July 08th, 2012 | Global Times Plunging into the wetlands
Most people know them as bogs, marshes, swamps or fens, but wetlands like these can be vital parts of the ecosystem, helping to balance floods and droughts, cleaning and purifying water sources and being home to a vast variety of wildlife. Shanghai is built on an alluvial plain, and consequently is home to a lot of wetland areas. But as the city developed, pollution and commercial development have destroyed a lot of the native wetlands over the past 20 years. In 2008 city authorities worked with experts, businesses and universities to begin restoring the lost wetlands of Shanghai. There is good news.
In November 2008, the Qingpu district government and Shanghai City Appearance and Environmental Sanitation Administration launched the Dianshan Lake Wetland Restoration Pilot Project with organizations including Nanjing University, the World Wildlife Fund (WWF) and Procter & Gamble (P&G). The aim of the project was to make Dianshan Lake wetlands a healthy ecosystem and cleanse the water for Shanghai’s 23 million residents.
After three years of hard work, more than 600 hectares of wetlands have been restored helping clean up previously polluted ponds and rivers. The farms and fish ponds there, which have adopted eco-friendly technologies, have achieved almost zero emissions of pollutants. The quality of the water flowing through the wetlands has been improved from an inferior Class V to a good Class II or III. The planting of aquatic plants over large areas has helped remove an estimated 83 tons of suspended particulates, 2,300 kilograms of polluting nitrogen and 290 kilograms of phosphorus.
With the reconstruction of the wetlands and the surrounding rivers, lakes and ponds, more than 105 species of birds and 22 species of fish now flourish there, improving the area’s biodiversity. Farmers in the area have been planting rice and cress and raising fish and shrimp with organic food in lakes and ponds. They now make an average annual income of more than 50,000 yuan ($7,856), almost as much as they had earned from their non-environmentally friendly farming.
Zhuang Zhuang, the director of Green Oasis, a nongovernmental organization which also participated in the project, told the Global Times: “When farmers are inspired by this new eco-friendly technology which is benefiting their homeland, they become passionate and confident in it and want to continue the work so our wetland restoration can carry on.”
The wetlands around Dianshan Lake are the first being restored because they are found in the upper reaches of the Huangpu River, the main water source of drinking water for Shanghai. If the pilot project here is successful, it promises cleaner water for Shanghai and surrounding areas.
Shanghai’s forestry authorities explained that the broad area of wetlands between the city and Taihu Lake is important to Shanghai. It can function as a buffer zone to store water in the flood season and release water in droughts, helping adjust the volume of water in the Huangpu River. It also works to purify the water. According to the Shanghai Academy of Environmental Sciences, when sewage flows through the wetlands, pollutants and heavy metals like phosphorus can be absorbed by the plants, bacteria and the soil there. Research has shown that 1 hectare of wetlands can purify the irrigation water from 100 hectares of farmland.
But the source of the Huangpu River is completely open and lacks a natural barrier to protect it from pollution. Shanghai’s water source is at risk of being polluted by untreated water from Taihu Lake or by the chemical fertilizers from sewage in neighboring rivers in Qingpu district.
The Xiaofengyang wetlands restoration part of the Dianshan Lake Project has successfully conserved 130 hectares of wetlands since last year, working with WWF experts, Nanjing University and other groups.
Kang Hongli is the manager of the project and said that, initially, soil compaction was a very serious problem after years of using fertilizers and pesticides. To rectify the soil, scientists treated the earth with biological bacteria to help cleanse it and introduced other measures including special plants and natural fertilizers.
“We raise ducks on the rice farms and use their excrement to fertilize the rice plants,” Kang said. Without chemical fertilizers the rice farmers can reach 80 percent of their previous harvests and they are now experimenting with other technologies to improve on this.
As well as rice, wild rice stem and water mushrooms are being grown in the Xiaofengyang wetlands. These vegetables are easy to grow and can help bring in extra income for the local farmers. But as well this type of plant can absorb nutrients from the water and help purify it as they grow. After they are harvested the farmers return the unwanted parts of the plants to the soil, reusing them as organic fertilizer.
Some businesses have been invited to join this project to promote it publicly and help with finance. The companies now involved have spent 1 million yuan buying areas of polluted wetlands then paying local farmers 1,100 yuan a year per hectare to cultivate the land in an eco-friendly way.
It has taken some time for Shanghai to understand the importance of wetlands. It was only four years ago that city authorities actually calculated the amount of wetlands in Shanghai.
According to Shanghai’s forestry authorities, Shanghai has 319,000 hectares of wetlands divided into three sorts, lake or lacustrine wetlands, river or riverine wetlands and offshore or palustrine wetlands.
Of these the lake wetlands are the most seriously polluted and diminished. This is because almost all the areas surrounding the lakes have been occupied by commercial fish ponds and farms and artificial fertilizers have been allowed to flow into the lakes unrestricted.
The other varieties of wetlands have also suffered. Because it is situated in the basin and estuary of the Yangtze River, Shanghai has had less access to the fresh water from these sources as the runoff has shrunk and the erosion in the upper reaches increased. There has been little opportunity for the offshore and river wetlands to grow and refresh polluted soil. As well as water pollution, human activities and the arrival of external organisms have greatly affected the wetlands.
The Chongming Dongtan Birds National Nature Reserve is a well-established national project designed to encourage wetlands restoration. Here there are 1,100 hectares of wetlands where the quantity and quality of the water flow can be adjusted.
The reserve is home to fish ponds, flowers, plant life and the natural ecosystem is protected with pumping stations, special dam structures and drainage systems.
It is working for the birds – last year a survey showed that 38 species of birds visited the reserve 13,732 times. It has become an important nesting and breeding place for summer migratory birds and a home for winter migratory birds like waders, geese, ducks and herons.
Green Oasis has established a model wetlands project next to the Shanghai Science and Technology Museum.
Zhuang Zhuang, the director of Green Oasis, told the Global Times: “This area was just polluted silt and we treated it the way we have been treating the wetlands on Dianshan Lake. Now you can see it thriving like any protected land with clean water flowing and wildlife blooming.”
The model attracts more than 200 visitors every day – usually parents and children – who come to learn about wetlands, and how they function, lessons that are very important and need to be spread further.
“Not only ordinary people, but also our management and legislative departments, lack any real understanding of the importance of wetlands,” observed one anonymous forestry official in Shanghai.
According to Shanghai’s forestry authorities, there are regulations on the management of wetlands and these can be found in local regulations covering the management and supervision of wildlife and Shanghai’s environmental protection laws.
But these laws lack specific details on the management and protection of wetlands. Some regulations on the books stress the use of the wetlands for commercial purposes and do not mention protection at all. The regulations do not actually define wetlands, or describe the range of lands involved and critics say that they are inadequate to properly protect the wetlands.
There is also a problem with the responsibilities of the different government departments involved. The department of forestry is assigned to protect and manage the wetlands, but the departments that supervise oceans, agriculture and ports are also involved in matters related to wetlands.
The city’s forestry authorities plan to strengthen its ecological compensation methods and will apply for more national-level wetland reserves in the next phase, increasing their importance in local government programs.
The details are unavailable at present because a second government inquiry into Shanghai’s wetlands is still being carried out. It will be completed this year.
By Shen Shushu