BAGHDAD, Iraq (AP) _ For 6,000 years, the river that flows through the heart of Baghdad nurtured the people who live along its banks _ providing water, food, transport and recreation. But three years of war, plus pollution and politics, have transformed the storied Tigris into a stagnant sewer _ and increasingly, into a graveyard for the victims of civil conflict.

Some see it as a metaphor for this troubled country, reeling after years of war, deprivation and misrule.

Police now routinely haul from the Tigris the bodies of victims of sectarian death squads. The bodies of 15 unidentified torture victims were found floating on a single recent day in the Tigris in Suwayrah, 25 miles south of Baghdad, said police Lt. Mohammed al-Shamari.

In a recurring and horrific scene, all _ presumably murdered around Baghdad _ had been blindfolded and bound at the wrists and ankles before being shot in the head and chest and dumped in the river.

In an effort to keep the river channel clear, Iraqi authorities years ago built a series of 14 barriers near Suwayrah, with giant iron nets designed to trap plants floating downstream.

Those barriers have become a ghastly catch point for bodies of victims murdered in and south of Baghdad and dumped into the river. Authorities said that in all, more than 235 bodies have been recovered from the barriers since May.

Baghdad families sometimes make the trip south to Suwayrah to try to identify the bodies found in the river. But many remain unclaimed.

It is a stark contrast to the life of the river before the war's start in 2003.

Not so long ago, fishermen wiled away the hours casting lines into the muddy Tigris waters from the bridges of central Baghdad. Lively restaurants lined the river's east bank.

But the restaurants have been closed for years and the area around them sealed off for security reasons, because it's across the river from the U.S.-controlled Green Zone. The bridges are heavily guarded by jittery police and troops who shoo away fishermen.

``I used to fish in the Tigris in Azamiyah,'' said Saif Hilal al-Azawi, referring to a Sunni district of north Baghdad. ``Now it's impossible because of security along the river. And I can't fish in the south because of the sectarian conflict.''

Those who still try to fish do so at night or before dawn. But that's risky because of the security crisis. Fishermen could be easily mistaken for insurgents planting roadside bombs.

In central Baghdad, not a small boat is to be seen on the river's surface _ a stark contrast to other Arab capitals where rivers are full of small-boat traffic.

Ecologically, the problems of the Tigris literally begin where the river rises _ in the Taurus mountains of eastern Turkey. Melting snow feeds the river as it meanders south across the border into Iraq.

The ancient Sumerian name for the river was Idigna, or ``swift river.''

Now the Tigris is heavily dammed in both Turkey and Iraq, providing water for irrigation. The Turks have built six dams on their stretch of the river alone.

That helps to prevent the destructive floods that once plagued communities along its northern course every spring. But the dams also reduced the river's water flow, increasing the salt content and the destructive effects of pollutants dumped into the stream from the industrial cities of northern Iraq.

Today, the Tigris appears almost stagnant in Baghdad. In the dry summer months when the water level drops, mud islands appear in the channel.

``The level of water is decreasing every year,'' said Moussadaq Dalsi of the Iraqi Ministry of Agriculture. ``Now, the Tigris is a semi-flowing river.''

What the river needs is a thorough cleaning, not only to remove chemical pollutants but more importantly to remove the weeds and vegetation that grow along its banks, Iraqi experts say.

In addition to hindering the flow of the river, the weeds take oxygen from the river and deprive fish of the oxygen they need, said Mustafa Hamid Majeed of the Environment Ministry.

Clearing the weeds and other debris would restore water flow to acceptable levels so that nature could purge the river, Dalsi said.

But many areas are simply too dangerous to send cleaning crews, Environment Ministry officials said.

``Twenty years ago, it was easy to catch fish even with a single hook,'' Dalsi said. ``Nowadays, it's difficult to catch fish with a net.''

The river's growing isolation may be one reason it has become a dumping ground for bodies. Farmers now routinely say they try to stay away from the river, so as not to find the dead.