Construction of the Shiya tunnel, the largest water diversion project of Dujiangyan Dam, the world's oldest water conservation project, started on 26th January, 2002 in Zhongjiang County of Sichuan Province in southwest China. The project will take three years to complete at a cost of 140 million yuan. The 6.1 km-long tunnel is the longest and the most difficult project at Dujiangyan Dam. The 2,257 year-old Dujiangyan irrigation project is the world's oldest irrigation project in function. It still irrigates some 666,000 hectares of farmland. Dujiangyan has been listed on the World Heritage List of UNESCO. 06/02.
