Hey thanks for the suggestions/feedback guys. The culvert is actually 8" and even with heavy rains there's very little flow for whatever reason - not much runoff in spite of what it looks like. It's not an extension and I just added it before I filled with what I've got. I'll look into a brush guard for it - good idea since it's in the woods and there's lots of leaves and sticks. This is our main driveway but we've got a backup barn drive we've been using. Hadn't even considered making this thing wider - sounds like a good idea for a long-term temporary deal. I know there's going to be erosion and subsidence - that's a given. I guess that's what I'm hoping for though, is that I can get away with it for a while.
DonoBBD, we do plan to use over the winter but in the last 20 years we've had only two major snow storms and it's likely to be more rainy than snowy here. There'll be some 20* mornings, but hope I can get some big rocks on there, or maybe the recycled concrete. There's a guy less than 5 miles from the house that does just that, but I'm not sure if he's got stuff as small as 4". But he's close which may mean cheap delivery. I hadn't heard about the sharp edges before, but it makes sense. The question is whether this is going to be a mess when it's wet. The nice thing about cold winters is that it's frozen, but in the later afternoon it's a soupy mess without rock on it. Sounds like that will cause the rock to just depress and then I've got a mess. How much rock do I need to dump on topsoil, or would it be better to get all that junk out of there and just go with some recycled concrete fill instead. It's going to be a lot of work to get all that out of there, but I had some bad advice on even doing that in the first place.
