Would you ever run a down spout into the drainage pipe behind a wall and daylight at the end? Generally, I would never do this but the situation is this. Retaining wall proposed to run down left side of driveway off house foundation. Driveway slopes down from house and pitches to the right, opposite the wall side. There are 2 down spouts that exit on driveway where the wall is to start. Often, runoff water crosses the drive and freezes at night. I recommended cutting the driveway and burying drainage pipe, then patching the drive. The driveway is a couple years old and the homeowner isn't keen on the patch. I don't blame them. I wish the paving company that did the drive had a little forthought to bury the pipe during the job.