topography and implementation of a canal

Hi,


I need to introduce a Canal in my topography.  The problem is that I have the topographical information from digitized maps (not a DEM but just digitized topographical points and curves) and I have to introduce the bottom of a canal which is about 100 m large for 10 to 15 m deep (to have a design in U).  The bottom of the canal is composed by 3 fixed values and the edges of the canal are quite sharp.

The problem comes when I generate the top of the first layer because and evidently I have an interpolation between my topographical data and fixed data for the canal.

I have tried another think : I could obtain a topo for the first layer without the canal, and I thinked that after I could impose just the values for bottom of the canal in the canal area.  It seems that the only possility is impose the value node by node and not areally and the canal is about 20 km long (perhaps is it possible with polygons but I don't understand how).  ???

All idea or suggestion is welcome

PS: I used FEFLOW 5.2

Have I nice day ! :)

:D

Oups ! Finally I find the solution, it works with "join" and polygons for example and assigning the value for the polygon

Any other solution is always welcome

;)

If the channel bed elevation is not constant, but spatially distributed, you can also use the 'data' option of the join tool (instead of 'const') to do an interpolation for the nodes within a polygon only.