THREE beckoning Shanghai wetland parks - one on Expo's waterfront doorstep - demonstrate new green technologies and ideas for urban living.

Two are reclaimed industrial brownfields transformed into "green lungs" that purify air, water and the frazzled urban spirit. One is the restoration of an endangered wetland.

All three are stunning World Expo success stories representing the turnaround of destructive urbanization.

All are easily accessible and have educational facilities.

They are award-winning Houtan Park right on the edge of the Expo site along the Huangpu River waterfront; Dongtan Wetland Park on Chongming Island, a natural wetland easily reached by highway bridge; and Paotaiwan Wetland Park in Baoshan District where the Huangpu and Yangtze rivers converge.

Houtan and Paotaiwan parks are reclaimed from polluted ship building and steel industry sites in a major environmental cleanup - just part of the city's efforts to go permanently green for the Expo and beyond.

Dongtan also generates electricity with bird-friendly slow-moving turbine blades.

Houtan Park

Houtan Park is a brilliant exposition of urban reclamation along the Huangpu River in the heart of the city. Birds soar and nest in the man-made, recreated wetlands and skyscrapers tower in the distance.

The 14-hectare park lies in the southwest part of Zone C in the Pudong New Area, stretching in a narrow band 2 kilometers along the Huangpu River. The polluted area was used as a steel factory, wharf and shipyard. A few buildings have been retained and incorporated into the educational design.

The award-winning ecological park was designed by Harvard-educated Professor Yu Kongjian from the urban planning department of Peking University. It opened in April after almost three years of work on the environmentally degraded site.

It can accommodate Expo visitors who wend their way through the tall high grasses. It also demonstrates green technologies and pollutant filtering systems. Every day its layers of soil, rock, sand and terraces produce 2,400 cubic meters of non-potable river water for use around the Expo site. Each day it saves US$500,000 in treatment of polluted water.

The scenic area features wild grasses, native plants, trees and crops, many of them blooming. There are green terraces, waterways, a 2-meter-high waterfall, winding paths and appealing views of the skyline.

The project statement says: "Houtan Park is a regenerative living landscape on Shanghai's Huangpu River riverfront. The constructed wetland, ecological flood control, reclaimed industrial structures and materials, and urban agriculture are integral components of an overall restorative design strategy to treat polluted river water and recover the degraded waterfront in an aesthetically pleasing way."

Aspects of Shanghai's industrial past remain. A shipyard wall has become a hanging garden of trailing plants. Nearby is a cafe and visitors can savor the scenery and enjoy performances.

A floating garden wharf replaces an old wharf and is covered with plants and flowers.

Dongtan Wetland

The Dongtan Wetland Park on Chongming Island is a 24-kilometer stretch of reclaimed wetlands adjacent to the Dongtan Bird Reserve, a one-hour drive from downtown Shanghai.

The reclamation has been so successful that six endangered Yangtze River alligators now live there. Birdwatchers have always loved it; it is an important stopover for migratory birds, such as white storks, tundra swans, hooded cranes and black-faced spoonbills. More than 150 species of birds live there.

The work began in 2003 and it has gradually been unveiled, most recently last month. It's still an ongoing work of wildlife conservation in the greenbelt near the eco-town on Chongming Island.

Nine years ago the natural wetlands were an environmentally damaged patchwork of farms, clogged ditches, dumping grounds and a big polluted pond.

But it has been cleaned up, crisscrossed waterways have been created, the pond is pure, and the entire area has been replanted and restocked with marine animals that are prey for birds. Aquatic plants help purify the water now.

If the degradation had gone unchecked, it is estimated that the damage would have spread to the bird reserve as well.

Facilities include a jetty, a bird-watching sanctuary and an earthquake and weather observatory.

As they enter, visitors see 12 large wind turbines used for energy generation and research. Because of its location and constant sea breezes, Dongtan is ideal for developing wind energy.

Nature lovers concerned about birds getting injured by turbine blades need not worry. These machines were built far from major nesting bird populations and the speeds are slow so that nearby birds will not be injured. They are also silent so the ecological environment is tranquil.

At the eastern end of Dongtan Wetland Park is a house with spectacular views of the East China Sea. It is expected to become very popular with visitors, especially photographers.

The Lu Haigang Seaview House is entirely made of wood and has a cafe on the second floor where visitors can watch the waving reeds, the sea and marshes.

The drinking water in Lu Haigang comes from 230 meters underground, and waters that people drink today have been beneath the earth for millions of years.

Paotaiwan Wetland

Just an hour's drive from downtown lies the stunning result of a herculean environmental cleanup, planting and wetland rescue.

Paotaiwan Wetland Park covers 53 hectares in Baoshan District, home to Baosteel, China's biggest steel maker. It is part of a comprehensive industrial cleanup that relocated numerous polluting enterprises since 2000.

The park represents a breathtaking reclamation of polluted industrial land along the Huangpu River where it meets the Yangtze River. It has a 2-kilometer-long waterfront, with clean beaches and marshes that have been preserved.

The site integrates scientific and technological education and eco-tourism.

The park itself, including historic military fortifications, is built on a brownfield that was a steel slag dump. Once 10-meter-high piles nearly encroached on the wetland.

But in 2000, the picture was grim. The site was used as a dump for steel slag from nearby mills. The area was covered by unauthorized construction, junk collectors gathered there, and the place was dirty and dangerous.

Phase I opened in 2007 and the entire park recently opened for the Expo after seven years of work.

Today a winding plank walkway takes visitors through marshes and along the water; they can enjoy the wetland on either side. Small fish swim about, crabs crawl on the mudflats and wing their way above. Seagulls dive downward to catch fish.

There are man-made hills, lawns, waterfalls, streams and gardens, including more than 13,000 trees.

The park has a culture plaza, space for sports, boating, horseback riding, entertainment and picnics. It offers 30 kinds of activities.