the southern region, increases in crop yield, and also sightseeing. The calculated benefit ratio is about 1.13, which indicates that this plan is worth doing.

IV. Project Schedule
During the implementation period, a rolling management will be adopted to review and adjust the work items and contents to make progress towards the plan goal. The content and funds for each year will also be verified. A table of the detailed work items and schedules are shown below.

V. Conclusion
Water resources are essential for economic growth, and also vital for the preservation of Taiwan’s security and quality of life. The Forward-looking Infrastructure Development Program is designed to protect citizens against water-related disasters, create a safe and livable environment, and provide reliable water supplies. To increase resilient to the effects of climate change, this further improvement plan is to maintain effective storage capacities of Baihe reservoirs and manage water resources to afford a stable water environment in the southern region of Taiwan.

Water in Tainan is mainly supplied by Zengwen, Wushantou and Nanhua Reservoirs. About 920,000 tons of domestic water and industrial water are consumed daily. 40% comes from Zengwen Reservoir and Wushantou Reservoir, and the other 60% comes from Nanhua Reservoir. Zengwen Reservoir has to use the Wushanling tunnel to convey water to Wushantou Reservoir to meet the demand for all water uses. In terms of domestic and industrial water demand in Kaohsiung, approximately 70% is supplied by Gaoping river weir due to a lack of large storage facilities. However, a stable water supply is sensitive to the river’s turbidity, especially after torrential rains. Therefore, up to 500,000 CMD (m3/day) of backup raw water coming from Nanhua Reservoir via the existing Nanhua/Gaoping interconnecting pipeline provides support for Kaohsiung once the turbidity of Gaoping river exceeds the treatment standard. Nanhua Reservoir provides backup raw water support for Kaohsiung and supplies 60% of daily water consumption in Tainan despite having less than 17% of the total capacity of Zengwen and Wushantou reservoirs combined. Because a drought or emergency would cause a water shortage, it is necessary to add another raw water backup pipeline in current Tainan and Kaohsiung allocation area to increase water support system capacity.

In order to solve these restrictions above and improve the water supply in southern Taiwan, the Southern Region Water Resources Branch puts forward the Zengwen/Nanhua Interconnecting Pipeline Project. After the project is completed, a backup pipeline to support water can be added to connect water resources in Tainan and Kaohsiung cities. More flexibility in water dispatch will reduce the risk of water shortage in southern Taiwan. The pipeline of the project acts like a catheter that supplies life-saving resources promptly and gives water users in southern Taiwan security and peace of mind.

Fig.1 Current Water Supply in Sothern Taiwan (2018)

Scope Of The Project

The pipeline starts at the penstock of power plant in the left abutment of Zengwen dam, and runs through Zengwen Reservoir area and Nansi, Yujing, and Nanhua districts in the east of Tainan city. It connects to 2 facilities, the Nanhua Purification Plant and the existing Nanhua/Gaoping interconnecting pipeline. The pipeline in this project extends over a total distance of 25km. The design discharge capacity is 800,000 CMD. The pipeline sends water by gravity, which makes it an environmentally friendly choice that doesn’t need any other energy to transport water. NT$12 billion will be invested in this project. The project will commence in 2019 and reach completion in 2024.

Fig.2 Route Map of the Project