Hi guys, here is a breakdown of my scene so far.I use Lightwave 3d, but the aim of this breakdown is that it might share some ideas that could be used in any 3d package.I love working in Lightwave, it’s very user-friendly and the tools are easy to comprehend and use.For those of you that might be interested, i have added a link to an interview that 3D World Magazine had with me on the use of Lightwave in our animated short film, “Hooked”, which also takes place underwater.
http://i1241.photobucket.com/albums/gg508/bencpr4/HookedArticle.jpg
I would like to point out that this is not the final layout that i’m using for my scene.I start off with a basic scene so that my test renders go nice and fast and when i’m happy with the general lighting setup, i move on to adding additional geometry detail.
Something that definitely helps alot is if we get some good reference of an underwater environment that’s more or less like the scene that you want to achieve.Study the physical properties of what you see.I found it useful to write down specific elements that need to be achieved.
The first thing that i focused on was the fog volume that obscures our view as we look off into the distance.This definitely helps create the feeling of mass that the water has, water is transparent, but it has all sorts of tiny bits of plant matter and little grains of sand that the current could quite possibly have scooped up from the riverbed.
In this image we have the distance fog that i added for the general water mass.I selected a bluey green colour, purely because i find it aestheticly pleasing.You can do your own colour based on your taste.Not everyone will paint the same picture.My ref pic had more of a browny colour to the water mass and less fogginess, but this is now where i take artistic license and tweak it to my own taste.
http://i1241.photobucket.com/albums/gg508/bencpr4/1_Dist_Fog.jpg
My environment fog was created in 2 passes, one for the water mass and one for the riverbed floor, where i have ground fog to try and subtly give the idea of soil sediment being present in the water.
http://i1241.photobucket.com/albums/gg508/bencpr4/2_Soil_Sediment.jpg
And here are the two fog layers combined.
http://i1241.photobucket.com/albums/gg508/bencpr4/3_Combined_Fog.jpg
Here are my settings for the fog in the screen capture.
http://i1241.photobucket.com/albums/gg508/bencpr4/4_Fog_Settings.jpg
And here are my settings for the water surface.The settings were boosted a bit and also tweaked not according to scientifically correct settings, but settings that i think looks artisticly pleasing.The settings were pushed so that the water still looks right through the fog, with my standard settings the water looked somewhat dull, but amping it up to taste kept the water looking right.Bump was added to the water surface, a procedural turbulence texture within Lightwave.I did find however that the bump wasnt enough to make my specular light react properly with the water surface.I then added the procedural texture as displacement to the water surface and voila!
http://i1241.photobucket.com/albums/gg508/bencpr4/5_Water_Settings.jpg
I hope this information is of some use to you guys, please let me know if there is anything that’s not clear or sounds strange ;)If there is anything else anyone would like me to share please let me know, i’m not sure if my methods make sense, but i usually use my tools to achieve something that i think looks good, although it might not adhere to certain scientific laws 
Thanks guys,
Ben.