In order to confirm the feasibility of the dam-building method, Yasuda studied the papers of world civil experts and referred to the dam-building methods of advanced countries. 1922, he went to the United States for field investigation, and finally decided to adopt the construction method of semi-water earth-rock dam and build the dam with his own innovative technology. This is the only wet dike reservoir in Asia and the only one in the world. The American Civil Engineering Society was named after "Bathien Dam" and introduced to the world in the journal of the Society. In addition, it is the first in Asia to introduce large steam-powered machinery for civil engineering, including shovels, pressure sprinklers and gravel transport vehicles. After 7 years, a diversion tunnel with a length of 3,078 meters was built, which runs through the five mountains and connects with Zeng Wenxi. Due to the large scale and difficult construction, the whole Wushantou dam and tunnel project died 134 people.
After ten years' efforts, the water conservancy facilities of Jian 'an Town, which was the first in Taiwan Province Province, the first in China and the first in Asia, were finally put into use on April 10 (5 years in Showa). The dam of Wushantou Reservoir is 1273 m long and 56 m high, with a full water area of 13 km2 and a storage capacity of10.50 billion tons. It was the largest reservoir in Asia at that time and the third largest reservoir in the world. The total length of irrigation channel is 10000 km, the drainage channel is 6000 km, the length of main revetment and dike is 228 km, and the Jianan Plain is irrigated150,000 hectares of farmland. With irrigation and thorough land improvement, the original three obstacles of flood, drought and salt damage in Jian 'an Plain have been completely removed. After the completion of the whole project, the agricultural output of Jianan Plain has greatly increased, benefiting 600,000 farmers. The annual output of rice, sugarcane and other crops reaches 83,000 tons. Because of its great contribution, Hatta Yoichi was honored as "the father of Jian 'an Nanda" and "the father of Wushantou Reservoir" by later generations. Technician An Tian has since established his position in Japanese civil engineering.
Because of the limited water intake and insufficient water supply, Zeng Wenxi developed and implemented the "three-year rotation water supply method" to maximize the irrigation area. He divided the land in the southern part of Jianan and Shenzhen into 50 hectares, and each small piece of land was planted with rice, sugarcane and miscellaneous grains in turn within three years. The operation method is as follows: setting sluice to control the water supply channel, and fully supplying water when planting rice; Sugarcane seeds are only watered during planting; Planting miscellaneous grains does not mention water supply, so the vast majority of farmers can enjoy the benefits of farmland water conservancy. And set up "Jian 'an Town Water Conservancy Corps" to manage sluice and water distribution operation, which is the predecessor of "Jian 'an Farmland Water Conservancy Association". Later generations have many views on the "three-year rotation water supply law", including that it can benefit more land and farmers, but it is also a land use system that is very beneficial to landlords, sugar factories, large enterprises and the government.
After the completion of Jian 'an University, Hatta Yoichi moved back to Taipei, worked as a technician in the Governor's Office of Taiwan Province Province, and served as the head of the water conservancy unit of the Civil Engineering Department, and began to work on the land improvement plan of Taiwan Province Province. He also organized the Technician Association as the president, established the Taiwan Province Water Conservancy Association, trained the younger generation of water conservancy technicians, and published many professional papers in Taiwan Province Water Conservancy. The "Civil Surveying Technician Training Center" was established in Taipei, and enrollment began, which is the predecessor of the current "National Ruifang Advanced Industrial Vocational School". Later, he participated in the investigation of Dajiaxi power generation plan, the formulation of irrigation plan in Fujian Province, the investigation of agriculture and forestry in Hainan Island, and the investigation of Manchukuo (Northeast) reservoir. From 65438 to 0939, Hatta Yoichi was promoted to be an official technician and became the highest professional technician in the Governor's Office.