But now, the weirs also catch corpses that float down from the capital, murder victims in the sectarian violence that blights Iraq.

Local police in the nearby town of Swaira say that since January 2005 they have collected 339 bodies of men, women and children from the filters. It's considered one of the highest numbers of corpses found in a single location in Iraq since the U.S. invasion in 2003.

"Every day, we find bodies in the river," an official at the Swaira police force's crime department told ABC News. "Most of them are of Iraqis living in the bloody areas to the south of Baghdad."

Among the 339 corpses was that of British aid worker Margaret Hassan, abducted in October 2004 in western Baghdad.

Identifying the bodies is no easy task. Many have spent more than 10 days in the water. Some are mutilated or have been eaten by fish. Identifying features such as scars and tattoos, as well as distinctive clothing, are sometimes the only means of verifying their identity. So far, only 91 bodies have been identified by their families.

Once recovered from the river, bodies are photographed at the police station, and if they remain unclaimed after a day, they are sent to the morgue in Baghdad.

Most of the corpses are young people who have been shot and then hacked to pieces, according to the head of the Swaira police force, who asked that his name not be printed.