Beijing, Nov 3 (IANS) 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 affected by algae outbreaks, officials said at the 13th World Lake Conference.
More than 1,400 environmental experts and scholars from over 40 countries are attending the four-day conference that began Monday in central Hubei province.

The theme of the conference is “rehabilitation of our lakes”.

“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 sq km of water area, and 51.6 billion cubic meters of water-storage volume, in the past half century.

“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 algae bloom and oxygen deficiency,” Water Resources Minister 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.

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.

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

Hubei, once known as “the province of a thousand lakes”, now has only 2,440 sq km 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.

The government has invested 14.5 million yuan (about $2 million) in a five-year cleanup programme. Yu said it is not a matter of funding, but rather how to stop factories from discharging pollutants.