More than 50 percent of China’s rivers with catchment areas of at least 100 square kilometers have been lost, according to the country’s first-ever national water census.
The survey, conducted by some 800,000 surveyors and released on March 26 by the Ministry of Water Resources and the National Bureau of Statistics, found that there are currently 22,909 rivers in the country with catchment areas of 100 square kilometers or more.
The government’s previous estimate for rivers of that size, which dates back 60 years, was more than 50,000.
Huang He, deputy director of the group in charge of the census, said the discrepancy is mostly the result of inaccurate estimates, as well as the effects of climate change and water and soil loss.
When the previous estimates were calculated in the 1950s, technology was limited and the topographical maps used were incomplete, he said.
The surveyors found other old estimates that were also inaccurate, but in a more favorable way.
“For example, we used to think China had 8,700 water reservoirs, but the census shows the number has now reached 98,002,” South China Morning Post quoted him as saying.
However, many of these reservoirs are so small that the government has limited ability to regulate and control their water resources, it warned.
The survey categorized all of China’s waterways, reservoirs and irrigation zones, as well as the country’s water consumption, water and soil conservation, and infrastructure projects implemented to combat the effects of natural disasters.
There is still much to do regarding flood prevention measures, particularly for medium and small rivers, according to the water census report.
“Of all the river sections that require construction for flood prevention, 33 percent have been undergoing work, while only 17 percent are qualified for use,” it said.
Floods are a serious concern in China, because more than 90 percent of its cities and 66 percent of the population reside in possible flood zones.
The census also looked at groundwater use, finding that 400 cities that get drinking water from underground sources are overexploiting them, while 60 cities are “severely overexploiting” their groundwater.
"Overexploitation of water resources and pollution are the two major problems. With demand from the industry and urban consumption increasing, the water supply is already being severely challenged, especially in North China," Ma Jun, director of the Institute of Public and Environmental Affairs, was quoted by the Global Times as saying.
Ma urged a shift in the national water strategy, away from increasing supply and towards conservation and more efficient use.
In all, the survey categorized a total of 45,203 rivers of at least 50 square kilometers, 2,865 lakes with a regular surface area of over 1 square kilometers, and 98,002 reservoirs with 932.31 billion cubic meters in storage.
There are 46,758 hydropower plants with a total installed capacity of 333 million kilowatts in China, and irrigated land totals 66.8 million hectares, it found.
The survey has added to citizens’ fears that China’s economic development will lead to catastrophic environmental problems. Reports of air, water and soil pollution are occurring on an almost daily basis.