SHANGHAI, a coastal city plagued by a shortage of quality freshwater due to water contamination on the rivers that weave through it, is forging ahead with efficient water use to instill a water conservation mentality in all sectors, and working to become a water-saving society this year.
Inside the Shanghai World Expo site, an artificial wetland has taken water from the Huangpu River and turned its water at class five into grade III, a potable level if treated, through biotechnologies with grasses and reeds planted inside its water intake ditches as a natural way to purify the water.
“After being purified through 1.8 km-long ditches, water supplied through the man-made swamp is now being used for the expo site’s waterscapes, saving 100,000 tons of tap water a year,” said Ye Dafa and Meng Ke, experts from an architectural design and research company in charge of the system.
Along the 1,045-meter-long Expo Boulevard, part of the main entrance to the Expo site, six horn-shaped structures known as “Sunny Valley,” have been built to gather rainwater for irrigating plants and cleaning toilets.
While shielding visitors from excessive sunshine, the horns can collect rainwater, particularly cloudbursts brought by typhoons from the coastal areas, by letting them flow into a water pool measuring 7,000 cubic meters through underground ditches for use around the boulevard.
In this way, about 50,000 cubic meters of water consumption could be saved a year, they said.
The horn-shaped structures can also help bring down the temperature for visitors passing through the boulevard on hot summer days by using the stored water in the ditches to make water sprays along with natural winds.
As one of the world’s largest metropolises, Shanghai seems to be brimming with water as it is surrounded by a number of rivers of the delta plain, downstream from the water-rich Yangtze River and Taihu Lake.
However, the city has long been short of a quality water supply due to water contamination around its river systems inland, said Liu Jun, an official with the Shanghai Water Supply Administration (SWSA).
To quench the water thirst for its long-term development, authorities have pushed forward efficient water use for millions of residents, industrial sectors, institutions including universities as well as farming with water-saving technologies and tips introduced for them to turn the city into one of China’s truly water-conscious cities, she said.
In the Shanghai Sunqiao Modern Agricultural Development Zone, which covers an area of 6 square kilometers in the Pudong area, computer-based drip irrigation systems using rainwater collected atop its buildings and stored at large rainwater pools are watering each root of growing vegetables straight through a needle-shaped pipeline.
“After filtering acid and alkali, the rainwater is contained to prevent secondary pollution to soil, and we water each vegetable 8 to 10 times per day with only 900 to 1,500 milliliters of the rainwater consumed each time,” said Yao Yongkang, a manager of the zone.
Ever since, authorities have nailed down a plan that will run until 2020 to use every precious drop of water to quench the coastal metropolis’ thirst and make a water-saving society to take shape by 2010 for its sustainability.
According to the latest statistics unveiled by SWSA, up to 3,805 water-saving measures have been carried out throughout the city during 2003-09 through updating urban water supply pipeline networks, popularizing water-saving home appliances, particularly, flush toilets for old residential districts, using treated water for urban waterscapes and service sectors like car washing.
By 2009, the maximum quantity of water the city has saved per day has amounted to 471,700 cubic meters.
