Merge Contour Data

We need to merge two sets of contour data, ground survey and county (GIS) that were provided us. The contours consist of line strings, and I believe they were setup in SS2.  What would be a quick way to merge these two together?  I know I could use the clip reference to hide the GIS where it crosses the ground survey but hoped there is a better way.  We will only use the contours to determine drainage boundaries, so a surface is not necessary.

 

PowerGeopak SS4, 08.11.09.878