Think of "User Maps" as a way to record a snapshot of features generated within a map project. You can combine features from multiple projects, edit the features etc within a user map. Depth (or hardness) data is still stored with contours, but these are not displayed on the map. Depending on the export format that you use, labels may display there (e.g. on KML and AT5 maps). You can't edit the depth values associated with contours within the user map.