ZHENGZHOU -- A ground-breaking ceremony was held on Sunday as construction began on a pair of tunnels -- part of the massive south-to-north water diversion project -- that will traverse the Yellow River and bring Yangtze River water all the way to Beijing.

The two tunnels will be 4,250 meters long and have a diameter of seven meters. They will pass underneath the Yellow River to the west of Zhengzhou, the provincial capital of Henan Province, according to builders.

One of the two tunnels is scheduled to be finished in March 2009.

In 2002, the Chinese government approved the south-to-north water diversion project which aims to relieve severe water shortages in parched northern areas.

The project will divert water from the Yangtze River, China's longest river, to the thirsty north of the country. Three routes are planned -- eastern, middle and western.

Construction has already begun on the eastern and middle routes, with a total investment of 200 billion yuan (US$26 billion).

The more expensive middle route carrying water from the Yangtze to Beijing will cost 137 billion yuan (about US$18 billion).

Its eastern route will divert water from the lower reaches of the Yellow River to north China's Tianjin Municipality.

The western route, still on the drawing boards, is expected to divert water from the upper reaches of the Yangtze to thirsty northwestern areas.