Batch change polylines elevations

[hrast]

Hi there,
I have a certain task I need to do and trying to figure out the fastest way to do it. Lets say I have several dozen polylines and I need to add certain elevation to each one. I would use them as contours in the next step for creating surface. Trouble is that I will have to change elevations to the whole set of polylines dozen of times. Is there way to get some sort of table which would list all of my polylines with column stating their elevation and where I would be able to change elevation to whole set of polylines by copy/pasting column with values from excel for instance?
Thanks in advance !

[hrast]

Hi Neil. Just thought I would attach screenshot of the final result of one of the runs. It was possible based on help I got here.

White line is zero contour  (flood line) of an volume surface created based on terrain surface and water level surface. Water level surface was created based on contours which got elevation assigned from results of a river hydraulic calculation, the way you have described. Finally, pastel colors are elevations of a volum surface. Thanks once again !

[Neilw_05]

I'm impressed that you were able to figure out this complex workflow given the limitations of the forum as a source for guidance. It is a testament to your perseverance and ability to grasp a concept. I just hope the investment in time pays off somehow.

Good job!