Erlik, It's supposed to be water with mud and what could be green anti-freeze mixed in. In the large render (much too large to post) its possible to see the mud/silt layer in the water, but it gets lost in the compressed and smaller jpg. There isn't supposed to be any oil in the image other then the random dark stains on the concrete and asphalt. (Oil isn't usually green is it? I've never seen green oil myself.) When you first refered to the green water as oil I think this is what confused me since I don't see it as being oil in any way shape or form. Everyone sees things a little different. That's part of the reason for me seeking feed-back on the image. ;) ...get some other view points. ysvry, That's an idea... I'll have to try lighting the storm drain pipe that way in a test image.