Can irrigation equipment damage roads?

Recently, a newspaper editorial admonished farmers in our area for allowing the irrigation sprays to hit over the fence onto roads, claiming that the water causes erosion and damage to the asphalt. I’ll admit that rain falling from a thousand feet or so has a significant impact due to gravitational acceleration of water. But irrigation sprays would hit the road from a height of about twenty feet at about a 45 degree angle. Assuming an average PSI of 50 from the irrigation units, hitting the road approximately 10 times a minute for about six hours per day, is significant damage really possible? I approximate that about a ten foot stretch of road is hit with every pass of the sprinkler unit.

Slow news day?

I would think the angle of the water hitting the edge of the shoulder would be the damage culprit. Asphalt is essentially a liquid, and the shoulder is necessary to keep the road shoved together.
~VOW

The terminal velocity of raindrops is ~30-35 mph. It doesn’t take a 4000 foot drop to reach that. Water squirted out of a hose as plenty of erosive power.

Well, huh. Google, “irrigation spray damage asphalt road surface”.

http://www.geocheminc.com/percol2.htm

http://www.apao.org/design3.shtml

Sounds to me like water flow is water flow, no matter whether it comes from irrigation sprays or from the sky.

When water seeps under the asphalt at the side of the road or through cracks in the surface it softens the ground underneath. Then as traffic goes over the road the soil supporting the asphalt is “pumped” out from under by the traffic load. The surface then sags and breaks up leading to potholes.

One more time. It isn’t the road surface that suports the load. It is the ground under the surface that does that. The surface is mainly there to keep the ground dry and in the same load-bearing condition it was when the road of first put down.