driveway water pipe crossing how much cover on plastic pipe

[oosik]

About a mile up the county road is a creek going under the county road. Two 4' diameter pipes under the road. Because of the grade there is over six feet of cover over the pipes.

For over thirty years - no problems. Then five years ago a family of beavers moved in - upstream of the county road. In a heartbeat they had both culverts plugged. Initial answer - large tracked backhoe.

After the county unplugged the culverts for the third time - Fish & Game live trapped and relocated the beavers.

Amazing - nobody was concerned until the creek had backed up and was overflowing the county road. They darn near lost the county road at this point. The upstream pond became enormous. The beavers were in seventh heaven.

 

[coffeeman]

They make or you can make a smooth pipe grate, it is several pieces of 3/4 inch pipe or smooth rod they are spaced 2-3 inches apart.
The length can vary but the longer the better, when placed in the ditch at a very shallow angle the water can push any floating debri up and past a culvert.
Doesn'r bo anything for mud or rocks.

Great idea. Easy peasy.

I have one crossing and want to put 24' pipe. If I don't have enough cover can I raise road about 6 inches or so gradually to make give support. will 12 inches of cover be adequate.
I will use blacktop millings as support instead of gravel. Also have some slag left over from another project.

Have good day................Coffeeman