How do I create slices of a topographical mesh? I've been trying to create a topographical wire mesh as shown below to convert to curves later:



Here I have a Bisect Tool Cut in Blender, but as you can see, the Tools panel really doesn't have an option to Create Multiple Cuts like I would want:





But heres an example from Cinema4D below, but I know it's possible in Blender too.



I would then like to select those edges and convert them into splines.



Apologies for the confusion.
Create a plane that is larger than your terrain and create an array in the Z direction. Add a Boolean modifier to the terrain - the plane is used as a cutter. Visually you can create the layers by then adding a solidify modifier...



...but you asked about creating curves so - apply the Boolean and then in Edit mode press P and choose by loose parts. Back in Object mode while all the objects are still selected press ALTC and convert your meshes to curves.