October 21, 2006
Three Gorges dam site, Hubei: China is struggling to find a solution on how to treat the huge amount of floating debris which is clogging up the Three Gorges Reservoir.
Cao Guangjing, deputy general manager of the China Yangtze River Three Gorges Project Development Corporation, said, “We are trying to find an efficient method to develop and use this floating flotsam, but so far we have made little progress.”
According to Zhang Weige, director of the department responsible for monitoring debris in the reservoir, about 1,000 tons of floating debris had been collected since Sept. 20 when the water level began to rise to 156 meters from 135 meters.
The floating debris consists of plant roots, straw, rotten leaves, branches and both household and industrial refuse. Currently, most of it is being salvaged and dumped on land higher than 175 meters – the final height of the dam – where it is either burned or buried. But this is not a viable long-term solution.
“The floating debris doesn’t contain much flammable content, nor is it economical to use them to generate electricity, ” said Feng Zhengpeng, director of the administrative department with the China Yangtze River Three Gorges Project Development Corporation.
“Also, the land will sustain permanent damage if the flotsam is buried,” said Feng. “There seems to be no good way of handling this situation.”
China has built or plans to build about 200 trash disposal grounds in the Three Gorges Reservoir area, in addition to three holes created in the dam for discharging debris.
About 200,000 cubic meters of floating debris flow into the mainstream of the Yangtze during a normal year.
“However, the flow of water has slowed down since the Three Gorges Dam was built,” said Feng.
“The debris has affected shipping and power generation,” said Feng, “and the problem has grown even worse since 2003 when the water level of the Three Gorges reservoir began to rise.”
The dam’s developers have entrusted local authorities along the reservoir in Chongqing Municipality and Hubei Province to clean upthe mainstream of the Yangtze and the upstream tributaries. It has also allocated an annual sum of 7.5 million yuan (about 937,500 U.S. dollars) to the Three Gorges Bureau of the Yangtze River Hydrological Bureau for monitoring flotsam cleanup results.
The developer has also spent 30 million yuan on a ship specifically designed to collect debris, with a capacity of 300 cubic meters. The ship will soon be put into service.
About 1.16 million people have been relocated since construction of the Three Gorges Project began in 1993. The project consists of a dam which is 2,309 meters wide and 185 meters high, twenty-six 700,000-kw power generators that will line the two banks of the river, as well as a five-tier and dual-track ship lock.
When completed in 2009, the reservoir of the 203.9 billion yuan project (25.5 billion U.S. dollars) will have a capacity of 39.3 billion cubic meters and 84.7 billion kwh of electricity will be produced annually.
Workers have completed the dam, the 14 generating units on the northern bank and most of the ship lock system, which is in service. Construction of the 12 generating units on the southern bank of the river is underway.
Categories: Three Gorges Probe