NEED HELP DESIGNING STREAM CHANNEL STEP POOL CORRIDOR

[mwaPT95E]

Hi all,

I am working on building a series of step pools in a stream channel after removal of an undersized culvert. I have developed a design alignment, profile, channel assembly, and have created a rather ugly corridor from all these.

I need help on smoothing the top of bank elevations throughout the corridor. Since the channel centerline profile is so undulating due to the step pools,  the top of bank is also very undulating. I would rather have the top of bank be a smooth grade from upstream end to downstream end. How would I achieve this? I tried adding top of bank baselines to the corridor from 2 feature lines set at a consistent elevation. That did not work. 

Moreover, how would I design the assemblies so that the corridor fluctuates in pool width? For instance, the channel should be widest at the pools, and narrowest at the steps. Currently, the corridor is a consistent width. 

Thanks for any help!

[Jerry_Barnes]

For the undulating top of bank elevations, draw profiles in your corridor profile view connecting the points along the banks whose elevations you want to maintain. Now target the elevation to this new profile for whichever subassembly causes the bank undulation and it will smooth it out to the profile you just drew. 

As for the changing width of the pool problem, draw polylines in plan view exactly how you want the widths to change along the corridor. Target the width of the appropriate subassembly to these polylines and the pool widths will change as well. 

Last problem... when you target the polylines for the width of the pool it will almost certainly change the width of the banks as well. You'll need straight polylines in plan view along the banks to target their width. This will make sure they stay where they should. 

[Neilw_05]

I would approach this as a grading project, meaning using feature lines vs a corridor and assemblies. Corridor assemblies are very linear which makes for issues when there is a lot of non linear geometry. You can use feature lines and contours to build the model exactly how you want it, then use alignments to show the surface in profiles and sections and as baselines for survey control. On the other hand, if you need to move things around to get a solution and have to maintain dependencies between the geometry, a corridor would be more useful. Perhaps a hybrid approach would help. Use a corridor to get it started, then dissolve it into featurelines for the detailed grading.