More than 1,000 lakes have disappeared in China in the past half century, and more than 80 percent of lakes along the lower reach of the Yangtze River have been troubled by algae outbreaks, officials warned Monday at the beginning of the 13th World Lake Conference in central Hubei Province. (Xinhua Photo) Photo Gallery>>>

    BEIJING, Nov.3 -- More than 1,000 lakes have disappeared in China in the past half century, and more than 80 percent of lakes along the lower reach of the Yangtze River have been troubled by algae outbreaks, officials warned Monday at the beginning of the 13th World Lake Conference in central Hubei Province.

    With the theme of "rehabilitation of our lakes," the four-day gathering of more than 1,400 environmental experts and scholars from over 40 countries will focus on challenges facing the world's lakes.

    One of the key questions will be in regard to handling China's problem of polluted drinking water, which has actually gotten worse as a result of the country's rapid growth.

    "Deterioration of water quality in lakes hasn't been controlled yet … Water quality of some lakes has descended to class V (seriously polluted) or even worse, resulting in algal bloom and oxygen deficiency," Minister of Water Resources Chen Lei said at the opening ceremony of the conference.

    He pointed out that most of the lakes in southeast China are suffering from eutrophication, a state when the waters have a large influx of mineral and organic nutrients, resulting in excessive algae growth that suffocates other creatures in the water.

    "Among 43 lakes we investigated, 27 lakes have been eutrophicated, and 12 lakes, including Taihu Lake, Chaohu Lake and Dianchi Lake, are in a severe eutrophication state," he added.

    Taihu, located near Shanghai, is China's third-largest lake. Chaohu, in Anhui Province, is the fifth-largest.

    Disappearing bodies

    Under the dual effects of climate change and human activities, lakes are witnessing a continuous fall in water levels and decrease in fishable areas, experts said.

    "The number of lakes has been reduced by 1,000 in 50 years, and there are 20 lakes on average disappearing in China every year," Zhang Yongchun, an expert from the Nanjing Institute of Environmental Sciences, told the Global Times Monday.

    The country lost 9,570 square kilometers of water area, and 51.6 billion cubic meters of water-storage volume, in the past half century.

    There are more than 2,300 lakes larger than 1 square kilometer in China.

    Hubei, once known as "the province of a thousand lakes," now has only 2,440 square kilometers of lakes, or a third of the water area it had in the 1950s.

    The water level at Poyang Lake, a large freshwater body, is also shrinking rapidly.

    "It's a result of human activities, such as reclaiming the lake for farmland, over-drilling of water, and diverting river routes recklessly," Yu Hui, a professor from the Chinese Research Academy of Environmental Sciences, said in an interview with the Global Times at the conference.

    The deforestation around the upper reaches of the Yangtze River has brought large amounts of sand down into the lakes, which also reduces the water levels in the lakes.

    Breaking the eco-system

    Putting the current state of Dianchi Lake in layman's terms, one expert said it is "terrible indeed."

    As the sixth-largest freshwater lake in China, this "pearl of the highland" in southwestern Yunnan Province has been plagued by blue algae in recent years, with the sticky water coating shores like green oil paint.

    "In the past, it broke out seasonally, while now it blooms all through the year," the expert, Na Zhongyuan, head of the Institute for Ecological Agriculture of Yunnan Province, told the Global Times Monday.

    Instead of manually bringing water in from rivers to fill Dianchi, as is often done with other lakes, "we have changed our plan to internal water treatment, which means improving the ecosystem of the lake," Na said, stressing that it is a long-term solution, not a quick fix.

    Effortful treatment

    Taihu Lake, the source of drinking water for 4 million Wuxi residents, was hit by a large bloom of blue-green algae in 2007, contaminating the water supply to many households.

    But since 2007, the outbreak area and frequency of blue-green algae has been significantly reduced, according to government reports.

    "The number of outbreaks has been reduced from 51 in 2007 to 48 this year, and the area dropped from 8,562 square kilometers in 2008 to 4,848 this year," Lu Guihua, deputy director of water resources in Jiangsu Province, said Monday.

    However, Taihu still faces severe water pollution, including accumulated internal pollutants that are hard to eliminate quickly. One of the major pollutants came from crabs farming in fenced-off areas of the lake, Lu said.

    The government has invested 14.5 million yuan in a five-year cleanup program.

    Yu said it is not a matter of funding, but rather how to stop factories from discharging pollutants.

    (Source: Global Times)