This does sound like a great project, and your progress is very promising so far. One thing I was going to mention is that the islands in your river look a bit wrong. It might be that they look like they've just been dropped there for no reason. In the only examples of riverine islands I know of (Ile de la Citte and Ile Saint-Louis in Paris, and the Tiber Island which you obvously wold be familiar with) the islands occupy most of the width of the river, and alter the way water flows around them. Eg the Tiber is widest where it passes the island (I'm not doing a great job of explaining myself. If there are any geologists reading this, could they please explain it more clearly). I also doubt those islands would appear where a tributary is entering the main river.

Also I thought I'd mention that many English towns (and this probably applies to river ports everywhere) placed their first jetties not on the main river, but on the tributaries of that river. The reason is that the strength of the current was lower in tributaries, and so provided extra protection for boats (especially in a flood).

Hope those thoughts are helpful and don't cause too much problems. As I said, this is a great idea, and I wish you luck with it.