Following President Lee's instructions, the Taiwan Provincial Government made seven key decisions after discussions. The Department of Construction directed the Yunlin Irrigation Association to take immediate action. Recognizing the importance of President Lee's directive on "diverting water from north to south," the provincial chairman urged prompt planning and the start of construction.

1. The North-South Water Diversion Project was deemed feasible and would become even more valuable once the Jiji Joint Water Diversion Project was completed.
2. The Yunlin Irrigation Association promptly dispatched technical personnel to estimate the costs for dredging the inverted siphon. Once the project costs were finalized, a report was submitted to the provincial chairman for approval. Upon authorization, funds were allocated from the provincial contingency budget, and the Yunlin Irrigation Association was tasked with executing the project.
3. To achieve the goal of diverting water from the north to the south and enhance the interconnection between the Northern Main Canal of the Wushantou system and the Zhuo Main Canal, priority was given to renovating and restoring existing facilities, followed by detailed planning for further improvements. The guiding principle was to immediately implement all feasible measures.
4. Various methods were considered for dredging the inverted siphon, including manual labor, machinery, and coastal sand-pumping techniques. However, to expedite the interconnection of the main lines on both sides of the Beigang River, it was required that all aspects of the project be promptly executed, except for the time-consuming pipeline dredging.
5. To swiftly carry out directives from higher authorities, the Yunlin Irrigation Association immediately began surveying, designing, and constructing the necessary infrastructure. The Irrigation Association was also authorized to directly hire laborers to execute the project when necessary.

The total project cost was estimated at NT$5 million

Along with submitting the construction plan, the Yunlin Irrigation Association analyzed the inverted siphon, which was originally designed with a maximum flow capacity of 4 cubic meters per second (CMS) and capable of irrigating 2,895 hectares. As the pipeline had been out of use for many years, its existing flow capacity was unknown. Therefore, the future irrigation area it could support would depend on its actual water conveyance capacity.

Analysis of Water Conveyance Volume and Irrigable Area:

1. With a flow rate of 4 CMS, the irrigable area is 2,895 hectares.
2. With a flow rate of 3.5 CMS, the irrigable area is 2,275 hectares.
3. With a flow rate of 3 CMS, the irrigable area is 1,950 hectares.
4. With a flow rate of 2.5 CMS, the irrigable area is 1,650 hectares.
5. With a flow rate of 2 CMS, the irrigable area is 1,300 hectares.
6. With a flow rate of 1.5 CMS, the irrigable area is 975 hectares.

To ensure timely support and address the drought needs of the Chianan region, the association immediately commenced surveying and design work, with the entire process scheduled to be completed within 50 working days.

Overview of the Inverted Siphon:

1. The inverted siphon is located at the terminus of the Zhuo Main Canal, managed by the Yunlin Irrigation Association, beneath the riverbed of the Beigang River, near the terminus of the North Main Canal, managed by the Chianan Irrigation Association.
2. The inverted siphon was constructed in 1930, with a length of 218 meters. In 1964, in coordination with the construction of the Lunziliao section of the Beigang River's Luliao embankment, the pipe was extended by 206 meters, bringing the total length, including the transition section, to 447 meters.
3. The inverted siphon’s northern section has a circular cross-section with a diameter of 1.8 meters and a length of 207 meters. The southern section has a rectangular cross-section, with a height of 2 meters, a width of 1.8 meters, and a length of 219 meters. The intake elevation for both sections is 11.5 meters above sea level, while the bottom elevation of the pipe is 5.7 meters, resulting in a vertical drop of 6.11 meters.
4. The planned flow capacity of the inverted siphon is 4 cubic meters per second. Between 1950 and 1962, water flowed through the pipe 36 times: 28 times diverting water from north to south and 8 times from south to north. The maximum flow recorded was 3.362 cubic meters per second, with a flow rate of 2 cubic meters per second noted in 1977.
5. Based on an estimated flow capacity of 4 CMS, the inverted siphon, operating under a rotational irrigation system, could irrigate 2,895 hectares of rice fields or 8,000 hectares of mixed crops.
6. The North-South Water Diversion Project was executed under the principles of abundant water availability and mutual benefit through shared water resources between Yunlin and Chiayi.

The project reached a temporary conclusion with the completion of construction and initial water flow tests. In the Dongshi irrigation area of the Chianan Irrigation Association, which had a planned irrigation area of 2,815 hectares, the actual water volume diverted through the inverted siphon to the North Main Canal was 3,169,272 tons, irrigating an actual area of 997.3 hectares.

Based on a review meeting held by the Taiwan Provincial Government’s Water Conservancy Bureau (the predecessor of the Water Conservancy Department and the Water Resources Agency) on April 6, 1992, it was unanimously recognized that the project increased the sweetness and yield of corn and sugarcane. It also benefited soil improvement, reduced water evaporation, and prevented wind erosion. The project has demonstrated positive effects on emergency water supply for irrigation and the efficient utilization of water resources.