It sounds as though you tried diplomacy and it failed. A second attempt might be to ask the neighbor to attach the two ends of the pipe to another buried pipe that would divert the water to the street just inside his property line. You may present YOUR alternative plan of cutting his trees brancehes back to the property line and trenching just inside your property, if that is not done (you have that right). This would be a major threat to his screening trees that he could simply avoid by adding a few feet of pipe. (personally, I think your neighbor is a jerk and that the people in your town hall are completely wrong about him being able to dump water a few feet from your property). If you see that as a confrontation and you don't want to deal with it, you could build a berm with a sloped swale to divert the water toward the street. My concern from your other pictures is that once it gets to the street it will drain back onto your property because it appears that your proprty is lower than the street. You could also dig a big deep trench and fill it with drain rock to try to get it into the ground.

I wish I could claim the pine cone idea, but I can't. It came from a friend in Bon Secour Alabama who ownes a wonderful historic house there. Lots of wood (a whole 'nother story) and lots of porch bases to protect from splash. He found the idea and his porches are surrounded by berms of pinecones. He even has found sources for pine cones of different sizes and grades his pine cone splashes to cut down all splatter. (It keeps his paint jobs in great condition for a lot longer that any other method.) Greta, I used to use pine needles for mulch on my roses in Houston and later in New Orleans. I knew when the needles would be dropped and I knew to go to the neighborhoods that were piney and collect the bagged up pine needles on late Sunday afternoon after the home owners had raked them up and bagged them for the city to take to the landfill. I'd ask permission and it was never denied. In New Orleans with heavy rainfall and heat the needles would be half gone by the following needle drop; they did act to acidify the clay. The cones were much longer lasting five or six years...so any good they'd do would be long term. With the rainfall down there, the needles were the key to pH manipulation. Ann

Nil, you are so kind and generous to take out time to help a complete stranger; thank you so much! I wish I wasn't so dumb,not understanding the "degrees" stuff (what is 50:1,asks Bart the Dummy?) but your drawing is mega-helpful!!! since you DO understand this stuff written down, whereas I DO need an image. Now, from your drawing, i realize that my slope may not be quite as sharp as that,though it's pretty close: it levels out more or less at the height of the dotted line in the drawing (there's a bull-dozed dirt road cut into the side of the hill at that level, done by the previous owner,which is part of the reason for the bad erosion problems, methinks...) ,so the angle is more or less as you've seen it in your mind's eye. Actually, it's good news to me to know that I can't do deep or wide swales; digging meter-deep-and-wide ditches is a lot of work for a middle-aged, albeit strong,lady to do on her own,though as I assured my DH, I've done harder work for my roses...not to mention the fact that I am by no means sure that the soil is sufficiently deep all throughout the slope to permit such stuff! I gather that what you're saying is that I should think in terms of constructing small, narrow trenches: basically sort of just terraces the entire slope. I was thinking to use a lot of branches to make mounds at the foot of each trench,covering them with gooey clay,holding them in place with short, thick branches stuck vertically in the soil,hopefully directing said trenches in such a way as to diffuse the run-off from the road throughout the slope. Fact is, I've seen the power of the run-off water. I tried to construct "ecologically friendly" steps from the road down into the garden,basically just using the branches-and-earth technique, but it was entirely eroded away within a couple of months once the rainy season began; I was forced to make cement steps ( couldn't do it with rocks; my soil is very, very rocky, but they are these very soft, friable rocks that break up very quickly ;there just are not many true, hard stones ...being an artist, I have tried to make the cement steps aesthetically appealing,but the problem remains). So the next step is to diffuse the run-off into the garden,making sort of mini-swale-like trenches. Did I understand correctly? Thanks once more... regards, bart

"For instance, if you have a moat around your tree and all the water stays inside the moat, fast deluge wont hurt." But with various trees and shrubs in MOST North American climates, this is setting up disaster if heavy rains cause the roots to rot. You can always add water to soil, you can't subtract it. So, there's a tradeoff. Yes, what you are saying can superficially make watering easier and I've done it for things like Brugsmansias before. I have a new hydrangea planted in a slight depression (but roots level) because I know it's already a dry spot under a thirsty Ilex opaca and I have no doubt it will be fine. I would never plant any rhododendron that way. (or even a fancier, rarer hydrangea like a non-hybridized Chinese species. H. sargentiana likes it wet in terms of high rainfall, but DOES NOT like permanently wet feet and hot summers. I had one die in a prolonged rainy spell a few summers ago ago)