Rain water runoff rutting and destryoing dirt bridge

[progulf7]

Not an engineer here but have a small ranch"ette" in central texas with a sloped road leading to a dirt bridge....long storey short, we have an 8 ft circ. culvert covered with dirt and slag rock over the top put in by a logging company. When the rains came down the hill, it rutted the dirt road and washed out the entire right side of the bridge. Before we go to rebuilding the bridge and hauling in dirt to replace the 4 foot deep ruts, I want to find some suggestions on how to prevent this or divert the water away from the road and bridge.

Any suggestions are greatly appreciated!

 

[beej67]

I assume the hill is to the right of the road, and water first runs down the hill, then follows the road embankment a ways to the culvert, and in following the embankment a ways, it cuts out this rut?

If so, the rutting problem is a combination of flow rate and flow velocity, the flow rate comes from the watershed, and the flow velocity comes from the flow rate and the "channel" slope - in your case the longitudinal slope of the rut.

Honestly, you need to have an engineer look at it. Your engineer will need enough topographic data to estimate the watershed intercepted by the road, and will use that watershed delineation, the land cover, and some location specific climate data to estimate the flows that are causing the rut. Without knowing the magnitude of those flows, and knowing the slope of the road, you can't know what kind of solution you need.

This is a fairly simple thing to calculate for someone who knows what they're doing. Just about any civil guy here could do it for you, with the right information.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[cvg]

graded berms or ditches can be used to re-direct the flow away from the bridge abutment. Rock riprap laid over filter fabric can be used to reduce erosion. A culvert could be used to pass the water under the road before getting to the bridge. Any more advice will require more details from you.