Grading Gravel Lanes For Drainage
When your gravel lane starts developing potholes and the mud puddles increase, it's an indicator water isn't running off as it should.
Russ Lanoie is a private contractor with rural home tech.com and says water is the enemy for gravel lanes. But grading and shaping to improve drainage involves more than just covering up the potholes.
"You're supposed to cut to the bottom of those potholes. Otherwise, if you just scrape material over the potholes and fill them in, the potholes will come right back because you never dug to the bottom of the pothole," he says. "The idea is to dig to the bottom of the deepest defect in the road, and then work all the material that you've dug as if it were new material and spread it back on. Then you pull the material from the shoulders to the center, to rebuild your crown."
Lanoie says the recommended pitch for a gravel surface crown is one-half-inch-per-foot-of- width. You could go a little steeper, but it becomes difficult to maintain and vehicles tend to slide off if it gets icy.
Placement of the pitch can be done several ways.
"You can do that all to one side of the road, as in a super-elevated road, or typically from the middle to each side, which is where you get the idea of the crown," he says. "But the crown should not be rounded. The crown needs to come to an "A", to a point in the middle of the road so that the entire pitch is pitched one way or another, and not rounded. The rounded road will pothole out in the middle."
Lanoie stresses that the grading process should never allow for the formation of a ridge, or berm along the side edge of the lane. It will act as a barrier, and prevent water from properly draining into the ditch.
Regular maintenance of the lane should be done as often as necessary to prevent the need for reshaping, and to keep the water flowing away.