An image of a dried-up Yongding River (Source: Beijing Nangong Tourist Attractions).
Yongding River is the parent river, the main segment of a river system that is fed by smaller tributary rivers, of Beijing. For more than 3,000 years, the river provided drinking water to the locals and nourished their culture. It was once called Wuding (meaning unstable in Chinese) River, demonstrating its unpredictable flow change, and the Kangxi Emperor of Qing Dynasty later renamed it Yongding, expressing his “wish for peace” with the river forever. Even during the past half century, there were two serious bursts of the river, again demonstrating the river’s power and unpredictability.
Yet, the powerful Yongding River has been gradually losing its vitality since the 1980s. The Guangting reservoir, the largest reservoir on the Yongding River, has three hydropower stations and was designed with a storage capacity of 4.16 billion m3. The present water storage is only 164 million m3, however, meaning only 4 percent of the reservoir’s storage capacity is being used. The main cause of these low storage numbers is the numerous dams built upstream of the reservoir, which consume much of the river’s water before it can reach Guangting reservoir. At the same time, soil erosion and upstream pollution have also led to a decline in water quality, which used to meet drinking standards but only meets industrial and landscape standards today. The river also frequently dries up, and parts of its 3200 km2 drainage area within Beijing have turned into desert, causing severe dust storms.
In order to let Yongding River flow again, 130 million m3 of water is needed annually. With the launch of “Yongding River Green Corridor Construction Plan” (2010-2014) and the relocation of Shougang Group (finished by 2010), an iron and steel enterprise with the greatest levels of production in the country, the ecosystem might be restored as industrial water consumption has begun to decrease sharply. As Beijing suffers through extreme water shortages (the per capita water resource is less than 100 m3), it has needed to gather water from recycled water plants, urban runoff, upstream reservoirs, and the South-to-North Water Diversion Project for Yongding River. This marks the first time China has attempted to revive a river and restore an ecosystem at such a high cost (17 billion Yuan, a little more than 2.66 billion USD).
Yongding River is one of the many rivers in China that suffers from over-exploitation of hydropower. As China shifts towards more sustainable development, smarter hydropower development schemes should be adopted to prevent the repetition of Yongding River’s depressing story. There need to be impact assessments done that measure the effect the development of hydropower projects have on river bed and river bank ecology.
Large-scale projects are the most interesting projects to Chinese hydro developers because they can be ramped up rapidly and predictably, and can also provide extra services, such as flood control and irrigation. Most importantly for developers, the hydraulic turbine’s efficiency increases with size, making larger projects more attractive. Yet, the environmental impacts of the existing large-scale project are quite controversial, demonstrated by Three Gorges Dam, which has received a lot of criticism both domestically and internationally.
Small-scale hydropower used to be considered one of the most cost-effective energy technologies for rural electrification in China. This is important because, even by the end of 2010, there were still 5 million people in rural China without access to electricity. The technically exploitable capacity of small-scale hydropower in China is estimated to be 128 gigawatts (GW), with an present situation and future prospects of hydropower in China. With such great potential, in addition to policy incentives such as a consumption tax abatement, small-scale hydropower has been growing relatively fast, especially over the past decade. Small-scale hydropower is now widely distributed in more than 1,600 mountainous counties around the country. Western China, a very rural region of the country, accounts for present situation and future prospects of hydropower in China.
Theoretically, small-scale hydropower should have less environmental impact than large-scale hydropower, especially for small-scale systems that do not have dams. However, since the Chinese definition of small-scale hydropower stands officially at 25 MW, 15 MW greater than the most widely accepted figure worldwide, China’s small-scale hydropower development projects still have a tremendous impact on local environments. For instance, the rivers in the Shennongjia Scenic Area, which used to have some of the wildest scenery in the remote northwestern province of Hubei, dried up due to over-exploitation from too many small-scale hydropower stations. Worse still, this is not an isolated incident as there are many other cases of rivers drying up in China due to over-exploitation of small-scale hydropower plants.
Since there is tremendous biodiversity in many of the regions in China where there is high potential for small-scale hydro, research and impact assessments need to be done on a case-by-case basis to ensure minimum damage to local ecosystems. For example, during the construction of small-scale hydropower plants, innovative turbines and improved techniques to minimize interference with local fish populations should be considered.
After all, for both large-scale and small-scale hydropower projects, environmentally friendly energy generation is the goal as China is trying to shift, along with much of the world, to a more sustainable development path.