WaterCAD 2024 can export contours as native-format Microstation contours. This feature behaves differently depending on whether or not the original model is 2 or 3 dimensional. Since the native contours are 3-dimensional elements they don’t display properly in a 2-d model and reference attachments are created and added to the model.

In a 2-d source model the contours are created in their own 3-d model, which is referenced to the default model. In order to manipulate the contours you'll need to activate the respective model, then make any modifications, then switch back. On the same token, in order to delete the contours you need to delete the model that they're actually a part of.

In a 3-d source model the contours are added directly to the model, and all manipulations can be done directly in the main drawing.