How big to size the pipe ....

[warhammer]

For a gravel driveway that has to cross a wet weather creek.

Other than clearing the brush to see whats there, the creekbed is as it was carved by decades of water flow. Water gets going through there pretty good when it rains.

Any thoughts?

WarHammer

 

[EddieWalker]

No way to say for sure, but culverts never fail if they are too big. They fail from being too small and/or not having any protection at the ends for erossion.

Just off hand, I'd be worried if you went with 18 inches. That's a pretty good sized culvert, but 24 inch should probably be a minimum size. Then consider rip-rap or cement to hold the water back from eroding along the sides of the pipe. The back end seems to get it the worse, so be sure to do both sides.

What is the picture of with the culvert in it? Is that on the same drainage?

Eddie

 

[jinjimbob]

The bigger the better, and I'm only talking from an environmental position, otherwise it'll turn into a high pressure pipe.
Check with your local building office, you might need permission for anything.

 

[LBrown59]

The bigger the better, and I'm only talking from an environmental position, otherwise it'll turn into a high pressure pipe.
Check with your local building office, you might need permission for anything.

i'v put in several drain pipes on my place no permission required.
I love freedom.

 

[warhammer]

The drainage with the culvert installed is up close to and parallel to the road. The county specced it and installed it. I bought the pipe from a vendor and had it delivered, its 36".
The county did the installation and provided the fill for $5 per foot which worked out to $150.
They only do the road drainage or I would have asked them do the creek crossing as well.

I was thinking 4 feet or so diameter for the creek crossing.

WarHammer

No way to say for sure, but culverts never fail if they are too big. They fail from being too small and/or not having any protection at the ends for erossion.

Just off hand, I'd be worried if you went with 18 inches. That's a pretty good sized culvert, but 24 inch should probably be a minimum size. Then consider rip-rap or cement to hold the water back from eroding along the sides of the pipe. The back end seems to get it the worse, so be sure to do both sides.

What is the picture of with the culvert in it? Is that on the same drainage?

Eddie

 

[CurlyDave]

Check out this publication: A Landowner's Guide to Building Forest Access Roads - Introduction.

Especially look at the section on "Sizing pipe culverts".

 

[warhammer]

Thanks for the great link. There is lots of good info there.

I am going to have to get a handle on how many acres drain through there.

WarHammer

Check out this publication: A Landowner's Guide to Building Forest Access Roads - Introduction.

Especially look at the section on "Sizing pipe culverts".

 

[EddieWalker]

Something else to consider is covering up the culvert. A big pipe will take allot of material to cover it and have a gentle slope going over it. If you use a four foot culvert, you will want at least two feet of dirt over the top of it.

How wide is the creek? Have you watched it flow after a heavy rain? The rains that drop allot of water really fast are the ones you need to plan on when sizing the culvert. I can get 2 inches of rain in half an hour and have had several storms drop 5 inches in a couple hours here. I have culverts from 12 to 18 inches on my place, but he county said I had to put in a 24 inch culvert on my driveway. This is all runoff and there are no creek crossings.

Eddie

 

[warhammer]

The creek bed where the crossing would be is about 4 feet wide and about 3 feet deep. About 75 feet down the creek it passes under the road.
I have not seen it after a heavy rain but have been told that "quite a bit" of water runs through there.
Might just have to leave it as-is until there is a good rain and see for myself.

WarHammer

Something else to consider is covering up the culvert. A big pipe will take allot of material to cover it and have a gentle slope going over it. If you use a four foot culvert, you will want at least two feet of dirt over the top of it.

How wide is the creek? Have you watched it flow after a heavy rain? The rains that drop allot of water really fast are the ones you need to plan on when sizing the culvert. I can get 2 inches of rain in half an hour and have had several storms drop 5 inches in a couple hours here. I have culverts from 12 to 18 inches on my place, but he county said I had to put in a 24 inch culvert on my driveway. This is all runoff and there are no creek crossings.

Eddie

 

[KentT]

Based upon that bridge -- assuming it's where the road crosses the creek just a bit farther down -- I'd be concerned about a 4' culvert being big enough. Just looking at the pictures -- I'd be concerned about even a 6' foot one. Maybe two 4' ones, side-by-side, embedded in a concrete wall on both ends to control erosion... Hard to tell just by looking at the pictures.

If you'll examine that bridge closely, you can likely see the high-water marks on the concrete. That would tell you how much water you might have to deal with...