The Yunlin area of ​​Changhua is an important agricultural county for me. It has an area of ​​123,000 hectares of arable land. More rice with higher economic value is grown. Because it is a high water-consuming crop, the ground water source cannot fully supply the water it needs. For a long time, it has been due to the implementation of the rotation system to deploy extremely limited surface water resources. However, farmers in non-irrigation areas and outside the irrigation areas still plant more rice based on livelihood considerations and draw groundwater by themselves. In the Changyun area, where the ground water source no longer meets the demand for agricultural irrigation water and relies on groundwater injection, the water for breeding, domestic and industrial is also competing with groundwater sources. The relevant research results of the Zhuoshuixi alluvial fan over the years show that Changhua Yun The annual amount of groundwater pumped in the forest area is estimated to be about 1.2 billion cubic meters, and the annual excess pumping volume is about 240 million cubic meters. Years of excessive pumping of groundwater is one of the main reasons for the stratum subsidence in the Yunlin area of ​​Changhua.

According to the survey results of stratum subsidence in recent years, Changhua County’s Dacheng Township still has a subsidence rate of more than 10 cm per year, while the center of Yunlin County’s subsidence gradually moves from coastal areas to inland areas such as Tuku and Yuanchang. On July 2, 2004, Typhoon Mintouli invaded the Taiwan, and the torrential rain brought by the peripheral circulation caused frequent flooding disasters in 20 towns and cities in Yunlin County. The flooding depth of coastal towns and towns reached 60 to 70 cm for more than 20 days. It can be seen that the subsidence of the stratum has made the drainage system in Yunlin unable to function; and the high-speed railway that will be completed soon passes through the subsidence of the stratum of Yunlin, and future traffic problems need to be clarified.

In order to alleviate the impact of stratum subsidence in Yunlin County's Tuku and Yuanchang and other areas on the operation of high-speed railways, the Ministry of Economic Affairs, in conjunction with relevant ministries, will actively discuss prevention and control measures for the problems of stratum subsidence. On April 28, 2004, the Ministry of Economic Affairs When briefing the Executive Yuan Director Youqian on the issue of "Flatland landscape afforestation policy and the prevention of stratum subsidence along the high-speed rail in Yunlin area", the President Youqian instructed: "Regarding the Ministry of Economic Affairs' plan to move first within 3 kilometers along the high-speed rail of Yunlin County For the publicly-owned and legal water wells section, the Ministry of Economic Affairs is requested to review and develop specific feasible plans and procedures for the sealing, relocation, subsidies, and water source responsiveness of the Taiwan Water Supply Company, Yunlin Farmland Water Conservancy Association and Taiwan Sugar Company. The Ministry of Economic Affairs and the Executive Yuan will be responsible for coordinating, coordinating, handling and supervising the assessment.” To establish the policy direction for the disposal of wells belonging to the Taiwan Provincial Water Supply Company, Yunlin Farmland Water Conservancy Association and Taiwan Sugar Company within 3 kilometers along the high-speed rail. The committee intends to formulate this implementation plan to submit it to the Executive Yuan in accordance with the procedures, so that it will be implemented after approval.

1. Reduce the amount of groundwater pumped along the high-speed railway in Yunlin County, and make the groundwater level rise.

2. Relieve the rate of stratum subsidence along the high-speed rail in Yunlin County and reduce the impact of stratum subsidence on the operation of high-speed rail.

1. Disposal of the water wells belonging to Taiwan Sugar Company As a water well of Taiwan Sugar Company located within 3 kilometers along the high-speed rail line in Yunlin area, there are only 2 water wells left, and the amount of groundwater pumping is small, and it is a separate system. The matching water wells must be re-drilled when moving. The reconstruction of the water supply system requires considerable funding and does not meet the economic benefits. After evaluation, it is planned to temporarily not seal and relocate the wells. Instead, reduce the amount of pumping and strengthen the monitoring of the amount of subsidence. If the situation deteriorates, immediately stop it Go through.

2. Yunlin Farmland Water Conservancy Association's water wells are closed and moved. Some Yunlin Farmland Water Conservancy Association has 69 wells within 3 kilometers along the high-speed rail. The disposal methods are evaluated and analyzed by the Ministry of Economic Affairs and the Executive Yuan Committee of Agriculture. The principle of joint deployment with groundwater is to plan water well sealing, migration and decommissioning, funding requirements, and promotion schedules, etc., and research and develop a water well sealing and relocation plan. The detailed plan is shown in Annex 1. After considering the water source allocation status of each well after sealing and filling, 15 wells will be kept in place for continuous irrigation, and the other 54 wells will be selected according to the condition of the well body and the reliability of the allocated water source. The mouth is disabled. In addition, in order to supplement the water source to cope with the water supply gap after the 54 wells are closed or stopped, we will cooperate with the water diversion facility project and the trunk branch and branch channel improvement project to reduce the leakage loss of the aging channel, and the expansion channel project to use the water supply source deployment Transport, and cooperate with the strengthening of irrigation management and facility maintenance to save surface water usage in the water supply area of ​​the Water Conservancy Association. The saved water can be used for farmland within 3 kilometers and will be added to the fan roof outside the groundwater control zone. 13 new wells were drilled in the area to supplement the insufficient water source after the groundwater wells were suspended. After the completion of the related facilities in 2008, the project will reduce the overall groundwater pumping consumption within 3 kilometers of the Yunlin County high-speed rail by 6-10 million cubic meters per year, and the groundwater level will rise by about 10 to 65 cm, which will relieve stratum subsidence rate. This implementation plan requires approximately NT$363.95 million from 1994 to 1997. In addition, the annual expenditure required for continuous irrigation management and maintenance and surface water allocation since 1998 is NT$11.40 million. , It shall be prepared year by year in the public construction related budget line of the Agricultural Committee of the Executive Yuan, and shall be implemented by the Yunlin Farmland Water Conservancy Association.

 

3. The water well closure part of the Taiwan Provincial Water Supply Company This case was negotiated by the Water Resources Department of the Ministry of Economic Affairs and the Taiwan Provincial Water Supply Company and other related units. According to the "Jiji River Weir Downstream Water Supply Project", the surface water was completed in June of this (2005). The process of the stable water supply of the supply system and the priority of the potential areas of stratum subsidence, etc., in addition to the draft treatment plan for the wells within 3 kilometers along the Yunlin County high-speed rail, and the Yunlin and Changhua 3 kilometers away from the Yunlin County high-speed rail The water wells in the water supply area of ​​the original Jiji river weir downstream water supply project in groundwater control areas such as Chiayi County and other groundwater control areas have also drawn up the amount of water that can be shut down, the schedule and the principles of shut down. The detailed plan is shown in Annex 2. The Taiwan Provincial Water Supply Company has 16 tap water source wells located within 3 kilometers of the Yunlin County high-speed rail line. Among them, there are 1 for Beigang Operation, 11 for Turk Operation, and 4 for Lunbei Operation. Except for the 2 tap water source wells (1 each in the Beigang Operation Office and the Turbine Operation Office) that can be immediately sealed and filled after the implementation plan is approved, the downstream water supply project of the Tujiji River Barrage is planned in June of this (94) After the completion of the month, when the Linnei Water Purification Plant can provide stable water supply, the 10 tap water source wells of the Turret Operation Station can be disabled, and the other 4 wells in the Lunbei Operation Office of Erlun Township (the disabled water volume is about 3,800 CDM). Based on relevant monitoring data, it is determined that the potential of geological soil compression in this area is small, and the potential of stratum subsidence is also small, and because the township is not in the water supply area of ​​the "Jiji Barrage Downstream Tap Water Project", if you want to stop To use these 4 water wells, it is necessary to extend the pipeline to Erlun Township. The project cost is about 230 million yuan. After considering that the water volume of these 4 water wells is only about 3,800 CDM, and the stratum subsidence potential is small. If you want to stop using it, you will still need to spend a lot of money to handle related pipeline projects. If it does not meet the economic benefits and other factors, it will not be used for the time being. Instead, it will continue to track the actual formation subsidence near the 4 wells and review them regularly; if there is a deterioration Immediately stop the operation and stop the operation after the completion of the Hushan Reservoir and the downstream Xiluo Town to Erlun Township pipeline project. The relevant implementation schedule, outage water volume and number of outage wells are detailed in the following table.

After the plan is approved, a control mechanism will be established when each well is reopened, and a monitoring plan will be established. In addition to monitoring the implementation of the plan, the groundwater background data in the planned area will be established before implementation, and groundwater changes will be tracked. Analyze the effectiveness of this project.

1. In conjunction with the development of surface water sources and the joint deployment and utilization of regional surface and groundwater, it is expected that after the completion of this implementation plan, it is expected to reduce about 11-15 million cubic meters within 3 kilometers of the Yunlin County high-speed rail and about 5,100-5,500 in Zhangyunjia. The amount of groundwater pumped within 10,000 cubic meters.

2. After the completion of this implementation plan, the groundwater level within 3 kilometers along the high-speed rail can be effectively recovered, which will ease the rate of stratum subsidence along the high-speed rail and reduce the impact of stratum subsidence on the operation of the high-speed rail.