Creating custom arc shapes (multiple bumps) I'm a beginner at 3D modelling and currently stuck on modelling an arc for a furniture piece i'm working on. As per the image below, I thought this would be a relatively easy piece to model but of the methods i've try, none of them seem to be working!  


The closest I've gotten is first creating a rectangle, giving it some loop cuts and performing the warp function. But when I try to create the additional bumps, I'm assuming the lack of vertexes made it impossible to smooth out those sections. Does anyone know what a possible way of creating an arc like the one I attached may be? Any help would be greatly appreciated!
Use NURBS Curve to model the lower part

Still in Edit Mode add another NURBS curve and model the upper part or the 180° arc
Convert both to mesh, close at the bottom with edges and fill
Extrude these bottom edges
Y-Extrude the whole model