It has taken decades for the world's largest water diversion programme to come about and Beijing has taken all necessary measures to ensure that each drop of water, transported over great distance, is safe.
As a key section of the South-to-North Water Diversion Project prepares to go into operation, water quality tests show the battle against pollution is being won.
The first phase of the central route of the South-to-North Water Diversion Project is scheduled to be launched in late October.
The water quality of 80 per cent of the 49 monitored cross sections met mandatory standards last year, proving the water flowing in the central route is clean and safe, said Yu Youjun, deputy director of the State Council's office of the diversion project commission.
"Through 10 years of pollution control, the goal of supplying clean water will be achieved when the central route commences next month," Yu said.
The water transfer project, which is the world's largest, aims to transfer almost 45 billion cubic meters of water every year from the Yangtze River in the south to help curb water shortages in the north, including Beijing.
This will be achieved via three water diversion routes－an eastern route that started to supply water in December, as well as central and western routes.
Next month, the central route will transfer 9.5 billion cubic meters of water every year through 1,277 kilometers of canals and pipes from the Danjiangkou Reservoir in Hubei province through Henan province to reach Hebei, Tianjin and Beijing in the north.
Unlike the eastern route that saw an upgrading of the Beijing-Hangzhou Grand Canal for a water diversion channel, the central route involves raising the height of the Danjiangkou Reservoir from 162 meters to 176.6 meters and building canals and pipes to divert water from the reservoir to North China.
The South-to-North Water Diversion project office has long been concerned about water contamination in areas along the central route from industry, domestic sewage and waste from urban and rural areas.
"Some rivers like the Jianhe and Guanshan (from Shiyan, Hubei province) flowing into the reservoir were polluted and even grayish-black in colour because of contamination," said Shi Chunxian, an environmental protection official at the diversion project office.
"After years of pollution control, the water quality has improved."
As the water of the central route is mostly transferred in tunnels and pipes, pollution prevention measures focus on reservoir protection as well as protection of the rivers flowing into it, Shi said.
In order to guarantee the water quality of the central route, authorities invested about 8 billion yuan (S$1.6 billion) to build 174 sewage treatment plants with a treatment capacity of 1.5 million metric tons per day. This was complemented by 98 waste plants processing 8,500 tons every day in the reservoir area, according to statistics from the diversion project office.
Another 2 billion yuan was invested to tackle pollution of rivers flowing into the Danjiangkou Reservoir, and more than 1,000 polluting companies, including paper plants and mines, were closed, the office said.
Zhao Yingmin, director of the pollution prevention department under the Ministry of Environmental Protection, said the pollution control measures were "effective", with only 5 per cent of the water flowing into the reservoir failing mandatory water quality standards.
From January to August, the water quality of the Danjiangkou Reservoir maintained standards above Grade II, according to the Ministry of Environmental Protection. Grade III is lower than Grade II and the minimum standard for drinking water after treatment.
"After going into operation in October, samples of water from seven cross sections will be tested to identify 24 items including dissolved oxygen, odour and colour," Zhao said.
By then, the project will provide about 30 per cent of Beijing's annual water consumption.
The capital also set up three 24-hour water quality monitoring centers in the Huinanzhuang pumping station, the Daning surge tank and Tuanchenghu lake to tackle emergency pollution incidents, said Qiu Wenshun, director of the water diversion centre under the Beijing office of the project.
"Once a water contamination incident occurs, we will shut off sluices to prevent polluted water entering the water supply system and use the Miyun Reservoir as a backup source," Qiu said.
In addition to Beijing, the new water supply will come as a huge relief to northern provinces and regions, which suffer from severe water scarcity caused, in part, by excessive groundwater pumping.
Research by the China Geological Survey showed the North China Plain is one of the most vulnerable areas facing land subsidence due to excessive groundwater pumping and economic development, with the surface level of Cangzhou, Hebei province, sinking 2.4 meters since the 1970s.
"Without the project, Beijing and Tianjin may face severe land subsidence due to years of excessive groundwater pumping, threatening city security," Yu said.
While easing the diminishing water table, he said, a 30-to 60-meter-wide green belt of grass and trees is being built along both sides of the central route.
As of the end of July, about 249 billion yuan, or 98 per cent of the project's total investment, has been spent, official statistics showed.
Conservation still a priority for capital
With the central route of the South-to-North Water Diversion Project about to bring 9.5 billion cubic meters of water each year to benefit Beijing and the dry north, authorities said conserving water and enhancing water efficiency are still a priority for the north.
He Fengci, deputy director of the Beijing office of the South-to-North Water Diversion Project, said that although Beijing will receive more than 1 billion cubic meters of diverted water every year, the capital's water scarcity cannot be alleviated long-term because of the surging water demand that comes with rapid economic development.
"Every drop of water is precious," He said, adding that no matter how much water can be diverted to the capital, saving water and raising water efficiency cannot be neglected.
The annual per capita water consumption in Beijing is about 100 cubic meters, equaling about 10 per cent of the international warning line for water shortage of 1,000 cubic meters, according to the office.
According to the Beijing Water Authority, water resources have reduced dramatically due to a continuous drought since 1999, decreasing the annual water flow into Miyun Reservoir to 270 million cubic meters on average over the past 13 years, about 72 per cent less than the average annual volume before 1999.
While water resources have declined in the capital, the population grew from 12.6 million in 1999 to 21.1 million in 2013, according to the Beijing Bureau of Statistics.
Li Yuanyuan, vice president of the Institute of Water Resources and Hydropower Planning, said rapid economic development and urbanization bring surging demand for water.
Domestic water consumption in Beijing increased steadily by 50 million cubic meters annually in recent years, according to the Beijing Water Authority.
He said conserving water is the solution for sustainable economic development and the water project can help meet the surge in water demand.
Zhang Xiaojian, a professor of environmental protection at Tsinghua University, said water from the central route will help the capital protect the environment and restore groundwater, which has been excessively pumped in past years.
He added that groundwater pumping will gradually be reduced by closing self-supply wells after full and steady operation of the central route.
More than 50 per cent of the water will be used for domestic and industrial use, covering water consumption over 6,000 square kilometers, according to the Beijing Office of the SNWD project.
Part of the diverted water will be stored in three reservoirs as strategic water resources for emergency, He said.
Although the water quality is guaranteed, surveys conducted by a laboratory in Danjiangkou Reservoir showed some residents in Beijing may notice that their tap water has become a little yellowish because the central route's water is different in terms of such as pH level, causing corrosion of old iron pipes.
Beijing Waterworks Group authorities said efforts have been made to improve the pipeline network to reduce such possibilities and emergency plans drawn up to deal with such incidents.
Workers share environmental ethic
Li Jinqun lost an arm in an industrial accident, but his daily routine has remained largely unchanged for years. At 7 am, he leaves his house in Taocha, a village in Xichuan county, Henan province, to help clean the Taocha canal, the starting point of the South-to-North Water Diversion Project's central route.
Li, 66, has witnessed the construction of the project over the past 44 years and said he is glad to see it finally reaching completion.
He joined the project back in 1970 and lost his right arm that May in a construction site accident. He was determined to make a contribution and insisted on working after he recovered.
"Even if my physical capacity is limited, it is important to maintain the environment and provide clean water to provinces that badly need it," Li said.
Laboratory researchers provide key long-term data for operators
Although he repeats routine inspections on water quality for hours each day, Zhang Lei said he never gets bored.
For him, the pioneering research could be an important statistical source to guarantee safety when water diverted from Danjiangkou Reservoir arrives in Beijing.
In May 2011, the Beijing Waterworks Group, a major water supplier in the capital, set up a laboratory near Danjiangkou Reservoir, the source area of the central route of the South-to-North Water Diversion Project, to collect data on water quality, variations in seasons and other records.
When the lab was launched, Zhang, then a postgraduate student of environmental engineering, started his research on the water quality in the reservoir with other students and professors from universities and institutes in Beijing and Tianjin. Both cities will benefit from the diverted water.
"The routine inspection is kind of tedious in some people's opinion, but I am proud to participate in the massive engineering of the South-to-North Water Diversion Project in this way," the 31-year-old researcher said.
Zhang and his colleagues have followed strict procedures on water quality inspections every day, collecting water samples from the simulation water plant, and conducting a series of experiments to get thorough analyses and indexes for the water. The experiments can take hours or even a whole day depending on the water situation.
"The daily records combined can be an important source for water processing in the future," Zhang said.
From their continuous records, the researchers have found that the water quality in the reservoir is relatively stable in accordance with seasonal changes. In terms of hardness, it is better than the underground water pumped in Beijing.
However, in the flood season, the water in the reservoir becomes muddy as more water coming from streams and rivers flows into it. The indexes involving organic matter increase, according to research based on more than two years' records.
"In response, the water processing methods should be changed to keep the drinking water quality at a high level," Zhang said.
The team has also conducted several tests to simulate various conditions, helping them and the water plant in Beijing become aware of changing situations and giving them the ability to plan ahead.
Such tests by Zhang and his colleagues have become the major reference in Beijing by which to process the diverted water.
The laboratory has also tested the current processing methods used in Beijing's water plants. Through simulation processing, it proved that the methods used in Beijing would also work for the water from Danjiangkou Reservoir, according to a report from Beijing Waterworks.
"Our laboratory and the research institutes in Beijing support each other to guarantee the safety of water diverted from the reservoir, more than 1,000 kilometers away," Zhang said.
Once the central route is in operation, delivering water to the north, the laboratory will remain open for Zhang and his fellow researchers to continue their experiments.