WORK IN PROGRESS: What is wrong with this painting?

I have been given a challenge to reconstruct a scene that has not existed for nearly 2000 years. The challenge of historically accurate representation is the lack of readily available information one can use for reference. No wonder there are research departments for historically made movies. It is not just the landscape one has to worry about, but the materials available for use at the time, and the knowledge to create.

I need to illustrate a Roman bridge created in 105 A.D. over Danube, from what is now Serbia to Rumania. This bridge was completely destroyed, and all that remains are a few archeological scars.

However, the Internet provided me with what I will assume are accurate dimensions of the bridge and information about the construction of Roman camps on either side. Books provided more information. Nevertheless, I feel as if I do not know enough, and unfortunately I cannot afford to spend more time researching the period for accuracy. I have to hope that editors in charge will be so good as to point out any discrepancies in my work, before I completely embarrass myself.

The drawing began with a satellite photograph of the area. Though I am aware that 2000 years of erosion has change the landscape considerably, it is the best visual representation I could come up with.

Then I created a flat dimensional map of the bridge. Inventing some dimensions, because unfortunately they were not included in my research.

With a digital program I placed the map over the photographed area, giving me as accurate representation of the bridge as possible, before adding details and completing my drawing.

However, I have no idea what existed around the bridge and the Roman camps (castrum-s), so I tried to create some cottages and farm land surrounded by a deciduous forest.

I decided on the Autumn scene, because I believe that the contrast will make the river and the bridge stand out from the surroundings.

Now, I have been painting the scene for three days and I'm not happy with it. I think I may have figured out the problem, but for the sake of this blog, I ask you:

"What is wrong with this painting?"