TIANMEN, Hubei, Feb. 26 (Xinhua) -- Work began here Thursday on a new, multi-purpose dam on the Hanjiang River, a tributary of the Yangtze River, China's longest waterway.

    The Xinglong Dam is one of the three main projects in the central route of a massive south-to-north diversion plan to bring water from the Yangtze River to the parched northern regions of China.

    Zhang Jiyao, chief of the Office for the South-to-North Water Diversion Project of the State Council, China's Cabinet), announced the start of work at a launch ceremony Thursday morning in Duobao Township, Tianmen City, in central China's Hubei Province.

    Zhang said the dam will cost 3.05 billion yuan (about 448 million U.S. dollars).

    Xinglong Dam is designed mainly to improve irrigation over farmland on both banks of the Hanjiang River and shipping when the river is in dry season. It also has power generation and flood control functions. A total of 1,240 residents in Hubei Province will have to be moved to make way for the dam.

    The dam will have spillways, infrastructure for navigation, turbo generators houses, lanes for fish passage through the dam, and linking bridges, according to the construction plan.

    Wu Kegang, director of Hubei Provincial Administration for South-to-North Water Diversion Project, said Thursday that workers had started construction on three fronts: anti-leakage walls, a man-made canal and one linking bridge section.

    "Hopefully, Hanjiang river could be stopped from natural flow in November this year," said Wu.

    The South-to-North Water Diversion Project, consisting of eastern, central and western routes, is designed to divert water from the water-rich south of the country, mainly the Yangtze, the country's longest river, to arid northern part.

    The eastern and central routes are already under construction. The western route, meant to replenish the Yellow River with water from the upper reaches of the Yangtze through tunnels in the high mountains of western China, is still at the planning stage.

    The central route requires construction of an open-cut canal through which water will be drawn from Danjiangkou Reservoir on Hanjiang River before being moved to Beijing and Tianjin.

    It will inundate 41 rural townships and 16 urban towns in Hubeiand Henan provinces, and 329,000 people will be forced to migrate.

    This route is scheduled for completion in 2013, and operation in 2014. It would be able to divert 9.5 billion cubic meters of water on average a year and would benefit more than 30 million people.

    Completion of this central route will improve the flood-combating capabilities of the middle and lower reaches of the Hanjiang River, said Li Hongzhong, governor of Hubei, Thursday.

    The three main projects in the central route are: raising of the existing Danjiangkou reservoir dam from 162 meters to 176.6 meters, construction of a 1,432-kilometer-long canal, and harnessing of the middle and lower reaches of the Hanjiang River.

    The third project on the central route includes Xinglong Dam and is designed to reduce the potential negative impact water diversion at Danjiangkou reservoir could cause on the middle and lower reaches of the Hanjiang River.

    Hanjiang River, with a length of 1,532 kilometers, is the largest tributary of the Yangtze. It originates in Micang Mountain in northwest China's Shaanxi Province and flows southeastward to join the Yangtze at Wuhan, capital of Hubei.