You wind along a path, over oak bridges, beside reeds and ponds. Swans dominate the foreground; a huge variety of ducks land and take off from the lagoon in the background. In the near distance is a green three-storey building with what seems like hundreds of windows. In the far distance a crane works silently, building a village of new houses.
This is not in remotest Norfolk, but in the pleasant suburb of Barnes in west London. Something really remarkable is taking place as four redundant Victorian reservoirs, covering no less than 140 acres, are turned into the ninth Wildfowl and Wetlands Centre in Britain, this one just six miles from Oxford Circus.
The origins of the Centre at Barnes are fascinating. Sir Peter Scott, founder of Slimbridge and the Wildfowl and Wetlands Trust, always dreamed of a WWT centre in the heart of London. In 1974 the reservoirs, just across the Thames from Hammersmith, had been designated as a site of Special Scientific Interest because large numbers of diving ducks wintered there for the deep water and steep sides of the tanks.
Then, in the late 1980s, London's new water ring-main made the reservoirs redundant. Scott and the WWT began to plan the centre and, despite Scott's death in 1989, the trust went into a partnership with the builders Berkeley Homes and Thames Water plc, which owned the land.
Planning permission was granted in 1995 for houses to be built on approximately one fifth of the land. The plan was for pound;11m of the profits from the sale of the new homes to be spent on the basic construction of the centre.
The reservoirs, each five metres deep and encased in concrete, were to be transformed into a complex habitat for wetland wildlife - featuring open lakes, reedbeds, grazing marshes and mudflats.
The water supply comes from the Thames-Lee tunnel, a supply pipe which connects the Thames at Hampton with the Lee Valley reservoirs. One lagoon is maintained at a constant level and can feed all the other areas, each controlled by independent hydrology which allows them to be flooded or drained as required.
The transformation of the site has been achieved - under a stringent planning condition - with hardly any soil or concrete leaving or entering the site. So broken-up concrete from the reservoirs provides the foundations of the path which we're now treading between the lakes, ponds and marshes. This newly-created landscape, even before it's finished, is providing an encouraging habitat for frogs and newts, pipistrelle bats, and for lapwings and great crested grebes.
We reach the three-storey hide, walk up (run, in the case of the four children in the party) to the top floor and suddenly the whole site is laid out with perfect clarity in the winter sun. We can see the Thames, the great bird motorway, from which it is hoped new species will drop in - and perhaps stay - in what promises to be a comfortable, safe and suitable service station or longer-term accommodation. Across the river are the lights of Fulham football ground and the tower at the top of the Ark in Hammersmith Broadway. The site is so big that the hundreds of new houses that made it all possible don't impinge at all.
Much closer is the Peter Scott Visitor centre, which will have an audio-visual theatre, a Discovery building with high-tech, hands-on displays where fibre-optic cables will bring live pictures of birds feeding and nesting in remote parts of the centre and, eventually, in other centres all over the world. Ultimately, schools may make a virtual visit to the web site.
The wetlands don't open officially until 2000 but teachers can get in touch now. Education officers are being appointed and by the end of the year in-service training courses should be in place.
The centre is a wonderfully imaginative project, but inevitably expensive. pound;2 million was raised by the trust last year - including a sizeable chunk of Lottery money. "The interpretation has to be able to compete with London's top museums, and that sort of quality doesn't come cheap," says Doug Hulyer, project director. "We still need to raise pound;2.8 million from corporate and private donors. And the centre will be expensive to run, so inevitably we'll have to charge for admission."
He's confident the money will be raised and as one of the original begetters of the project, he sees its unique feature as being right in a huge centre of population. "It has been a long haul, but it shows what can be done with a brownfield site and a good partnership."
The Wetland Centre, The Lodge, Queen Elizabeth Walk, London SW13 0DB. Bookings, membership, tel: Marie Dowling on 0181 878 8995 or at email@example.com