Adding contrast to outdoor areas?

[GoatLord]

in the above screenshot, I'm designing an outdoor area in UDMF, but given the use of portals and 3D floors, I dont want to complicate the geometry by adding sectors for implied projected shadows. I instead used a lot of dynamic lights, fog and colored lighting to get a really nice effect, but it looks a bit flat. Any ideas for adding contrast? Is it possible the fog is the culprit?

[Marn]

You could use a lighter colored lower texture on the ledge running around the perimeter of the area as well as on the central structure in order to contrast with the ground and the darker upper wall.