(Ecns.cn)！Zhouqu, once known as the "Shangri La" of northwestern China's Gansu Province, has suffered more than ten major landslides since 1823, but experts say the risk was greatly intensified by the felling of more than 126,000 hectares of forest between 1952 and 1990.
"The hills have become highly unstable and easily subject to natural disasters like landslides and mudslides," according to a 2006 report by Lanzhou University. "The situation is the result of deforestation, exploitative mining activities, construction of hydroelectric power plants and other development activities."
Nevertheless, a deadly mudslide in Zhouqu last August which left more than 1,000 dead and about 2,500 injured did little to slow the pace of environmentally-hazardous development there.
Despite strong opposition from experts, the local government was soon back to full strength in developing its hydropower industry. Among 68 hydropower station projects, which would bring the local government 20 million yuan in revenue a year, only one passed a security assessment and registered at the Earthquake Administration, according to a CCTV report.
A greedy industry was flirting with disaster, geological experts warned.
Massive ecological damage
Following the devastating mudslide, reporters noted that the hillsides above the Sanyan Valley, one of the worst-hit areas, had been completely stripped of trees, and even brush was sparse.
Zhang Jiacheng is an elderly villager living at Zhouqu. He recalled that disasters started visiting more often after a large area of trees was cut down in the 1980s.
In Zhang's view, the construction of hydropower stations is a killer of forests. They can not be built with trees standing on the mountain, he told CCTV, because they get in the way.
Bailong River, the largest tributary of the Jialing River, is 600 kilometers long, 450 kilometers of which flows within the borders of Gansu Province, including Zhouqu. The rapid flow of the river as it passes through the mountains makes it an ideal area for hydropower facilities. In addition to the 68 hydropower stations in Zhouqu, there are more than 1,000 hydroelectric power plants standing on the river, most of which are designed for small capacity.
River water is blocked by dams upstream and poured into the generating sets downstream through artificial channels, explained the Zhouqu Water Authority.
Even though newly planted trees are always damaged by the dams, villagers continue planting them, Zhang said, but they often don't survive due to lack of water. Wang Hao, from the Chinese Academy of Engineering, attributed this to soil erosion. The soil is very thin at the Bailong River valley, Wang explained. Once the original vegetation protecting the soil was removed, the soil flushed out easily. Hills were left barren and unable to absorb rainfall, so it became difficult to plant trees again, Wang told CCTV.
In addition, the clear river water of the Bailong becomes muddy with sediment after entering Gansu Province. There are no fish swimming in it; most have died out because their channels of breeding and migration were blocked by the dams, according to a local elder.
Experts warn that the widespread construction of hydropower dams has contributed to the area's vulnerability. Geologist Xu Daoyi worries about the situation. He told CCTV that the large number of hydropower stations had broken the stability of the hills near the river banks.
