XINING -- China has vowed to protect the environment while it builds a 634-km road crossing in the most vulnerable parts of the Qinghai-Tibetan Plateau.

The road, which will link the counties of Gonghe and Yushu in Qinghai province, is the first to cross the Sanjiangyuan area -- the headwater region for the three major rivers in East Asia: Yellow River, Yangtze River, and Lancang River.

Work crews have been asked to preserve the meadow, which is being removed during construction and then replant it along the road after the road is built.

The ecology is vulnerable in Sanjiangyuan and once damaged the grassland is difficult to restore, said Song Fanghua, chief engineer for the construction under Qinghai Zhengping Road and Bridge Corporation.

The money spent on protecting the environment during the construction of the Gonghe-Yushu road has cost 300 million yuan ($47.2 million), about three percent of the total investment and an unprecedented figure in road building history in Qinghai, said Nachitse, deputy head of the Gonghe-Yushu road project.

"We aim for a 'seamless' construction, which means the construction leaves no marks on the environment," the official said.