One thing to consider: It is difficult to build a good 2D model from a 1D model cross-section data. Your 3D bathymetry will be interpolated between the 2D sections and my not represent the topography correctly.
But if you really want to try making a 2D model from MIKE11, here are some thoughts:
1. MIKE-GIS?
It would be better if your MIKE11 model was built using MIKE GIS. Do you have data files from MIKE GIS? If you're using MIKE-GIS, you should be able to export your data in a format that Blue Kenue can read. You can then use Blue Kenue tools to build a Telemac mesh.
2. RAW DATA
If no MIKE-GIS, you should start from the "raw data" which shows the X-Z data and chainage between sections. This data would represent the channel better than the "processed data" you've posted. Use a spreadsheet to reformat the cross-section "raw data" as a series of lines using Blue Kenue's I3S format (my preference) or a collection of points in Blue Kenue's XYZ format. I3S or XYZ formats are simple text files and are easy to replicate. You can build a mesh in Blue Kenue from these I3S or XYZ files.
3. PROCESSED DATA
Otherwise, if you can only use the "Processed Data", this isn't ideal for trying to build a 2D model. You will need to use a spreadsheet to build representative cross-sections from the elevation/cross-section data. These representative cross-sections would then be formated as in #2 above.
Sorry, but I don't have access to MIKE11 anymore, and it has been 10yrs since I've used it... But hopefully some of these comments can help.