BEIJING, Jan. 15 -- A tunnel carrying some of the water diverted from the Yangtze River in the south to slake Beijing's perennial thirst in the north will soon be completed.

The 44.7 km culvert will supply water to residents in eastern and southeastern Beijing, said an official of the Beijing south-to-north water diversion office. Trials will begin at the end of January.

The project is vital to Beijing 's water diversion program and cost 9.2 billion yuan (1.5 billion U.S. dollars). The conduit passes under four railway lines, nine subway lines, 25 roads, 18 rivers and more than 600 underground pipelines.

Water from the Hanjiang River, the largest tributary of the Yangtze, began flowing into Beijing in late December after a journey of over 1,200 kilometers along the south-to-north water diversion project. Beijing has already received over 20 million cubic meters of water through the project.