Aquaritis, even though that wasn't the point of your post, I have thought of making my rivers more windy like that. I was recently getting directions on Google Maps and noted how squiggly, wiggly, and contorted a lot of real rivers are. Mine are kind of boring in contrast. But, clearly the elevation (and rockiness?) of the land has something to with that. I'll read more about river placement before I get too crazy.
Maybe my fault not said that i was mentioning your lake. Looks like the river is feeding the lake, like your map.