The prevention and control of stratum subsidence has been promoted so far, although the trend of continuous subsidence across Taiwan has been slowed (the total continuous subsidence area of ​​the implementation area has been reduced from 1,539 square kilometers in 2001 to 820 square kilometers in 2008; the maximum annual subsidence rate has been reduced from 17.6 cm in 2001 (Changhua area) ) Was reduced to 7.1 cm (Yunlin area) in 1997). However, due to the continuous subsidence of the stratum, it is prone to disasters. The elevation of the subsided area cannot be restored, and it is easy to cause flooding. Therefore, the prevention and control of stratum subsidence has actually involved "prevention "Continuous stratum subsidence-rational use of groundwater, conservation of the groundwater environment, and "treatment" of subsided areas. In order to effectively implement the prevention and control of stratum subsidence and the "treatment" of stratum subsidence areas, the Water Resources Department of the Ministry of Economic Affairs has proposed a "flood-prone area flood control plan", which will be handled in a comprehensive water management method, and the concept of land restoration will be expanded to handle " The Demonstration Project for Improving the Drainage Environment in Subsidence Areas" selects three severely subsidence areas in Chiayi and Yunlin as demonstration areas, and rehabilitates the environment with the three main axes of comprehensive water control, landform transformation and industrial adjustment. The "prevention" work in the subsidence area is integrated into the "Groundwater Conservation Management Plan" to promote implementation.

The main implementation areas of this project include Taipei, Yilan, Taoyuan, Changhua, Yunlin, Chiayi, Tainan, Kaohsiung, Pingtung and other stratum subsidence counties (cities); and other Yu counties (cities) that have been surveyed and assessed to have subsidence may be required. Area for groundwater conservation and management.

1. Increase the amount of groundwater replenishment and preserve the hydrogeological environment of groundwater.

2. Reduce the amount of groundwater pumping to avoid continuous deterioration of the groundwater environment.

3. Improve the efficiency of water well management and relieve the severity of stratum subsidence.

The work plan of this project will mainly focus on the implementation of groundwater replenishment, well management and disposal, and groundwater reduction and pumping work as the main axis, and will be combined with other plans or plans of the Water Resources Department of the headquarter (see Figure 1), and the competent authority will be responsible Planning and execution to effectively alleviate the deterioration of ground subsidence. The main execution strategies are:

1. Develop alternative sources of groundwater and reduce pumping of groundwater

2. Strengthen groundwater replenishment and restore groundwater environment

3. Implement well management and industrial planning to reduce pumping consumption

4. Continuous environmental monitoring to grasp the situation of stratum subsidence

5. Strengthen the promotion of organizational and legal research and training to improve management efficiency.

1. Promote the construction of surface water storage facilities and water supply systems in the Yunlin area of ​​Changhua to increase the available surface water supply and utilization efficiency, effectively improve the flexibility of regional water resources scheduling, reduce the potential for groundwater pumping, and slow the rate of ground subsidence.

2. Promote the implementation of the planning, design and construction of the groundwater replenishment area in the Yunlin area of ​​Changhua, in conjunction with the construction of water storage facilities, which can increase the amount of groundwater replenishment, raise the groundwater level and maintain the sustainable operation of the groundwater environment.

3. Face and solve the problem of a large number of illegal water wells, stop new illegal wells, dispose of existing illegal wells in stages, and categorize and fill existing illegal wells to lay a foundation for water rights management.

4. Continue to carry out the observation and testing of basic environmental data, collect long-term and complete environmental background data, and serve as an important reference for the development, review and adjustment of related management measures such as the follow-up study of stratum subsidence prevention measures and joint use of water resources by relevant units. To achieve the goal of conservation and sustainable use of land, water resources and environment.

5. Continue to review the delineated scopes of "groundwater control zones" and "severely subsided areas", and benefit related units to carry out restoration work and control measures to implement control of various land use behaviors, so that the natural environment can be recuperated.

6. Carry out relevant management measures and regulations and research work to facilitate the implementation of environmentally sensitive locations in the future to control the use of environmentally sensitive locations, so as to gradually achieve the goals of ground subsidence prevention and land preservation.

1. By 2014, at least 30 well surveys in towns and cities have been completed.。

2. Completed the closure or sealing of a total of 153 water wells and 2,000 private water wells of the Water Supply Company, Changhua and Yunlin Farmland Water Conservancy Association.

3. Complete 4 groundwater replenishment plans and install related facilities.

4. Increase the supply of surface water in the Yunlin area of ​​Changhua by about 60 million tons/year, the recharge of groundwater by about 35 million tons/year, and the reduction of groundwater by 2 million tons/year.

5. The groundwater replenishment volume in Pingtung area reaches approximately 120 million tons per year.

6. As of 2014, the maximum average compression rate of deep formations in the implementation area shall be controlled within 5 cm/year.

7. The area of ​​continuous subsidence in the implementation area is less than 800 square kilometers.

8. Maintain the existing 672 groundwater level observation wells to function normally. At least 60 observation wells in the groundwater observation network have been replaced with new ones, 72 wells have been repaired, and 250 wells have been cleaned and maintained.

9. Complete the hydrogeological drilling and supplementary investigation of the groundwater area in Zone 3, and reinforce the new 70 groundwater level observation wells.。

10. Complete the evaluation, construction and improvement of the remote transmission system for groundwater level observation data in at least 3 groundwater areas; and the detection and correction of the elevation of the observation well top in the stratum subsidence area.

11. Complete the three-dimensional hydrogeological structure of at least 4 groundwater areas; establish regional management water levels and operation indicators for at least 7 groundwater areas.