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Daxi Bridge - 2013 Award of Excellence in Quality for National Construction Projects

Located in Tainan City, Jiangjun Creek is a short river with mainstream only 24.2 km long. Belonging to the lower reaches of Zengwen creek, Jiangjun creek flows into the Taiwan Strait at Mashagou. Special hydrological environment gives rise to precious mangrove forest and Kandelia at the estuary of Jiangjun creek. The stretching Kandelia adds an elegant zen style to coastal Tainan under sunset.

Jiangjun creek brings Tainan people vibrant mangrove and Kandelia, as well as rich water resources. However, the water that ferries the boat is the same that swallows it up. In rainy seasons, Jiangjun creek causes flooding and water disasters for Tainan, making it a nightmare for people in Tainan. Therefore, Public Works Bureau of Tainan City Government in recent years actively has been making adjustments on a drainage system for Jiangjun creek. This drainage system flows through Guantian, Xiaying, Madou, Jiali, and Xuejia from upper to lower reaches. Jiangjun creek flows into a lagoon at Mashagou. The main drainage line is 11.1 km long, with the major branches of Mattau drainage system 11.9 km long and Jiali drainage system 8.2 km. Other 45 branches are 95 km long in total, with an area about 158.5 km2 for water collection. Jiangjun creek is located in Xiaying District, a flat-plain area in central Tainan city that belongs to Jianan Plain. The upper reach of Jiangjun creek flows through the southwestern part of Xiaying District, thereby being given a name of Daxi (big creek) by local residents.

According to statistics by Water Conservancy Department from Ministry of Economic Affairs in recent years, typhoon and torrential rains often get towns and villages along Jiangjun creek severely drowned. The torrential rain on June 12, 2005 caused a large scale submergence of that area, with water depth over 1 meter at the deepest spot. According to an analysis by Water Conservancy Department, the main reason for the flooding lies in insufficiency of the drainage section for Jiangjun creek that results in bottleneck and overflow. Furthermore, the drainage system of Jiangjun creek is located along a tidal river reach, where surface drainage is easily affected by water level , making it difficult for inland water to be drained away and thereby requiring more time to drain away the flood. Meanwhile, some branches of the drainage system have no water gates in their exits. Those parts that have water gates are mostly broken and need manual operation. When torrential rain occurs, the water gates are usually not easy to open due to its heavy weight and could not play up to its role of flood prevention in due time.

Moreover, if the cross ditch bridge is insufficient in draining away flood, it will block the water and cause a high level of water on the upper stream, worsening the flood. Daxi bridge, located on Madou drainage line over Jiangjun creek in Xiaying District, usually hinders the normal drainage of water when flooding takes place because of its low bridge bottom and narrow width. In this way, the river water overflows the bank and causes residents to suffer. Therefore, Tainan city government has been cooperating with Ministry of Economic Affairs on a “Treatment Plan for Flooding-prone Areas” by implementing a reconstruction for the Daxi bridge on the Madou drainage system. Special reconstruction on the bridge is to make the bridge bottom and span comply to the requirement for the Jiangjun creek drainage system.

The reconstruction project, with a total investment of 49 million, was officially completed on February 15, 2012. After typhoon season in the summer, we have already seen the effects of this reconstruction in reducing water disaster. In addition, all projects including the Jiangjun creek drainage system, estuary renovation project at the lower stream, and reconstruction of Huazong, Xizhou , and 56-1 Daxi bridges south of Madou drainage system have been completed and have significantly improved flooding of Jiangjun creek drainage basin. It not only increased 754 hectares of protected areas, but also protects the 23,000 residents, who can stop to worry about storms and flooding and can start to live and work in peace and contentment, promoting local economy and prosperity.