An undersea pipeline started delivering fresh water from Fujian province on the Chinese mainland to an islet in Taiwan on Sunday to ease its water shortage.

The source of the water is Longhu Reservoir, the province's second-largest reservoir. The water will flow through an undersea pipeline to Weitou, a village on the islet of Kinmen.

The 388 million yuan ($57 million) project can now provide 34,000 cubic meters of fresh water, but local authorities said the capacity can soon be expanded to 55,000 cubic meters. The water costs NT$9.86, about 2 yuan, per cubic meter.

The pipeline from Jinjiang to Kinmen is about 28 kilometers long, 16 km of which is underwater at a maximum depth of 24 meters.

Kinmen, just 2 km from the island of Xiamen, has a chronic freshwater shortage, the per capita annual supply being only 167.9 cubic meters.

Local reservoirs struggle to meet demand, especially now as tourism on the islet increases. The shortage has also hampered production at the well-known local Kinmen Kaoliang Liquor plant.

At the request of the Kinmen county government, authorities on both sides of the Straits began negotiating the project in 1995. A contract was signed in 2015 and construction began the same year. It was completed at the end of last year and passed testing in May.

Huang Ju-hsin, deputy head of the county's construction bureau, said Kinmen used to draw 15,000 metric tons of groundwater daily, and the land is getting salty from the long-term pumping.

"Seawater desalination is also one of our options, but it's costly. The approximately 50,000 tons of water from the mainland will largely ease our water shortage," he said.

Yang Ying-hsiung, director of the China Kinmen Industry Development Association, said residents were looking for a stable water supply for years. "Such a livelihood project is a real need for us, and will bring more exchanges between the two sides. I also hope there will be cooperation in other fields, such as electricity or gas supplies from the mainland," he said.

Taiwan authorities wanted to postpone the project's opening ceremony, saying current cross-Straits relations were not suitable for it, but the water delivery could begin, the island's media reported.

Liu Jieyi, head of the Taiwan Affairs Office of the State Council, said at the opening ceremony on Sunday, that the mainland sincerely cares for the well-being of compatriots in Taiwan and works hard to bring benefits to them.

"There are always some people who don't want to see the well-being of Kinmen residents and the cooperation of the two sides. But such noise will never hinder the progress of cross-Straits relations," he said.