Thanks for the input. I didn't think at all about freezing, but I have to wonder if there would be a problem anyway. Wouldn't the open ended pipe allow for any expansion if it did? Or do you think it would tend to bust the pipe regardless of that? FYI, for the size pond I am building, this would probably be 6 inch PVC pipe and the max depth of water will be about 8 feet. The pond will have an emergency spillway also, so this would be for normal overflow during non-flood conditions.
On the cap at the end of the pipe on the rear of the dam, yes, I would imagine that once you unscrewed the cap, it would fly off, possibly stripping the last few threads, and be impossible to replace until the pond is empty. But that would be the only reason I would want to ever remove it, is for draining. A valve would be a much better solution, and would allow partial draining. But the whole purpose of this was for Mr. Cheapo here to not have to purchase a valve in the first place.
I guess I'll just build it by the textbook, and rely on siphoning or a pump to drain it. I appreciate your replies.
