I have a potential client who has asked me to solve a drainage issue on his property. So here it is, he lives at the end of a cul-de-sac. All of the street gutters drain into a concrete brow ditch which goes along the edge of his property continues toward his backyard. The ditch then feeds into a 12" corrugated single wall drainpipe that goes down a 100' slope at a 45 degree angle. Well, the problem is that in a big rain the drainpipe gets disconnected because of excessive velocity I think, and cases severe erosion on the slope. The drainpipe is currently unburied and in the bottom of the ravine cased by the erosion. The question is can this drainpipe be expected to stay connected with this heavy degree of slope? Does anybody have any experience with this sort of thing?