there is a problem with vehicle access to the site, due to the lack of vision, if a car comes over the bridge fast and a coach is turning into the entrance from the other directions there may be an issue, however, this problem was anticipated in the competition brief, and solutions are asked for, maybe a set of traffic lights on the turning with a repeater at the crown of the bridge (or indeed a high light that can be seen as you approach the bridge to stop traffic while a vehicle turns into the site.
I still see that a viable option would be to make a floating visitor centre and dig out a basin at the location for it to berth, then at least if it became unviable at that location it could be moved to a more frequented location and the basin used for moorings. win win