How to fix mountain washout

[Jrasband]

I've got about 400 feet of bank that needs stabilizing and was thinking of using gabions.
May I ask why you went with hog ring versus Gabion Spirals Binders (helicals) for attaching?

I did not even look into the gabion spirals. It looks like it may be a little more expensive but not having to buy the hog ring gun would offset that.

 

[newbury]

I did not even look into the gabion spirals. It looks like it may be a little more expensive but not having to buy the hog ring gun would offset that.

I'm wondering about the difficulty of twirling the spiral on versus manually using a plier type clamper. What gauge rings do you normally use?

 

[Jrasband]

I'm wondering about the difficulty of twirling the spiral on versus manually using a plier type clamper. What gauge rings do you normally use?

Those spirals go on pretty swiftly. I have used them before for connecting cattle panels for livestock fencing. The Hog rings go on real quick too, once you get the hang of using the tool. You have to kneel down to put the c rings on the lower areas of the cage.

One thought I just had... if you are building the cages in place and have excavated the soil to build a level pad for the cages, the spirals might be difficult to install. For instance, the spiral on the bottom of the cage connecting it to the sides.

11 gauge hog rings is what I used, 1 on every square (so one every 4 inches).

 

[deezler]

Never heard of a gabion cage. Looked it up and I'm familiar, just never knew the name. Similar to hesco barriers we used overseas.

There's about a 100-150' drop-off before I'd be anywhere close to a spot where I could put one in. I like the idea, but not sure how I'd implement it with such a long and steep drop.

Nah nah nah. Back up there with your backhoe, and scoop out a flat bottom hole in the native soil underneath this problem area, then you could drop in a cage and fill it up. If you get back down to the native soil on the trailside, it should have plenty of bearing capacity and stability.

 

[Jrasband]

Yeah, the grade does not look so steep that you can't make a 2' flat spot below the trail/road.

 

[MACflyer]

Nah nah nah. Back up there with your backhoe, and scoop out a flat bottom hole in the native soil underneath this problem area, then you could drop in a cage and fill it up. If you get back down to the native soil on the trailside, it should have plenty of bearing capacity and stability.

I think if I had a much larger machine, that would be the best solution. I just went sliding down the embankment to try to better capture it. The trail is too narrow to have my tractor perpendicular, but even being too close to the edge to have an outrigger down I can't reach any native soil. The dirt the bucket is near is just loose fill from the failed initial bulwark.

 

[airbiscuit]

When I went elk hunting in Washington state, I was impressed with their mountain roads. the roads were canted into the side of the mountain, and they had water bars (basically speed bumps at a diagonal) also angled into the side of the mountain, and a shallow, rock filled ditch on the inside edge of the road. Every so often there would be a culvert to discharge the water off to the side,

It was counterintuitive to me that they directed the water inward, but it worked. There is lots of information on the Internet about building mountain roads. In any case, I think you need redirect the flow of water at that location.

 

[airbiscuit]

I started digging water bars. Unfortunately I think I would need a full sized excavator in order to dig a pocket like that. It's just too narrow and steep.

The water bars I saw, were raised above the roadbed (like a speed bump) not a depression.

 

[deezler]

I think if I had a much larger machine, that would be the best solution. I just went sliding down the embankment to try to better capture it. The trail is too narrow to have my tractor perpendicular, but even being too close to the edge to have an outrigger down I can't reach any native soil. The dirt the bucket is near is just loose fill from the failed initial bulwark.

Ok those pics are helpful, definitely very steep and a narrow trail already. My intuition would be to excavate lightly on the outside edge of where you already have substantial trail width loss and build back up with boulders or gabion cages, etc. Then you'll be driving over top of this repaired area. Its more of a anchor for the main trail bed than a wall to build outside the dirt trail bed.

 

[John_Mc]

The water bars I saw, were raised above the roadbed (like a speed bump) not a depression.

Around here, they are both: dig out the water bar, and pile it up on the downhill side.

 

[Topzide]

Another thing to use to keep water off the trail. Get some used guard rail and lay in trail at angle to catch and shed water off trail. You can use to bolt holes to help anchor it in place. Have seen it used on a few hills with great success! If set right, you can push snow over them without catching them. Just another idea to throw out there.
With how far you can reach, might you be able to anchor in a cage to hold?

 

[LouNY]

You will need a larger backhoe excavator with more reach. That is the problem with the little ones they don't have much reach.
Reach out n down trench in and flat or even a bit of slope into the mountain and the mentioned gabion cages.
Even if you start out short and narrow then step it up a bit taller and wider and stair step up to or a bit above your desired level.

 

[airbiscuit]

The previous owner told me a guy with a small dozer was able to cut the trail in. I was also amazed because I'm not sure how he got a dozer through many of these rock sections. I've started on the water bars now, I like the bed mat idea as well.

Just toss in some rocks the same size as the cajones on that (small) dozer operator who cut that trail in.

 

[Jrasband]

Still doesn't look that steep to me that you can't make a flat spot to put a cage in. It seems you can get your tractor closer to the uphill side so you can get your outrigger down. Also, You don't even need to use your tractor to make a flat spot, if it is not rocky there it won't take you long to make a flat spot with a mattock.

 

[terraformer]

Move your trail around that area. Mother nature is going to do what it is going to do.

 

[EddieWalker]

If it was my place, I would stack sacks of concrete to build up a wall to support the trail. While the sacks are still dry, pound rebar through them to lock them all together. Also pound the rebar into the soil that the sacks are sitting on. Bigger rebar into the soil would be better.

Here is an example of what I did for a culvert for my pond. I've seen the same thing done on a lot bigger scale.

After building it up, I would fill behind the sacks with gravel so water can drain easier and not build up behind the sacks.

 

[miscjames]

Depending on how good you are with a chain saw… start dropping trees along that edge drag them in place with tractor. The longer /more the better. Stack them up like cord wood. Until that side is higher then mountain side then fill with dirt and rocks and get some vegetation growing on it. Then ditch the other side so the water runs past that point. And water bar along the trail. Start kind like this.

 

[panamaguy]

I've got a trail that runs up the side of my mountain. It's badly eroded in one spot, I wanted to fill it in before it makes the trail impassable. It's washed out on the downslope side, and it's extremely steep. Not sure if I'd even be able to get up it on foot. View attachment 3682140

Initially I drove 4 metal t posts into the side of the mountain, parallel to the trail. I had some 6x6 fence posts from a fence I'd taken down, so I laid them down against the t posts. Then filled the whole thing in with dirt.
View attachment 3682141
View attachment 3682142
(The one t post at a wonky angle was too bent to drive in properly, but it's too steep to get down and pull it back out so I just left it. Not really doing anything to support the posts)
View attachment 3682143
It looked great for about 4 days, when a heavy thunderstorm rolled through and the t posts failed. View attachment 3682144

My next attempt I'm thinking of increasing the amount of t posts, and then using rocks to fill in the bulk of the space with dirt added as a filler. The thinking is less diet to hold water means less weight for the bulwark to support. Does anyone have any better ideas or suggestions on how to build this before I go rappelling down the mountain to get the posts that washed out?

Your never going to change nature. If the water has decided thats were its going to flow, thats were it will flow.. Stop it there and it will find somewhere else to flow and wash that area out. If you just use it as a hiking trail build a small bridge over the washout

 

[fishhead]

Mountain roads typically are cut into hillsides, not on fill placed on the down slope- this is a much more stable approach long term. Not sure where you are in WV (wet virginia) but i know in the North it was largely sandstone. The right way to do that section is take out some of the rock above either with explosives or a jack hammer on a small excavator- won't be cheap but it will work- too because the up slope adjacent to the road will be rock you won't have to slope it and will thus not need to remove a huge amount.
Then you need to a bunch of grade reversals and mix of insole and out slope drainage so you are having to maintain stuff constantly

 

[2manyrocks]

I think that this washout can still be solved by careful installation of something like the railroad tie retaining wall previously suggested that incorporates tiebacks to keep it from topping over.

The OP knows the actual terrain, and if he is uncomfortable using his backhoe due to the dropoff and limited space, I respect his assessment. Doing much digging could loosen the soil and cause the washout to worsen.

If it is going to wash because that is the lowest point and the water can't feasibly be redirected, I would want it to wash over rock or concrete that allows the water to flow over it without washing away.

Many trails have 6x6 ties that were placed only because someone hacked out a place for them with a mattock.

Dealing with this washout may involve quit a bit of physical labor because it is inaccessible to machinery or unsafe to operate machinery on the slope involved. But consider the effort of trying to relocate a trail like this because one section was allowed to wash out.