Driveway Keeps Washing Out

[Currmudgeon]

It looks like regrading your driveway, so it has some crown, will help. If the water runs down the gravel pavement, it will erode the gravel. You want to get the water opff your drive and into a formal drainage system, as quickly as possible.

The driveway should be high in the center, and grade to both sides, or alternatively high on one side and drain to the other. I'd use a minimum cross slope of 2% (1/4 in / ft) and might want to go as high as 4%.

You'll want a ditch on either side to carry the water to wherever it's going. The ditch doesn't need to be big, maybe a foot deep with 2:1 to 4:1 sideslopes, but it should be armored to prevent erosion. Your riprap mught come in handy there, but it's expensice. Depending on your soil, some plastic Turf Reinforcement Mat and some hardy grass would probably be cheaper.

Any place the water crosses your drive, you'll want to put in a culvert or a paved ford.

 

[bnixon]

"Rip rap is big rock.... like you see in lakes around bridges and dams. "

Thanks fivestring, Learn some thing new every day!

 

[surfran]

Another option is to add diverters at various points along the driveway so you don't allow the run off to travel down the driveway very far before diverting into your ditch. There are several ways to do this like speed bumps, covered trenches, etc. but the best one I have seen is from a friend of mine who went to a gravel yard and bought old conveyer belts. Cut the belts about 6-8 " strips the length of the driveway width (taking a slight angle into account). Nail/screw this to some 2x4 and burry the 2x4 in the drive(he rented a trencher for 1/2 day) so that just a couple of inches of the conveyer belt is sticking up. This allows you to drive over, but still divert the water before it can build up to wash away. I think he did his about every 50 feet or so as he has a long drive. Usually the conveyer is pretty cheap(he paid $1/ft for 24" wide) or even free.