Geography Question

[CineastBenRowe]

So this is driving me crazy - all through Act 1 and 2 we are traveling on the north side of the Chionthar river, the Risen Road is on the north side, Moonrise Towers is on the north side, but then cue Act 3 and we are approaching Baldur's Gate from the south, arriving at Rivington and then using Wyrm's Crossing to cross the river heading north.

When (and how) did we cross the river the first time? Did I miss something??

[Hawke]

Between Act 2 and Act 3, I suppose. To avoid the army of the Absolute on the march?

[CineastBenRowe]

That makes sense, it's just weird the game doesn't mention it since it's a big river and crossing it isn't a minor thing.