The next dev build that will include the river tool (3.0 river preview 1) will be available really soon. And by really soon, I mean sometime today. :)
Just writing up a bit about it and then it will drop to the dev channel. Although it has significant issues still, it also is very powerful and should be immediately useful. There are also a host of other very useful improvements (erosion active masking, better curves device, etc etc)
We're very close. There's plenty of documentation, examples, and macros yet to be written, but I'll open up the first dev release of the river tool without those and then add the supporting elements over time.
I'm currently targeting next week for the first dev channel release.
About 6 weeks ago or so a few forum users including me asked for some more updates on dev as well as more forum interaction. That worked well for a brief moment, but it seems that after a month things are back to how they used to be?