Building driveway culvert. School me.

Oddly, I have been involved in lots of heavy construction trades but never built one of these. I need to do a quicky until I have to pour a nice concrete entrance. The area is nearing the top of a gentle hill and the ditch is small because there is very little water movement there.

I was going to install an 8-12" culvert pipe but I had a mix of ideas to ensure the entrance handles the traffic. One being to bed the pipe with quickcrete which should case it and improve loading.

I am also having friggin sticker shock on culvert pipe! What do I need here? I have to plan for fully loaded semi traffic on this little guy.

Two or three smaller schedule 40 ABS (like 6 inch) with one below and two above set in road base crushed gravel and sticking out 2 feet on the ends work well.
The small diameter keeps the flow strong enough to prevent settling out and plugging, and they don't crush very easily. Jim

Many governing bodies control the size of culverts. You may want to check with your building permit office.

Check with your local government as most have requirements as to diameter, type of pipe and length. Some local governments will
install the pipe for you so that they know its done right as the ditch drains their road. You don't want to do it twice if the
local government doesn't like how it was done.

If it's near the top of a hill maybe you could get by with a 4 inch pvc, you don't necessarily need to drain the water away right now, just eventually.
I am under the impression that too large a culvert causes flooding downstream.

I asked at work about what it would cost for
a 12"X30' galvanized culvert a couple months
ago, and I think they were $165 or $185. I
didn't think that was too bad, we get no
discounts on them. Central MI.

I work for one of those local governments, Usually We put them in here, but landowners can get a permit and do their own, have to be built to County specs for safety and all of the culverts are galvanized steel or concrete. The plastic culverts don't do well in an accidental or intentional ditch fire. There are places where culverts are not necessary but it all depends on drainage.

If you are just starting to build and are going to be running cement and dump trucks
don't even think of putting one in yet. just put some rip rap rock untill done then put
in your culvert. as for the drive scrape the top soil off and put in a good layer of
number 4s. Will look rough but as the trucks drive over it will pack and lock together.
Then go over it with 57s or Dga.

Well with out seeing it myself i do not have a good idea , BUT never go to small . Keep this in mind once you build up for a drive you are damming up a natural water way , What you may think is a trickle can end up a ragging river in heavy rain or snow melt . Back in the days of the Clinton oil push i installed a lot of entrance ways off of state highways county roads and township goat paths and on back the lease road to the well pad. I have used 13 5/8ths conductor pipe 16 and 18 inch corrugated and up to 8 foot stuff . IF this is at the road then you should talk to the state county or township as to what they want , does it need head wall on the inflow or does it need one on both sides ??. You want to set the pipe on sub soil and it must be compacted in while back filling and it should have atleast two feet of dirt over top PLUS any stone . If this is and entrance and you are going to be bring in semi's then ya need no less the 35 feet but forty is better . As for slag /stone for it to handle heavy truck traffic You want no less the eight inches of #1 stone on sub soil then top that with a #4 stone around four inches of that , then on top of that i used what we called 304 , it is a sorta mix of like a #6 on up to 8X and i would put down six inches of that . when done and compacted in tight i don't care what the load or the weather that drive is there to stay . each and every entrance way i install back in the mid seventys is still there some are growen up in weeds now but even when the frost comes out in the spring you could drive in that lease road with a semi weighen in over a hundred grand and not sink . Now IF you could get your hands on some rail road ballast that is some good drive way stuff .

I'm no fan of multiple small culverts vs one larger one. Why? I'm in a heavily wooded area & the small ones just get plugged continually & then wash them out & you start over.

What you are not saying is the important fact here without all the guess as to what the situation is. Is it on new drive crossing road side ditch? Is it way off road on private property? and how big is the ditch and how much ground does it drain and is it drainging all from the landowener it is to be on or are there other properties involved. BIG difference in what you have to do. If it is back in middle of one piece of private property with NO neighboring owners property drainging through there what you can do is greatly different than a roadside ditch or if it drains multiple properties. So we need details on these points. Some situations no goverment involvement and others could be federal goverment.

Thanks for the thoughts guys. I have determined that our local govt will "install" these but I get to pay for it.

I appreciate the thoughts on ditch fires and I think that will drive us to stay with steel. This ditch is the roadside ditch to a county road and only will access our property. There is a permit process but our county for the most part just wants to discourage shoddy work so I think as long as I build it right, we won't have a problem. I can tell you there is no land that drains into the ditch and my neighbor is at the top of the small hill with no culvert at all. The only thing that ditch drains is itself and half the road crown.

I know there is some math here but I crunch numbers for a living and this seems rather straight forward. I effectively have about 500ft of road and half of the road drains in this ditch so I would account for a conservative 30ft from centerline of road and 500ft length. That would be 15000sf of area so a 1" rain would be about 9300gal of water. I will work the numbers a bit to get a nice low restriction flow and I think 12-15" will do well. A big rain here might be 2"/hr or about 310gpm in that culvert.

Or you could get a 10" rain and wash it out.
A lot of that going on.

A typical corrugated steel or plastic culvert buried properly will easily handle any vehicular traffic you subject it to, including loaded ready-mix trucks, loaded dump trucks, etc..

Make sure you make it wide enough so they can get in and out without running off the edge.