For proper feedback, I'd wish for a rendering at least double that size, preferrably even quadruple. Double the size you're thinking of rendering the final scene. But I'll comment from what I can see.
Shadows are looking good. Not a lot of complete blacks, which isn't very natural looking and is the thing I usually notice in a rendering. There always should be at least some level of ambience, reflecting from surfaces and such. And you have.
Textures fit nicely to the scene, good choices all around.
The water needs work. The edges don't behave like water would. The surface tension creates a more clearcut edges to the pooling than this image shows to me. Especially the lower left corner, where just the bulks of iron plating are showing, that doesn't look good to my eye.
The scene looks quite serene without any particles or cloth to indicate wind, so the rippling effect on the water feels out of place in my mind. And to fix it both the things I mentioned(a torn piece of cloth tied to one of the bars? Or maybe dry leaves?) might work.
I can't quite make out the far-right corner of the floor, is that grass or moss? It looks like grass and the coloring suggests so, but grass would require dirt, and the scene otherwise it too clean and not weathered enough to have that much mulch gathering in the corner. Maybe moss? Since its already flooded a bit, and some moss grow on just about anywhere just to spite reason.
Top right, the vertical bar with darker texture: I don't care if that's wood or rusted iron, but the bump map is too crazy for either

Rusty iron is quite smooth, even more so than wood. That looks like hand-thrown cement, that wasn't sanded smooth after construction. Otherwise smooth surfaces suggest this place was constructed with care, so it stands out of place with that much bumpyness.
But overall it looks good, all my complaints are definitely things that you'd expect from an early render and are mostly either detailing or material properties related, so they're easily fixed without even touching the model.
"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."
- Albert Einstein