Flight of the Marsh Arabs.

Saddam Hussein's plan to drain Iraq's historic wetlands will have diverse and devastating consequences, the first and most obvious of which has been in terms of human life.

At the beginning of 1993, farmer Abdel Karim was looking forward to a record crop of dates from his palms in the southern Amarah marshes, near the town of Qurnah. He had heard Iraqi Government engineers had dammed and diverted a series of lakes and rivers in the northern Amarah marshes, some 60 kilometres north of his home. There were "many stories of villagers being forced out of their homes by the army," he said. But, like the other Marsh Arabs, or Maadan, in his village, 60-year-old Karim pushed these rumours to the back of his mind. Whatever was going on up north was not affecting him, he decided.

Twelve months later, he is still coming to terms with the scale of his misjudgement. Because, like thousands of other Maadan, Karim, his wife, and their 13 children have been forced out of their home by the government's drainage schemes and the ongoing military clampdown in the central Amarah marshlands. Today, they are in Iran.

From late-March onwards, water levels in the lakes, channels and semi-permanent swamps surrounding Karim's village started to decline alarmingly, he said. "Drinking water became more and more scarce. My date palms were dying one by one." By late June, with no sign that things would change, he decided he had no choice but to leave the village where he had spent all save the first 10 years of his life.

It was three months since Karim had fled when he told me his story. But he had only been in Iran for a month. For the first eight weeks, the Karim family had scuttled from place to place to avoid Iraqi patrols.

Arrest almost certainly meant imprisonment, said Karim. "Anyone caught outside their tribal area without good reason is a suspect," he said. At one point, the family considered returning to their village. But then they met a relative who told Karim that "all the mudhifs |reed houses~ in our village have been destroyed."

We spoke as Karim and his wife waited for their 15-year-old daughter to be seen by a doctor in a clinic in Hoveyzeh in southwest Iran. The clinic, run by the Amar Appeal, a British relief charity chaired by the MP Emma Nicholson, is just 15 kilometres from Iraq.

Other families waited quietly nearby. Many of them had only reached the sanctuary of Iran a few days before and they were still being sheltered at a temporary camp at Himmet, just inside the border.

With the Karim family came Rysan and Aisha, their eight children and 20-year-old Hamza with his young family. Since mid-1993, over 7,000 Iraqi Shiites have made the same journey to Iran, most of them Maadan. This influx follows that of almost 50,000 Iraqi Shias the Iranians have sheltered since the collapse of Shia uprising in 1991. Including refugees from the eight-year war with Saddam Hussein's regime, Iran plays host to an estimated 1.5m Iraqis, most of them Shias from the south.

The Iranian Government insists that it will continue to pay for the shelter of its co-religionists. But with the world's largest population of refugees - 4.1m - there must be limits to its largesse.

However, the refugee flow into Iran is unlikely to stop and could expand dramatically. There may be as many as 50,000 people in the marshlands who have lost their homes but remain trapped in the region.

According to information from recent arrivals in Iran and the reports of "behind-the-lines" doctors who provide medical assistance to the inhabitants of the Iraqi marshes from their bases just inside Iran: "There are thousands of refugees who are being sheltered by other villagers in more isolated areas of the Amarah marsh,", says Abu Sallah, a doctor who spent most of October in the marshlands.

Dr Sallah, himself an Iraqi refugee who fled after the collapse of the 1991 uprising, claims many of these people want to seek refuge in Iran, but have been prevented from doing so by Iraqi troops stationed in the Hawizah marshes near the border.

The reclamation programme is making the job of policing the border marshlands progressively easier, because there are fewer channels and open stretches of water on which boats can be used, the normal mode of transport for the Maadan.

On foot, not only is it harder to escape Iraqi patrols, but would-be refugees often have to struggle through hip-deep mud and then swim to reach Iran. Many of the refugees who arrived in Iran in August and September last year claimed to have lost relatives and friends through drowning during their flight. Nonetheless, small groups of Maadan and other Iraqi Shias continue to make this perilous journey and succeed in reaching Himmet and other crossing points, such as Ummanaj.

That the Maadan have to even consider border checkpoints is a mark of how Saddam Hussein's Baath regime has got the better of them.

Before it imposed its will on Iraq, they could pass back and forth across the marshlands of the southern Iran-Iraq border in their canoes - known as mashufs - at will.

But Maadan such as Abdel Karim now sheltering in camps in Iran fear it is more than the freedom to cross borders they have lost, they believe the survival of their 5,000-year-old lifestyle is at risk. United States satellite images show that 40% of the Amarah marsh is now depleted.

Large chunks of the Hawizah marsh on the Iraqi side are also being turned into dry land. "It is the first time that man has deliberately created a drought," was how one recent arrival saw it. And according to the former Iraqi nuclear scientist, Dr Hussein Shahristani, who has been following the development of the drainage schemes since he escaped from Abu Ghraib prison near Baghdad in 1991, this man-made drought is set to expand still further.

In the last few months, construction of a new network of embankments and drainage canals has begun in the section of marsh just north of Qurnah, where Karim used to live. Without water, the Maadan's already precarious existence in the southern marshes would become impossible.

Iraqi opposition groups say the Baghdad regime's engineering schemes are part of its plan to bring the traditionally independent-minded inhabitants of the marshes under its control. Draining the region will make it easier for troops to harass rebel groups and harder for fugitives to escape. Iraq's Ministry of Agriculture and irrigation dismisses this. A spokesman claimed the water works are an essential part of Iraq's long term agricultural development programme. They are designed to cleanse thousands of hectares of farmland that have become encrusted with salt after years of over-irrigation and to provide more irrigation for farmers.

No-one contests that Iraq needs new water sources, or that work to achieve these ends has been underway in the country for decades. Water experts counsel caution in putting the blame for the depletion of the marshes entirely at Baghdad's door. Turkey's multiple-dam project in the southeast of the country has reduced the flow of the Euphrates by a third since the 1970s. And they say this is bound to have had some affect on water levels in some parts of Iraq's marshes. The engineering works that most concern Iraqi dissidents are those that have largely been started since the Kuwait war in the central and northern Amarah marshes, near the River Tigris. These include the diversion schemes that Karim first heard about in early 1993 and a 50-kilometre canal on the western side of the Tigris that runs south to Qurnah.

Opposition groups say there is little evidence of newly reclaimed areas being put to agricultural use in the Amarah marshes. Moreover, the implementation of the engineering schemes has been accompanied by a massive troop build-up, not something one would normally consider necessary for agricultural development projects.

Baghdad admits it has stepped up military activity in the region since the middle of last year. But it says the marshes have become a haven for "brigands and criminals" and it is not prepared to let this continue.

However, in his report to the United Nations General Assembly last year, Max van der Stoel, the UN special rapporteur on human rights in Iraq, described the use of military force in the marshes as "evidently disproportionate" and said this indicated "that the aim is not only to subdue criminals in the area, but to subdue the whole population."

If the claims of recent arrivals in Iran are true, Baghdad's tactics in the marshes have included the use of chemical warfare. In an attack on the Abu Zergi marsh, 25 kilometres northwest of Basrah, on 26 September last year, Iraqi troops are alleged to have fired mortar shells containing the poisonous gas phosgene, a substance not used in warfare since the World War I. But phosgene is used in a variety of basic industrial processes and so the Baath regime could have manufactured its own supplies without breaking the UN chemical weapons ban. Because of its location deep inside Iraq, eyewitness accounts did not reach the outside world for over two weeks. And UN inspectors did not investigate the allegations until mid-November 1993, seven weeks after the attacks were supposed to have occurred.

So long after the event, it was hardly surprising that the inspectors said their initial findings were not conclusive. But many observers of Iraq have been sceptical about claims the Iraqis have used chemical weapons again.

Partly, this is because of suspicions about the reliability of some of the opposition groups making the claims. But it is also because they do not believe Saddam Hussein would hand the UN such a clear-cut excuse to maintain sanctions against Iraq which he has been lobbying hard to have removed.

But as so many times in the past, the Baath regime appears to have two faces. Towards the end of last year, it was showing an increasing readiness to comply with the demands of UN weapons inspection teams. But there has also been a significant upsurge in Iraqi violations of the redrawn Kuwaiti border.

Moreover, Baghdad newspapers are once again describing Kuwait as Iraq's 19th province. Middle Eastern diplomats with missions in Baghdad say this truculent stance reflects the fact that Saddam Hussein's regime is much more confident of its long-term survival than it has been for some time.

That will be unwelcome news for the thousands of Iraqi Shias now sheltering in Iran. Almost all the adults interviewed among the 8,000 residents of Ashrafi Esfahani camp, the largest for Iraqi Shias in Iran, were starting to believe they would never return to their country. But these people have been in this dusty camp near Dezful in Khuzestan province for over two years. The abnormality of life as a refugee is becoming normality.

Perhaps because he has not experienced it for so long, Karim remains adamant that he will return to the marshes and rebuild his life again. But "only when Saddam Hussein has gone."