Wetlands are among the most threatened but valuable habitats on earth. To mark World Wetland Day next Wednesday Roger Ratcliffe visits a new one created in Yorkshire.
There are some beautiful stretches of the River Don between its source in the Pennines west of Sheffield and its eventual destiny in the wide Humber estuary.
But in living memory at least, the river has never been famous for hosting a rich variety of wildlife.
Although it flows across a flood plain, the once-boggy mosaic of meadows and pastures – some of which would have resembled the fens of East Anglia centuries ago – is well-drained, and much of the distinctive wetland flora and fauna has long gone.
But times have changed and so has the thinking about the value of these vanishing areas.
The damage caused to wildlife through centuries of reclaiming land for agriculture is now recognised not just nationally but also on a global scale.
Since the adoption of the Convention on Wetlands in the Iranian city of Ramsar in 1971 there has been a greater international awareness of the benefits wetlands bring not only to wildlife but also to humans.
These include the effective storage of water at times of high rainfall, alleviating flood risk, and the cleaning of pollutants like pesticides, phosphates and heavy metals.
They also have an increasingly vital role in countering climate change since they capture greenhouse gases.
And so in Yorkshire, along the River Don, about seven miles downstream from Doncaster, work to partially reverse this process is well advanced on either side of the river between Jubilee Bridge in the west and Stainforth Bridge in the east.
When the work is completed later this year it will be one of the largest new freshwater wetland sites in the UK.
Much of the area here is below sea level and for many years the farmland was protected from high water levels by what locals call cradge banks – raised embankments which prevented the river from overflowing.
The nearest village is Fishlake, mentioned in the Domesday survey of 1086 and once an inland port which exported goods like tanned leather, wool and cloth on boats plying the River Don.
Although the Dutch engineer, Cornelius Vermuyden, unsuccessfully attempted to drain the land, having received orders from King Charles I, it wasn't until after the Second World War that an effective drainage system was created. This was assisted by installing pumping stations in the mid-1980s.
Now, by letting the river flood once again, some of the adjacent low-lying meadows and pastures will revert to how they looked hundreds of years ago, and they will once again support a variety wildlife that was once considered common in this part of the county.
The Environment Agency (EA) earmarked the site for its potential habitat value because it is one of the few areas of the Lower Don where the main flood protection banks are set back from river.
This meant that new wetlands could be created in these large spaces without causing any increased flood risk.
The EA's Jenny Grinter, one of the team which has led the project at Fishlake, says that it involved creating openings in the cradge banks along the Don. When the tide from the Humber pushes non-saline river water upstream it will flood into adjacent fields, creating about 150 acres of new wetland habitat.
Before this new work, the tidal pushes of water would have made the river overtop the cradge banks once or twice a year. Now, however, the Don's waters will spread over adjacent pastures three or four times a month.
The Fishlake site has been split into seven "cells" on both sides of the Don, each one having its own specially engineered way of filling with water and then draining back to the river.
Over time the standing water, which should be no more than 15 inches in depth, will start to host traditional wetland reeds, rushes and wildflowers such as Ragged Robin and Yellow Flag Iris.
New reedbeds have been created in some cells to provided nesting sites for birds such as reed bunting and reed warbler as well as spawning grounds for fish.
Each cell will be a target for specific wildlife interests. For example, one is designed to support wading birds and fish, another is already proving attractive to water voles because it has been engineered to provide the more constant water level that they require.
There are designated fish refuges in the scheme so that fish will not be left stranded when the water drains back into the
They will have sufficient water to keep them alive until the next flood gives them an opportunity to rejoin the river.
There are also special fish-friendly outfalls cut into the bank to make their escape easier.
In addition to the reed-nesting birds, other species likely to benefit from the project are common snipe, redshank and lapwing.
Already, redshank and common teal have been attracted to the new marshy ground.
Several parts of the site have been left raised to keep them above the water level and provide safe nesting grounds for lapwings.
Jenny says: "We didn't want the water to be too deep because it would flatten everything.
"We wanted to make the site sufficiently wet to appeal to the wildlife we hope to attract."
After serious flooding of the River Don further upstream in 2007 residents in the village of Fishlake were initially worried that the breaching of the cradge banks would increase the flood risk.
But the Environment Agency insists that this will not be the case and that protection will be maintained.
"We ran a complex model and the work we've done has made no change to the flood risk in this area," Jenny says.
As a result of the consultations and meetings, better access is being provided so that local people can reach the river.
A new right of way is planned along the floodbank from Stainforth Bridge, to Jubilee Bridge.
There will also be interpretation boards to tell people about local history, the new wetland wildlife, and shipping on the river.
The work has cost the EA 750,000, and Natural England provided a further 100,000 through its Wetland Vision scheme.
Jenny says it was never the EA's intention to create a wetland that would become a tourist honeypot, like the RSPB's nationally famous reserve at Blacktoft Sands near Goole.
"For us it was more about creating a good wildlife habitat and providing somewhere for local people
The Fishlake project is part of a larger scheme known as the Humberhead Levels Wetland Vision.
This aims to recreate significant areas of wetland by joining up isolated wetland fragments in North and South Yorkshire, Nottinghamshire and Lincolnshire.
It is costing about 1.7m and almost 500 acres of new wetland are being created.
The work is being carried out by a partnership that includes Natural England, the Environment Agency, RSPB, the Wildlife Trusts of Yorkshire, Lincolnshire and Nottinghamshire, and the Burnet Heritage Trust.
The trust is chaired by the writer and Last of the Summer Wine creator, Roy Clarke, who lives near Goole.
Wet wonderlands for wildlife
Wetlands include swamps, marshes, bogs and lowland peat moors. By the mid-1990s half of the wetlands on Earth had gone. World Wetland Day, on February 2, marks the first major global initiative to reverse the process – the adoption of the Convention on Wetlands in the Iranian city of Ramsar in 1971. In Yorkshire and Humber, the Fishlake project (see story) is part of a larger scheme known as the Humberhead Levels Wetland Vision, which aims to recreate significant areas of wetland by joining up isolated wetland fragments in Yorkshire, Nottinghamshire and Lincolnshire.