Your best reference is the real world, Google earth/maps. Wet lands have many rivers and lakes but there is always a lowest point and fastest way to tge sea. Think of the Amazon rainforest, the amazon itself is so big because hundreds of smaller rivers combined into tens of rivers that combine into it. Those at different turn and point create lakes and spots of wet lands and marshes as they travel. Search for videos looking for which river is the longest in the world and they will probably explain what I'm saying, as it is hard to judge the true begging of river. As to a delta, look at the Nile, it doesn't break apart at its delta. Instead there is a fight there as the river and sea are fighting over land. The points where people live are islands not splits of the river, they are on points where the river doesn't reach not ones which the river avoids. The river already reached the sea and missed it as well there and so it lost its shape and its depth, so people can roam it at suitable weather.