3 - Bankfull bench, design profile, and floodplain corridor in Civil 3D

[@nehemiahstewart]

Thank you for the video. Could you pls explain why you are adjusting the radiuses at 1:40. Seems to be a design concept I'm not understanding. Thank you.

[@tailwaterlimited]

You bet! The offsets from the second alignment are used to define our bankfull bench grading. The bankfull bench grading helps shape how the water will act at flows greater than bankfull stage. Initially those flows will be directed towards the inside, or point bar, side of the channel, moving it from the outside bend towards the inside. If the point bar is functioning correctly, water flowing over it towards the inside bend will be shallow enough not to have enough power to move sediment, therefore being a depositional zone. On the outside of the bend, the point bar's function is to scour, keeping the pools cleaned out. Once we use these offsets to create the corridor, the corridor surface can be used as a canvas for using Stream Tools to refine the bankfull channel design which I describe in the next video in the series kzbin.info/www/bejne/aHXHYpmwjp2Xfc0. Thank you for the question and please feel free to reach out with additional questions, or if you need additional clarification.

[@andreataillacq6779]

When I create my offset alignment only one side appears. What am I doing wrong?

[@tailwaterlimited]

Typically that means that there is not a solution for your offset alignment. Make sure that the radii in the alignment that you are offsetting are greater than or equal to your offset distance.