The ecology of China's lakes and rivers has become unbalanced, according to a top environmental official.
Speaking on Monday at the Yangtze Forum to discuss flood control, water resources, and environmental issues, deputy water resources minister Hu Siyi said the issue of ecological balance has become an unavoidable and long-term task for water-resource policymakers.
Hu told delegates that water resources management in China faces "major challenges," with a huge increase in complexity since the middle of the last century.
Sichuan-based environmentalist Yang Xin, founder of the nongovernment group Green River, said the Yangtze River basin in particular is so threatened that special legislation is needed to protect it.
"The source regions of the river systems need to step up environmental protection," Yang said. "This means fewer grazing herds so as to minimize erosion, and to protect the source regions."
"In the middle and lower reaches of the rivers, there definitely needs to be a clampdown on pollution," Yang added. "It is possible to improve the water quality in the Yangtze River."
He said that the Yangtze might be China's longest river, but that it isn't inexhaustible.
"While the Yangtze is an abundant water resource, there should still be some attempts to save water," Yang added.
Hu said China is now swinging between the extremes of "too much" water during flood seasons, and "not enough" water, largely due to rapid economic growth.
He said that problems of water quality, erosion, and a deteriorating ecosystem are accelerating, with no fundamental changes taking place.
Jiang Shihua, a resident of the Yangtze city of Chongqing, said local residents have noticed an improvement in water quality since the building of the massive Three Gorges dam project.
But there are still many places that pump untreated waste water straight into the river, he said.
"There are some county-level small towns and private factories and enterprises which do expel polluted waste into the Yangtze," Jiang said.
Yang said the biggest crisis faced in the Yangtze region is the deforestation in upstream regions, leading to massive water run-off and a huge buildup of silt in the river.
The low-water season now begins earlier and earlier, and water quality is worsening to the point where drinking water supplies for major cities are under threat.
"In particular, in the middle and lower reaches of the Yangtze ... there should be tight controls on the heavy use of fertilizer in rural areas," Yang said.
"If they used a less concentrated form, then that would lessen the water pollution somewhat," he added.
More investment needed
Without further investment in improving water quality, the situation on the Yangtze is unlikely to improve, Yang said.
"China ... needs to step up its monitoring of waste water," he said, adding that local and central governments often invest in anti-pollution projects, but then do not provide money for them to continue.
"Usually, these things only work if the investment comes from the local government," Yang said. "But often in particularly polluted areas, they don't have enough money to get a guaranteed result."
He said that in the poorest, most heavily polluted areas, water treatment facilities exist, but often don't operate to specification, producing poor results.
Yang said the ecosystems of China's lakes and river should be built into a model for a greener GDP.
Hu also warned that the current craze for hydroelectric dam projects in China could leave river basins vulnerable to natural disasters, such as earthquakes.
China's reliance on hydropower stems from growing demand for energy and from government attempts to reduce greenhouse gas emissions.
Current estimates call for China to generate 310 gigawatts from hydropower by 2015, up from 208 gigawatts generated currently, a recent official report said.
"Major water projects currently under construction or in the pipeline in the country's southwestern regions are among the largest in the world," Hu told the Yangtze Forum.
He said such projects should include anti-earthquake technology.
Reported by Gao Shan for RFA's Mandarin service. Translated and written in English by Luisetta Mudie.