One of disadvantages of large bases is the difficulties imposed upon the terrain. This is especially true of bridges (and villages among other features) It looks rather peculiar to have a large element suspended over a narrow causeway and should combat occur, disputes can erupt over positioning.
With this in mind I created an 'expanded bridge' over my existing waterway for the large napoleonic bases we use.
The bridge is a solid piece of hardboard with short pieces of resin stone walls set slightly inside the ends so I could paint in the continuation of the latex waterway so it looks like the stream continues 'under' the walls. Effective enough from a distance.
The rivers are from Wizard Kraft link