Help with trail hill constantly washing out

[oosik]

I think ArlyA has the best answer. Talk to a local contractor and seek their advice. You need some pretty aggressive corrective measure with that much flowing water.

Whatever - you need to keep that water from flowing right down the center of the road. Rip-rap lined ditches, catchment basins, culverts, etc. I hope the road, in its current location, is important.

 

[papa4fofox]

Take a look at https://woodlandinfo.org/files/2018/10/NA-TP-06-98.pdf for some ideas.

 

[Egon]

From the pictures that are shown no advice can really be given.

look at a contour plan showing the drainage area to get an idea of volume and ways the stream could be directed or diverted.

 

[jfh0jfh]

I had two oil-company roads that washed like this.

I made new pathways with better grade.

I cut diversions across the bad roads, filled with stumps and organic matter; then good dirt; then seeded w/ fescue.

IME roads that keep washing tell you to relocate them.

 

[pacosperson]

Stop using your roads as drainage ditches. Not everyone with a backhoe is a Civil Engineer. I've been through this. The problem will not go away until YOU find a way to reroute the water and make it go UNDER your road.
Drive around your community. You'll probably find the highway dept. uses THREE FOOT culverts to move water UNDER roadbeds. You probably don't need three foot. I got away with 14" plastic pipe. BUT until I ran the water UNDER the road, the problem continued.
Good luck.

 

[SnagDump]

It appears that your road is below adjacent ground level and judging by the pic it also goes directly down the fall line of the hill. Is this correct? Fall line roads/trails are notoriously difficult to drain since there is no cross slope - no way to effectively inslope or outslope to get water to drain off continously.

A) Your most economical shot is to build waterbars or rolling dips at intervals and for sure get one just above where the gulley starts. Getting the waterbar or dip to drain if there's no cross slope will be the problem - you may have to ditch it out a long way. A skewed waterbar or dip will work best - not straight across.

B) An alternative is to sharply slope the road/trail surface to one side or the other, build a ditch there and then armor the ditch with rock. At some point you'll have to get that ditch to drain and the longer the undrained run the larger the rock you'll need.

C) The real fix, and the most expensive is to add fill - either dirt or pit-run rock to the road enough to bring it up above the adjacent ground level and then slope it to one side or the other or crown it so it drains continuously.

On an unsurfaced road/trail (no gravel) any ruts left from travel during wet periods will defeat your drainage scheme. Waterbars made of gravel or base rock that won't rut will help with that.

 

[John_Mc]

First suggestion: get your kid out of the gully. I have no idea how stable the soil is, but why take the chance. If that were a worksite, all sorts of safety precautions would be taken before allowing someone into a ditch up to their chest.

Second: the main key to building reliable trails is laying them out properly in the first place. You are going to be waging a nonstop battle keeping that trail passable. Relocate itand look to keep a grade of less than 7% if at all possible, avoid the bottom of a "bowl", and add water bars or broad-based dips to redirect the water off of the trail.

 

[VroomVroom]

Where the water starts running just before it starts cutting grooves, slant road to one side with good ditch so water wants off the road as it lands. No time to run down the road

 

[CobyRupert]

Grade it so that water runs off the road (example: in ditches), not in the road.

 

[DJ54]

Depending on how much room you have to work with, you could also totally revamp your road, and build switchbacks, (yeah, not going tp be cheap) zig-zagging down the hill to soften the grade, plus use some of the great idea above, keeping grade between 7%-14%, and water bars to get water off the road.

Our horse club does a lot of trail maintenance, and reconstructing older bridle/multipurpose trails in State Forests, and Parks. One Forest in particular is weathered off sandrock, and basically 4' - 6' of loose fine sand, and trails traverse down 1.5:1 slopes. In these spots is where we put in the switch backs, with multiple water bars. Most generally, they hold up well in normal years. But, wet years, and people not having sense enough to stay off of them when it's muddy can cause a lot of maintenance issues.

In the really nasty spots,where it's a springy clay sand, we'll lay drainage pipe, then hardsurface with geotech,#4 limestone, then top dress with finer limestone. But of course that is normally paid for with grants we secure for funding. A little different when it's coming out of your pocket.

Here, Sept is the perfect time to seed such area's. Sowing something deep rooted is best, something like Cereal Rye which if sown right before a rain will be sprouting in as little as 3 days, and mix with a deep rooted type grass/Legume. Cereal Rye is winter hardy, and will survive through the winter, head out in early summer, and reseed itself somewhat, while the other grass(es)/Legumes get established, and eventually choke out the Rye. Your local Soil and Water Conservation should be able to suggest a plan,and cover crop to suit your needs. It's a free service, you pay for with your taxes. Might as well take advantage of it.