''A feeling of physical disgust,'' he said. ''It's one thing seeing satellite pictures of the dried marshes, another thing seeing it at ground level.''

Alwash has this year been named one of six recipients of the Goldman Environmental Prize, awards for environmental heroes, each of whom gets $US150,000 ($145,000). When I met him in New York, I asked him what it was like to see the marshes again in 2003.

He started Nature Iraq, a nonprofit group in Sulaimani, and consulted with the Madan, or Marsh Arabs. They had started to punch holes in the walls of the canals built by Saddam, so the area could flood again.

Shortly after the US-led invasion in 2003, Alwash, 54, left Los Angeles and his career in hydraulic engineering to return to Iraq to help save the desiccated Mesopotamian marshland.

He spoke of the horror of Basrah at the time - the stench, the skeletal dogs and cats, the lost beauty of the city - but his optimism overwhelmed the bitter memories: ''There was also this hope in the air, just that everything and anything is possible. So while it was sad seeing your childhood place dead, you come in with this American attitude. It's like: Damn it, we're going to do it!''

Ten years on, the marshes are restored to more than 50 per cent of their original size and the Madan are returning. It has been a monumental job under difficult conditions: war, terrorism, poverty and tumultuous change.

''What was fascinating for the first seven years and even now, I see the Americans making mistake after mistake, but they're not listening to people like me.''

The US dedicated $US175,000 in aid to restoring the marshes but it gave no more, Alwash said. He partly blamed his own conflicts with the US Agency for International Development.

''It was my attitude. I don't like being told what to do and what not to do, and I don't like people who tell me it can't be done,'' he said. ''The experts telling me it can't be done were hired by USAID.''