The second phase of groundwater conservation management and stratum subsidence prevention and control plan (2015~2020)

This plan is a continuous medium and long-term plan, and the preliminary plan "Groundwater Conservation Management and Stratigraphic Subsidence Prevention (2009~2014)" will end in 2014. The work item of this project in the Yunlin Changhua area is based on the "Concrete Solution and Action Plan for Stratigraphic Subsidence in the Yunzhang Area" as the upper-level plan, and the overall work promotes the disclosure of "Continuous Subsidence Related Monitoring and Investigation" and "Strengthening of Well Management" "Strengthen technical and administrative management" and "strengthen groundwater replenishment" four major strategies. According to various strategies, the current handling situation is described below.

1. Continuous stratum subsidence related monitoring investigation

()(1) Groundwater observation network operation, stratum subsidence detection system update, and stratum subsidence warning

1. The Yunzhang area has continued to maintain 189 groundwater level observation wells to function normally; in addition, 747 groundwater observation wells have been constructed throughout Taiwan to grasp the changes in the groundwater environment.

2. Yunzhang regional level inspection work, the Yunlin and Changhua regional level network inspection work was completed on June 4 and 8 respectively, and the inspection results inspection work was completed on June 22 and July 16 respectively; continuous processing 32 ground traps, 17 GPS fixed stations and 4 deep leveling piles for the maintenance of soft and hardware equipment and the collection of monitoring data; and 3 GPS fixed stations were completed at the end of March (Sihu Township, Yunlin County, Baozhong The construction work of the township, Dongshi Township) was completed by the end of May; the construction of the 300-meter stratum subsidence monitoring well of Nanguang Elementary School, Sihu Township, Yunlin County was completed on June 4, and the acceptance was completed on June 25.

3. In 2018, Dongshi Township, Sihu Township, Baozhong Township, Yuanchang Township, Huwei Township (Annan Elementary School, Nanguang Elementary School, Longyan Elementary School, Shannei Elementary School, Zhengmin Elementary School) and Chiayi County 6 fixed dual-frequency GPS tracking stations have been set up in Jiaoxiang (Suantou Elementary School Tanqian Branch); in addition, magnetic ring layered strata have been set up in Sihu Township and Dongshi Township (Nanguang Elementary School, Annan Elementary School) in Yunlin County Two monitoring wells were subsided, and one in Tainan Annan District (Chengda Hydraulic Engineering Institute) was updated.

4. Based on geographic statistical divisions (correlation of groundwater level), the Water Resources Department plans to design wells for areas with low groundwater level correlations in specific aquifers (representing that the groundwater conditions of the division are less controllable). The first and second water contain The layer may be more significantly affected by rainfall replenishment, so geographic statistics, hydrogeological and sub-catchment areas are used to overlay maps and data, and compare the locations of existing observation wells and schools, and provide suggestions for supplementing the observation network; and For the third and fourth aquifers, because of lower management requirements and higher costs for well setting and follow-up maintenance and management, only suggestions for supplementing the observation network are given for geographic statistical subregions. After evaluation, 74 observation wells are suggested for supplementation in the launching areas of Taiwan, including 12 in the Taipei Basin, 14 in the Taoyuan Zhongli platform, 6 in the coastal area of ​​Hsinchu Miaoli, 3 Zhuoshuixi alluvial fans, 23 in the Jianan Plain, and Ping There are 8 locations in the East Plain, 2 locations in the Huadong Rift Valley, and 6 locations in the Lanyang Plain.

(2) In 2017, the inspection and results of the benchmarking points:

1. The significant subsidence area of the whole Taiwan decreased from 1529.2 square kilometers in 2001 to 326.7 square kilometers in 2014; however, from the end of 2014 to 2015, it suffered 67 years of severe drought. The amount of groundwater recharge decreased and the amount of water pumped increased. The area increased by 819.8 square kilometers. In the second half of 2015 and the first half of 2016, rainfall increased and groundwater recharge increased, and the subsidence slowed down. The area was 106.4 square kilometers. In 2017, the area was 395 square kilometers. The changes in the maximum average subsidence rate and significant subsidence area in Changhua, Yunlin, Chiayi and Pingtung from 2015 to 2017 are shown in Table 2-3.1.

Table 2-3.1   Changhua, Yunlin, Chiayi, Pingtung area from 2015 to 2017 maximum average subsidence rate and significant changes in subsidence area

(3) Results of the stratum subsidence across Taiwan in 2017

The significant subsidence area of the whole Taiwan decreased from 1529.2 square kilometers in 2001 to 326.7 square kilometers in 2014; but from the end of 2014 to 2015, it suffered 67 years of severe drought. The amount of groundwater recharge decreased and the pumping volume increased. The area increased to 819.8 square kilometers in 2015. Km. In the second half of 2015 and the first half of 2016, rainfall increased and groundwater recharge increased, and the subsidence slowed down. The area was 106.4 square kilometers. In 2017, the area was 395 square kilometers.

2. Strengthen well management

(1) Handling water well disposal operations

1. According to the second phase of the groundwater conservation management and stratum subsidence prevention and control plan, the target for filling wells in 2018 is 800. As of November 2018, the Water Resources Department of the Ministry of Statistics and Economic Affairs has subsidized Taipei City, New Taipei City, Taoyuan County, Miaoli County, Taichung City, Changhua County, Yunlin County, Chiayi County, Chiayi City, Tainan City, Kaohsiung City, Pingtung County, Yilan A total of 14 groundwater control areas, county and city governments, including counties and Penghu County, have disposed of 750 (newly added 90 illegal water wells, 660 existing illegal and legal water wells), of which 280 are planned for disposal in Yunzhang area, and others Counties and cities plan to dispose of 470, and it is scheduled to reach the target of 800 for the second phase of groundwater conservation by the end of the year.

(2) Promote re-inspection and counseling of piped water wells

1. The Changhua County Government and the Yunlin County Government completed identification tags for 130,414 and 126,396 piped water wells respectively in 2016, a total of 256,810, and started to conduct guidance and issuance operations in 2017.

2. In 2018, Changhua County completed the preparation of the county's management water well documents and completed 10,000 legal counseling. In 2018, Yunlin County handled the legal counseling in Huwei Town, Tuku Town, and Yuanchang Township. As of October, 21,185 cases have been received and 19,098 cases have been investigated.

3. The progress of other counties and cities in handling water wells in 2018 is as follows::

(1) The Kaohsiung City Government has completed the acceptance of the application for tubed water wells on September 30, 2018, and received a total of more than 17,000 pieces. The legal time for follow-up review and guidance is still under planning.
(2) From October 2016 to June 106, the Yilan County Government completed the application and review of the acceptance and re-inspection of the piped water wells, and then started the legal operation in July 2018.
(3) Taichung City's plan to promote water well management will be announced and accepted from May 2017 to December 2018. The legal time for follow-up review and guidance is still under planning.
(4) The Pingtung County Government plans to handle the application, review and counseling of animal husbandry water wells and legal factory water wells for 4 years from July 2017 to July 2021 and June 2018 to June 111 respectively. operation.

Table 2-3.2 Statistics on the number of plugged wells of each subsidized local government in 2018

3. Strengthen technical and administrative management

(1) Continuous staff service and horizontal contact

1. The Ministry of Economic Affairs is appointed by the Water Resources Department as the staff to promote the prevention and control of stratum subsidence. The service team provides professional skills and manpower to assist the Department of Water Resources in preparing for the "Committee on the Promotion of Stratigraphic Subsidence Prevention and Control of the Ministry of Economic Affairs", the "Report on the Prevention and Control of Stratigraphic Subsidence", and the "Ministry of Economic Affairs" Meeting of the Working Group on Subsidence Prevention and Control."

2. Participate in stratum subsidence prevention and control meetings held by various central ministries such as the Council of Agriculture, the Ministry of Interior, and the Ministry of Transport and local agencies in the subsidence area of ​​each level, and assist in supporting the operation of the central inter-ministerial (horizontal) contact integration and division of labor cooperation promotion mechanism Relevant staff, and master local work information and direction, provide reference for the adjustment of the policy direction of relevant central ministries, and promote a regular (vertical) coordination mechanism between the central and local governments.

3. The above-mentioned stratum subsidence prevention and control conferences held in 2018 are shown in Table 2-1.1.

(2) Relevant regulations and operational regulations for training

1. The draft amendment to Article 22 of the Water Conservancy Law is currently continuing to communicate with the relevant stakeholders of this amendment. Once a consensus is reached, the amendment will be proposed in a timely manner, and subsequent amendments to the draft will be fully promoted.

2. On March 12, 2018, the water rights and water use scope management system commissioned plan work implementation plan review meeting was passed, and on July 23, the water rights and water use scope management system commissioned plan mid-term report review meeting was passed.

3. Based on the conservation of groundwater resources and the protection of the rights and interests of legal drilling operators, the Water Resources Department is now studying and amending Article 93-1 of the Water Conservancy Law to increase the penalties for illegal drilling.

Fourth, strengthen groundwater recharge

(1) Promote comprehensive evaluation of groundwater recharge work and recharge benefits

1. Simple facility project for groundwater replenishment in Zhuoshuixi Channel:

(1) In 2018, based on the operating records of the Jiji barrage and the rainfall and evaporation data, it was estimated that the groundwater replenishment volume from January to September 2018 was 602.5 million tons, the 12 existing flood detention ponds in Yunzhang were 53.1 million tons, and the Hushan reservoir was 0.103. Billion tons, totaling 125.9 million tons.
(2) At this stage, the installation of water level monitoring equipment for 6 detention ponds has been completed, which will be used as the basis for estimation and verification of the refill volume using measured data in the detention pond in this (2018) year.

2. The groundwater recharge lake of Zhuoshuixi high beach:

(1) In 2018, the "Zhushui River Dust Prevention and Improvement Action Plan" will be used as an alternative to the original plan, which can increase the amount of groundwater recharge through beach water coverage measures (water storage ponds, water diversion and sand interception channels).
(2) At present, the Fourth Rivers Bureau has obtained relevant information on beach storage ponds (including water-retaining embankment construction), water covering measures, and water diversion and sand interception channel engineering planning and construction content in the aforementioned Zhuoshui River dust improvement work. The site survey was carried out on October 9, 2018, and relevant documents and information will be compiled in the follow-up to process groundwater recharge assessment work.

3. Pingtung Grand Chaozhou Groundwater Recharge Lake Phase 1 Project:

(1) Preliminary benefit evaluation of the implementation results of the first phase of the project: After the completion of the monitoring center in 2017, the water diversion will be officially operated from July 25th to October 21st. The monitoring system records show that the water is diverted for 400 hours and the water enters the first sedimentation tank. The refill volume is 16.8 million tons. The infiltration rate is estimated based on the lake water level record. The infiltration rate of the first sedimentation tank is 1~5m/day, with an average of about 3m/day. The daily refill volume is 520,000 tons, and the lake water drops daily. 4 meters.
(2) The first phase of the project implementation plan was originally scheduled to be completed on December 31, 2015, and the implementation period of the revised plan was extended to December 31, 2017. However, during the execution of the second sedimentation tank excavation project, due to the large volume of earth and stone transportation, the public expressed hope that the transportation would be stopped on holidays, so it was actually completed in June 2018.
(3) Groundwater replenishment in the Chaozhou recharge lake area has a certain degree of contribution to the rise of the water level in the Pingnan area (especially the coastal strata subsidence and seawater intrusion area). In the future, if the water source first passes through the sedimentation tank and then enters the recharge lake, the recharge efficiency will be improved. It can be greatly improved. After the development of the whole area in the future, it is estimated that about 150 million cubic meters of groundwater can be recharged annually. It is expected to conserve the underground aquifer in the southern Pingtung Plain and effectively improve the subsidence and seawater intrusion in coastal areas.

(2) Planning for groundwater replenishment work

1. Simple facility project for groundwater replenishment in Zhuoshui River Channel

2. Strengthen the assessment work of existing water conservancy facilities to increase the amount of groundwater recharge, and cooperate with the river improvement project to handle simple recharge facilities for the Zhuoshui River channel at an appropriate location.

3. Discuss with the Water Conservancy Association to set up farm ponds or artificial lakes next to the irrigation ditch. In addition to increasing the irrigation water regulation capacity, it can also increase the amount of groundwater recharge. The plan initially estimates that the annual recharge per hectare can reach 650,000 tons.

4. Promote the Gukeng artificial lake development plan. According to the current artificial lake planning proposal, the Gukeng artificial lake develops an area of ​​294 hectares, with an effective water storage capacity of 2.32 million tons, and groundwater infiltration capacity of approximately 9.44 million tons per year.