CIG stated long ago that rivers tech was under development, I'm very happy in what they show in the last ISC, that tool is really amazing even if it still have some tweaks to be done.
Can't wait for CIG start to actually implement rivers and in general flowing water (lake, waterfalls etc..) into the planet, that will add a really important player on the realism and immersion of the planets.
BTW, as the tool has been described I can see those logics being implemented and adapted also for road deployment: where for rivers the tool detect and erosion are, for road can implement a tunnel or a bridge for example, where for rivers automatically deplooy a different enviroment type, for roads can deploy lights, buildings, rest and gas stations...