Dam affects bridges, old and new
XI'AN: The on-going dam project on the Bahe River, which runs through Xi'an's eastern suburbs, is drawing heated discussion in the capital of Northwest China's Shaanxi Province.
The dam is intended to raise water levels and submerge the ruins of an ancient bridge, thus protecting the bridge built more than a 1,000 years ago from erosion and flood.
But since the dam poses potential threats to two railway bridges some 50 metres down the river, local railway authorities strongly object to the project.
The ancient bridge on the Bahe River, also called Baqiao Bridge, is considered an important icon of Xi'an's local culture and history. Ancient literature refers to the bridge on many important historical occasions. It is said that ancient people in Xi'an used to send off their friends at the bridge, plucking willow branches as fond souvenirs signifying farewell.
On October 1, 2004, a flood in the Bahe River flushed away the sand that covered ruins of the bridge built in the Sui Dynasty (AD 581-618), thus exposing the bridge to furthur erosion and deterioration.
The 11-pier and 80-metre-long ancient stone bridge is believed to be the oldest ancient bridge of its kind, according to local archaeologists.
"The bridge was discarded in the Yuan Dynasty (1271-1368). It was put under State protection some 20 years earlier than the famous Zhaozhou Bridge," said Yuan Zhongyi, archaeologist with the Shaanxi Provincial Archaeological Research Institute. The Zhaozhou Bridge, built in around AD 600 in the northern province of Hebei, is perhaps the oldest stone-arch bridge still in good shape - in the world.
Keep history or sacrifice it
ocal media, experts and the public have totally different opinions on whether to keep the bridge or sacrifice it for transportation needs, and there seems no way to please either side.
The railway bridges at the lower reaches are the main part of two railway lines: the Longhai Line and the Xi'an-Ankang railway. The Longhai Line connects Lanzhou, capital of Northwest China's Gansu Province, and Lianyungang, a coastal city in East China's Jiangsu Province, while Xi'an-Ankang railway runs through seven counties and cities in Shaanxi Province.
In 2002, a flood crashed the Longhai Line bridge and railway connection was suspended for nearly a month.
The damming project started in early March.
"The purpose of building the dam is to protect the ruins of the ancient bridge, because the raised water level will submerge the ruins, forming a kind of protection," said Wang Xuan, director of project management at the Xi'an Municipal Water Bureau.
The dam, 6.7 metres high and 360 metres long, with an investment of 20 million yuan (US$2.41 million), will be completed before the main flood season in late May, Wang said.
However, the Xi'an railway authority is strongly against the construction, and has sent letter to local government to ask for an immediate suspension of the project. It has also asked the Shaanxi Provincial Supervision Bureau of Safety Production for help, according to Zhang Yingping, deputy director of Anti-Flooding Office of the Xi'an Railway Bureau.
"The Railway Transportation Safety Regulations issued by the State Council on December 27, 2004, stipulate that units and individuals have no right to build anything withing a scope of 1,000 metres at upper or lower reaches from a railway bridge, and anything built in such areas should solicit the opinion of the railway authority before construction," Zhang said.
But Wang from the project management department said they did not ask for the opinion from the railway side because the time is limited, and the project must be completed before flood season.
Experts have different opinions on the construction of the dam.
Yan Baojie, a professor of Transportation School with Xi'an-based Chang'an University, expressed worries about whether the newly-built dam can stand the flood.
"If the dam breaks, a big volume of high-speed water would definitely cause more harm to the railway bridges 50 metres down the river. And the water may wash out the sand-and-stone base around the railway bridge piers, and then destroy the bridge," Yan said.
However, Zhao Fasuo, one of the dam project designers and director of the Geological Engineering Department of Chang'an University, said that the dam can bear the flood because it makes the river wider and reduces the flow speed. The original riverbed is only 100 metres wide while the 360-metre-wide dam will expand the river to 300 metres.
"It can disperse the water pressure, which used to be undertaken by only two or three piers, to other piers, thus protecting the railway bridge," Zhao said.
(China Daily 05/18/2005 page5)