Nikosandros
Golden Procrastinator
Streets of Silver. This is a really good, very comprehensive city book done under 3e. The city, Parma, is modeled after Renaissance Venice, so it definitely has the river features you're looking for, but may require some cultural amending to fit into a more traditional campaign feel. It was part of a d20 campaign setting called Twin Crowns that was designed to have more of a 16th century "Age of Exploration" feel to it.
I don't know anything about the product in question, but are you sure that the city is based on real-world Venice? I'm asking because Parma is the name of an actual Italian city.