Xi'an (CNS) -- The protection office of the Xi'an Dayan Tower told CNS Wednesday that the 1-meter-leaning tower is being restored by 1mm every year, thanks to the rising underground water levels and effective protective measures.
It is estimated that the tower will return to a straight position in roughly 1,000 years.
Located in Ci'en Temple in southern Xi'an, the tower was built in 652AD to store classics for Xuanzang, a renowned Buddhist master.
The earliest record of its tilt was 198mm in 1719 during the Qing Dynasty. In 1998, the tilt was much larger, at 1.0105 meters facing the northwest.
In the experience of official Liu Zhong, almost 90% of all towers tend to lean. The leaning of Dayan Tower was caused by multiple reasons, one of the main reasons being excess extraction of underground water.
A long period of underground water extraction has sharply lowered the water level to below 100 meters. In order to avoid surface subsidence, the Xi'an government sealed over 500 wells surrounding the tower and refilled the underground water. Since 2000, the water level has increased and stayed normal.
For now, the tilt of the Dayan Tower decreased to about 900mm, and has been restored by roughly 1mm per year since 1997.
A systematic protection measures were taken to revitalize the surroundings, repave the water pipes, and improve on the impermeable base and roof, as well as the drainage works.
Moreover, two detective wells were dug on the north and south ground of the tower for water level figures. Another six monitoring spots were set up around the tower.
Liu did not take the thousand year calculation seriously though. In his view, the Dayan Tower has been kept in good conditions. The main job is to carry on with the present situation, more than making unscientific time guesses.
