There is an outside perimeter 4" pvc drain on the back side of my house buried about a foot or so below surface. The drain point currently just ends near the foundation, meaning it spills out the end and onto the walkway leading to the basement door, sometimes running into the basement. I have an existing underground drain in the same area (for gutter drain) I've made provision to hook into. The problem is the drain point has been compressed to an oval by large stone on either side pressing in. That means I can't attach any rigid 4" piping. Nor can I fit in a 4" flex-drain tube. Any ideas?