Taichung City Government launched the first large-scale project in a century to clean the Sun Moon Lake in Taichung Park. The area is now fenced and all activities will be suspended throughout the duration of the project, including kayaking and access to the pavilion for photo taking. Despite the inconvenience, the majority of the visitors and residents are willing to give their support to the project and expressed their anticipation to seeing a clean and lively lake they can be proud of.
This is the first large-scale cleaning project for the Sun Moon Lake and the plan is to clean out the accumulated sludge and bring in live water, as well as building round-the-lake flow-intercepting ditch and soil discharging facility. Live water will be brought in from Hanxi (Han Creek) and “water bank” and pumping wells will be built to ensure year-round supply of live water. The facilities are expected to completely change the water quality and a sludge management system will be implemented to ensure minimum sludge deposit. The project is scheduled to be completed by end of the year and a clean lake can be expected, said Huang Yu-Lin, Director-General of Taichung City Construction Bureau
Sun Moon Lake in Taichung Park is a closed lake and the main sources of water are rainwater and 20 tons of underground water pumped into the lake every day. If we calculate the total capacity of the lake by 1800 tons, a full renewing cycle is 900 days. Since the volume of freshwater pumped into the lake is rather limited, sludge has been accumulated for years. In addition, large amount of excretions from fishes turtles, ducks and pigeons continue to deposit rich nutrients into the lake, eutrophication has turned the lake into a muddy and smelly pond, added Director-General Huang.
In view of which, the Construction Bureau planned this large-scale cleaning project to remove the deposited sludge from the bottom of the lake and designed facilities to bring in live water, intercept flow and discharge soil. A volume of 4000 tons of water will be channeled from Hanxi into the water purification pool under Gancheng Park and, after purification, part of the water will be discharged into Sun Moon Lake and the rest into Luchuan (Green River). A project to uncover Luchuan is also underway and this water source will become the source of live water for this river.
To prevent wastage of water resources, a “water bank” and underground water wells will also be built to supply for irrigation of Taichung Park and supplement Sun Moon Lake during dry season. After completion of the project, the lake water will be renewed once in five days to resolve the issues of water quality.
In addition, the Construction Bureau has also planned a round-the-lake flow intercepting system to prevent untreated water from entering the lake before purification. The flow intercepting system will prevent runoff surface water from entering and contaminating the lake during heavy rainfall.
Taichung Park is a century-old park. There are many old trees growing by the lake. These trees are treasures of the park. Therefore, we made every effort to prevent injuring the root systems of the trees. In the process, the Construction Bureau took each of the trees into consideration and designed part of the flow-intercepting ditches on the ground, instead of hiding underground. This is to ensure that the root systems of these trees are intact. We have also conducted a study on the ecosystem of the lake and we found that there are both foreign and domestic species of fishes in the lake. The City Government has engaged experts to separate the precious species of turtles and fishes from others to ensure that the ecosystem of Sun Moon Lake is protected to the best condition possible, said Director-General Huang.
Before the project began, the Construction Bureau made a survey on the volume of sludge to be dredged out the lake. Multiplying the thickness of the sludge by the area of the lake, approximately 2000 square meters of sludge will be dug out. This sludge is a nutrient-rich organic substance and highly suitable for planting. The Construction Bureau requested the contractor to store the sludge, which will be treated and used for soil improvement at the garden of the Central Park and the green corridor under the elevated railway.
Director-General Huang pointed out that the Taichung Park’s Sun Moon Lake project is a full-scale water quality improvement project. Comprehensive design, from sludge dredging, intercepting of untreated water, live water renewal to soil discharging facility, will drastically improve the water quality of the Sun Moon Lake, and the regular dredging mechanism will help to maintain deposit of sludge to the minimum. Such revitalizing plan marks the first in the history of Taichung Park. The City aims to bring back the splendor of Taichung Park through large-scale improvement of the environment, and the goal is to launch Taichung Park into its second century with sustainable designs that exceed the original.
The Sun Moon Lake dredging project was scheduled for completion by end of February next year. After negotiation between the Construction Bureau and the contractors, the project can be completed as early as end of this year. For safety, the lake will be fenced throughout the construction period and part of the entrances will be closed or managed by access control. The City appreciates the support and understanding from the city residents.