QINGDAO (XINHUA) - A drainage system dating back to the Qin and Han dynasties was discovered at the Langyatai ruins in the city of Qingdao, east China's Shandong Province.

Excavation started on two sites at the Langyatai ruins in October this year.

So far, an earth platform foundation, a drainage system, and a building base, which are on a grand scale and boast rigorous architectural crafts, have been discovered.

At one excavation site, three rows of pottery pipelines were found arranged in an orderly way. The pipes and their walls are thick, and the parts at the two ends of the pipes are similar to the ones of modern underground drainage pipe parts.

Each pipe is about 12m long and has more than 20 sections, and each section is about 60cm in length and 45cm in diameter.

"It is common for ancient buildings to have a single row of drainage pipes, and there are not many of them in two rows. The three rows at Langyatai are very rare," said Mr Peng Yu, head of the excavation team.

At the other site, not far away, a stone-made floor drain, dating back to the Qin (221-206 BC) and Han (206 BC-220 AD) dynasties, was also discovered. The drain was made with six stones of different sizes and the stone in the middle had a square hole.

Brick-made floor drains from around the same period were found at other sites around the country too, but stone-made ones are rare, Mr Peng said, adding that the stone-made one at Langyatai could be an indoor floor grain judging from its shape and precise details.

As recorded in documents, Langyatai was once where the emperors of the Qin and Han dynasties made inspection tours. Excavation shows that it is possible that there was once a royal building there which was directly related to the activities of the emperors.