That was my thought. Bodies of water are often tricky like that.

When I moved to Canberra it took me several months to realise that the campus map had been printed with a view to fit the campus onto a rectangular piece of paper, and not with a view to making sure that North was at the top. It was only when I realised the sun kept setting in what I thought was North that I twigged, and even then it took a long time to reorient myself.