This has been very discouraging and rather demotivating, compounded by the fact that we have had so much rain and snow that I have been constantly reminded of it, without being able to do anything about it. It isn't a horrible leak--only a trickle--and only occurs when the rain and snow are particularly heavy; but it is enough that I would wind up with a major problem over time if I don't fix it.
It is totally my own fault--a result of being too hasty! (A lesson which I ought to have learned from Treebeard). The good news is that it is totally fixable--and is not some defect in the structure of the pipe. I have identified the source of the leak, and have determined how to fix it (or rather them--there are two spots). In fact, I did manage to fix one of them already, in fits and spurts during March . I just need the stars (or the sun and clouds) to align again so that I can fix the other side. It would have been nice if the leaks had been somewhere above ground; but no, they have been down at the foundation, where the pipe meets the wall, so I had to dismantle the retaining walls on the two corners (the back side of the hole) and dig out all the dirt to expose the spots. (There are few things more discouraging than having to tear down something you have already built and do it over.)
Looking back now, I can see how I could have totally avoided this problem. I just got over-excited about getting the back wall completed, and underestimated water's ability to penetrate through rock and dirt and squeeze through small cracks--even buried cracks. I said I was an amateur at this, and this proves it. But all is not lost.
Hope remains while the Fellowship is true!