One of the few successes of the Iraqi governments since the fall of Saddam Hussein has been reversing one of his great crimes: the draining of the marshes of southern Iraq and the destruction of the unique water-born civilisation which had survived there for thousands of years.
Now this achievement is in doubt. A prolonged and devastating drought, combined with the building of dams on the upper reaches of the Tigris and Euphrates rivers in Syria, Turkey and Iran, is reducing the water flow once again and the marshes risk disappearing, possibly forever.
Once double the size of the Everglades in Florida and home to 300,000 people, the marshes nearly vanished in the 1990s when they were drained by Saddam Hussein to stop them being used as hideouts by anti-government guerrillas. But as soon as the Iraqi dictator was toppled in 2003, the marsh people tore down the earth ramparts his engineers had built and water once again flowed into the lakes and reed beds.
The marshes revived surprisingly quickly as their people returned from the slums of Basra to rebuild their old villages, fish in the shallow lakes and tend their water buffalo.
The rebirth of the marshes, fed by the Tigris and Euphrates and close to the legendary site of the Garden of Eden, seemed to be one of the few undoubted successes of post-Saddam Hussein governments. By the end of 2006, more than half the marshlands had been restored. The success did not last.
Over the last two years the marsh people have once again seen the water which they need to survive become shallower and more brackish.
"A few years ago, the marshlands were green and full of reeds and papyrus but now they are almost dry," Abdul-Khadum Malik, the mayor of Chibaiesh town in the marshes near the city of Nassariyah, told the UN.
"If the situation continues like this, all life in the marshlands will quickly die out." He said that dozens of families were already leaving because they could not find fresh water to drink or fresh reeds for their cattle and buffalos to eat. The same pattern is being repeated across the marshes as thousands of people once again take flight.
The reason this time why the survival of the marshes and their inhabitants is threatened is that Turkey, Syria, Iran – and to a lesser degree Iraq itself – have been diverting water from the Tigris and Euphrates for agriculture and to use in cities. More dams have been built across the upper reaches of the rivers, on which the civilisation of the Mesopotamian plain has always depended. That diversion of water has been exacerbated by a prolonged drought.
The Greater Zaab river, which flows out of the mountains of Iraqi Kurdistan, is one of the main tributaries of the Tigris, joining it just south of the city of Mosul.
At this time of year the Kurdish mountains should be white with snow and the hills and plains beginning to sprout green grass. Instead the lack of snow and rain means that the mountains are bare rock and fields and pastures lower down are a dusty brown. Annual rainfall in Iraq, as a whole, is down by 50 per cent in recent years.
The river should be hundreds of yards broad at the bridge at Kalak, between Mosul and Arbil. Now it is not the roaring torrent of earlier years but a placid stream. The reduced flow of the rivers in northern Iraq is reflected by the amount of water reaching marshes in the far south of the country. Osama Witwit, the head of the Reviving Marshlands Centre in Nassariyah, the province in which half the marshes lie, says that the marshlands are getting about 42 cubic metres of water a second, down from March 2007 when they were getting about 250 cubic metres.
The lack of water is not the only problem. The quality of the water has deteriorated, contaminated upriver by sewage, high levels of salinity as well as pollution from pesticides and untreated industrial discharge. Two-thirds of the waste water and sewage produced by six million people in Baghdad goes untreated straight into the Tigris and Euphrates. Only one in five families outside Baghdad has access to functioning sewage facilities.
As a result, the marsh people – although they live a semi-aquatic existence – are desperately short of drinkable water. At risk is a unique civilisation which has existed in southern Iraq for thousands of years. Assyrian stone carvings from ancient Nineveh picture their kings triumphantly slaughtering the people of the marshes who are shown living in distinctive reed houses and rowing their slim canoes. In the first years of Saddam Hussein, large colour photographs of the marsh people adorned Iraqi embassies and cultural centres. But after the start of the Iran-Iraq war in 1980, the eastern marshes became the scene of heavy fighting and many people fled.
Worse was to follow. The marshes had always been a redoubt for bandits, rebels and army deserters because they were difficult for regular police and army to penetrate. The reed beds made good hiding places. During the Shia uprising in 1991, some of the guerrillas who briefly captured Nassariyah came out of the marshes nearby. When the rebellion was defeated, the survivors fled back to them. In retaliation for the uprising, Iraqi forces randomly shelled the marsh villages, machine gunners fired streams of bullets into the reed beds and there was an economic blockade of the area.
As a final solution to the problem of controlling the marsh people, Saddam Hussein decided to destroy their habitat. Canals and waterways were driven through the marshes to drain off the water, and the land was given to Saddam loyalists and sown with crops.
In the course of a decade, an entire ecosystem was destroyed. Using satellite images, the UN Environmental Programme (UNEP) found that by 1991, about 90 per cent of the marshlands had been lost thanks to Saddam's scheme.
The tribes of the marshes were among the poorest in Iraq. Evicted from their villages, they mostly went to live in shanty towns in Basra, Nassariyah, Amara and Baghdad, where they swiftly acquired a fearsome reputation for violence and criminality. When the old regime fell, they immediately started demolishing flood gates, dams and embankments to re-flood the area where they once lived.
Three years later UNEP proudly announced that the total surface area of wetland vegetation and water in December 2006 had returned to 58 per cent of what it was in 1973-76 before the draining started. But this turned out to be the high tide of success in reviving the marshes.
The water in the Tigris and Euphrates rivers has remained notoriously polluted. At one stage, imams forbade the faithful from eating fish on the grounds that they might have been feeding on the thousands of dead bodies thrown into the rivers during sectarian massacres in central Iraq. One of the main causes of death among children is drinking contaminated water. Cholera made a comeback.
The people in the marshes want the government to build dykes down stream to raise the level of the water in the lakes which sometimes have only a foot of water in them.
The government says that holding back the waters is more complicated than the marsh people imagine.
But without drinking water or fresh reeds to feed their buffalos the people of the marshes will soon return to the city slums and abandon their attempt to restore their ancient way of life.