Filling large gaps between curved geometry using faces? I have this:


And want this, but also with thickness (not shown in photo):


(1) Is there a reasonable way to create it with editable faces and (2) have it be a slightly thick, 3d object without collisions along the edges? I tried doing a Boolean modifier for the faces, however, I could not subdivide or loop cut any at all. I am not sure if it is because the vertices on either sides of each "wave" are in much different places. 

(3) Finally, it would be nice not to have a zillion subdivisions on the faces or loop cuts along the wave, while maintaining the smoothness. 

I created the curved plane using a Path and Bezier curve. I think I could just solidify the curve and then try to fit a seperate polygon along the walls, but this doesn't seem proper.

Any tips would be greatly appreciated. Thanks!

EDIT: clarified question
In case like this it might be easier to continue using curve object for modeling and convert it to mesh once the wave is completed.

Bezier curve objects can be filled to become flat surfaces. It's possible though to do that only when their shape is set to be 2D, i.e. positon of control points is constrained to their local XY axes. You still can rotate curve in Object mode though. 

So grab your curve which was used for wave creating, set its Shape option to 2D and rotate as needed in Object mode. Note - it is important to do that in Object mode as rotating in Edit mode will actually create straight line because movement of control points is constrained by 2 axes.



To give curve thickness use Extrude option in the Properties editor > Object Data tab > Geometry rollout. To control resolution use Preview U option in the Shape rollout.



Once you use everything possible of the curve you can convert it to mesh. Note that most likely you'll need to retopologize the mesh as converted curves often have topology not suitable for anything like later subdivision or beveling.