The Autodesk River and Flood Analysis Module 2018 (aka River Analysis) has just recently been released and has some major fixes that will be very welcomed by anyone who uses this program. In the past there were a few bugs that were extremely annoying that no longer exist. Keep reading to learn what they were. If you aren’t moving to 2018, but you’re still using the River Analysis tools, make sure to read this so you know what to be aware of!

Deleted Last Entity Created

When the River Analysis tools are initialized in a drawing, the last object in the drawing that was created was deleted. That’s right, whatever that last object was – a line, a circle, a surface, an alignment – whatever it was, it was deleted. This is no longer an issue in 2018!

If you’re using 2017 or earlier, my recommendation is to draw a line in your file immediately prior to issuing any River Analysis tool so you know which object will be deleted.

New Reaches Automatically Created

Once the River Analysis tools were initialized any drawing used in Civil 3D after that moment would have a new reach created in it. The symbol for the reach would be placed near 0,0 so it destroys the ability to zoom extents. Not only that, since River Analysis is now initialized in this drawing, it deletes the last entity created. 2018 has fixed this problem!

If you are using 2017 or earlier, my recommendation is to run Civil 3D only for the River Analysis task you have. Don’t open any other drawings. Once you are done with the River Analysis task, close Civil 3D and reopen it and you should be good to go. If you initialize River Analysis again, you’ll need to close and reopen Civil 3D again to prevent it from creating reaches and deleting objects.

Reach Drop-down Inconsistent

The drop-down to select the reach you want to work on has been inconsistent at best. Sometimes it works, and sometimes it doesn’t show up at all. I was never able to figure out a decent work around for that one. In 2018, I haven’t seen any issues with the drop-down not behaving the way it should.

Where to get it?

If you haven’t been using River Analysis but want to, you can install it from the Autodesk Desktop Application. If you don’t have access to this, you can also go to, log into your account, and download it (provided you have the permissions to download and install). Otherwise, ask your software manager or IT department for it.

Wrap Up

If you are using the River Analysis tools, you would be doing yourself a favor and doing the work in Civil 3D 2018. Even if the rest of the project is on a prior version, still do your River Analysis work in 2018, export out the HEC-RAS file, and then import it into a prior version if needed.