Yangtze Basin lakes shrinking as climate change, development takes its toll
The Yangtze Conservation and Development Report 2011 (YCDR 2011) shows that lower water levels, rapid urbanization and large water infrastructure projects across the Yangtze Basin are impacting the overall health of many lakes along the 6,300km river, which supports the livelihoods of nearly one-third of China’s population.
“Lake ecosystems in the Yangtze River Basin are showing tell-tale signs of degradation, and problems like water eutrophication from industrial runoff are on the rise. We are also seeing a decline in flood retention capacity and insufficient water supply. These changes are putting increased pressure on many of the species found in the Yangtze, including the finless porpoise and Chinese carps,” says Yang Guishan, President of the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
Climate change in the Upper Yangtze
While water resources will increase over the short term, the YCDR 2011 predicts that the long-term impacts of climate change will result in massive water shortages in headwater regions.
“Over the short term, increased glacial melt in the Qinghai-Tibetan plateau means more water. But after the glaciers are gone – and with them the source of the Yangtze River - available water resources will decline. The lack of water could cause lakes that depend on glacial melt to shrink or dry up completely,” says Yang Guishan.
Pollution, population and land reclamation
From 1950-2010, the central and lower reaches of the Yangtze lost approximately two thirds of its lakes due to increased land reclamation for agriculture and industrial development. This has resulted in a water storage capacity loss roughly equivalent to 20 million Olympic-sized swimming pools – and means that smaller floods now have the potential to inflict much more damage.
Meanwhile, population growth and rapid economic development - particularly in the central and lower Yangtze - as well as excessive fish farming has resulted in more serious water pollution issues and increased instances of eutrophication, a process where excessive nutrients diminish water quality in lakes or other bodies of water.
Water quality monitoring data from 2007-2010 in the central and lower Yangtze shows that 77 per cent of the 77 lakes with an area of 10 km2 or more could not provide safe drinking water, while over 88 per cent were in various stages of eutrophication. Meanwhile, in 2009 alone, over 33 billion tonnes of sewage was discharged into the Yangtze River Basin, nearly a 22 per cent rise from 2003.
Similar to the diagnosis offered in the previous two editions of the YCDR, the 2011 update points out that more work still needs to be done to ensure the future health of the Yangtze River:
“The Yangtze Conservation and Development Report 2011 shows that a comprehensive action plan is an absolute necessity to ensure the future of this irreplaceable resource,” said Jim Grandoville, CEO of WWF China. “WWF will be working with partners and seek solutions towards the protection and sustainable usage of the lakes along the Yangtze.”
The report also emphasizes the importance of mitigating the accumulative impacts of large infrastructure projects such as the Three Gorges Dam and South to North Water Transfer Project on the Yangtze River, especially downstream.
Known as the “Yangtze health check”, this is the third edition of the Yangtze Conservation and Development Report. It is jointly developed by WWF, the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences and the National Development Bank.