How to fix mountain washout

[MACflyer]

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

I think I'd need a Chinook to sling them in. The pictures really don't do it justice, it's dangerously steep in many areas.

 

[2manyrocks]

A project like this requires thinking about what you can physically manage. Handling large rock or RR ties without a good sized excavator may not be workable. Next best option, IMO, is smaller rock, but cemented together or perhaps held in place with the gabion structures previously suggested that don't involve having to mix cement. I haven't worked with them myself, but perhaps they would work?

 

[MACflyer]

Lots of good ideas in here. The trail continues about 100 yards beyond this washout, and then there's a switchback and it continues up. I installed water bars on the above portion to try to prevent any more water flowing down to this one section. I agree with one comment that cutting further into the mountain would be preferable, but not feasible with my equipment or budget. I think the gabion might be the best solution, I just need to figure out how to install it. Using equipment isn't feasible, it's just too narrow on the trail and too steep on the downslope. The slope is steep enough that I am scrabbling on all 4s if I try to go up or down it at all, without trees to grab I wouldn't be able to climb back up it. Swinging a tool will require some type of support. I'm thinking I might tie myself off to the UTV and cut in a base by hand.

 

[2manyrocks]

I hadn't looked at your latest pictures in post #26 until just now. That's too steep and narrow to safely operate your backhoe. Even working by hand on the downhill slope would seem to require a body harness so you can rope off to something secure. My preference would be something fixed like a tree uphill of the work area instead of anything that could potentially roll.

 

[pacosperson]

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?

I looks pretty rocky. The truth is the problem will continue until you stop using that ‘trail’ as a drainage ditch. I had a similar problem and fought it in every way until I read US Forestry Service road maintenance instructions. Every public road you have ever driven on has had drainage along the sides and pipes running UNDER the roadbed. Water is never diverted onto the road bed. An incredible amount of water is going down that slope during a thunder storm. As soon as water finds a way across the roadbed it will erode it at an accelerated pace. I had several 4” PVC pipes feeding into ‘catch basins’ that had 14” pipes passing the water under my driveway. And those 14” pipes were barely enough to handle the flow.

You may not be willing to go to that expense. In my case it was a driveway, not a trail. I see what looks like the top of the trail. Maybe start there with a ‘homemade’ catch basin of football size rocks feeding a 4” pipe under the trail. See how it works and learn how many more will be needed. Old, discarded, yard sale, scrapyard gas grill grates make good screens to prevent most clogging. Good luck.

 

[JRH02]

We live on the north facing side of a deep and mostly steep sided canyon. It's a pretty arid climate for 3/4 of the year but our worst time is in the winter with snow accumulation and then a warm hit with maybe a rain-on-snow event to multiply the severity. Water bars, laterals - whatever you want to call them are our best and only workable solution. And it's an ancient logging road with imbedded large stone and boulders++ that you do NOT want to remove. There are a bunch of laterals and a pain to maintain and drive over. There's no reasonable way or room to build a ditch on the uphill side. Certainly no use for culverts. So it's really all about having enough laterals that there is the least amount of water flowing in any one spot. For drivability they are never perpendicular to the trail.

 

[redman135]

I went through all 5 pages. In the first 2 pages is what you need to do.
The water bars on the top section to keep water off the trail to start with are a good start.
To repair the washout you need to install a water bar just above the washout to prevent your work being undone. I recommend you aims the waterbar flow onto tree roots to prevent a new point of scouring.
Actual repair: Can you get a "zero swing" digger up there? Something in the 6-10 ton size to have the reach and weight. If not you have some hand digging to do.(pick, shovel, and mattock, literaly.)

Suggest you make a flat floor and use gabion wall. Do job in "lifts" (layer of fill) and at each lift extend the lift further into the trail. This is called "keying in" for long term stability.
NOTE you must bring the repair up to enough above the trail level to prevent water running over the repair.
You may have to reshape the trail camber to stop water running to the repair point and wrecking the job if the water bar just above the repair does not work.
Also I recommend you put a drain on the inside of the trail and at a point below the wash put install a culvert, where the water can not create a new scour out.
I have a steep track like yours (metaled)and is 30 degrees (measured), at the steepest part. Average grade is in the 15 - 20 deg range.The waterbars are 30 - 40 yards apart, with a drain on the high side and culverts as required.
This is what is reqired to keep my track in good condition as it provides acess to 1/2 my farm.

 

[old and tired]

I don't have photos but can get them later this week...

Only posting since I said I was going to post a photo...

Like most photos, hard to tell steepness, height and the slope.

These 6 foot "T" posts are driven in the side slope and backed filled with wood sideways and rocks. They were in a straighter line but the middle ones have been push down hill.

It's about 10 feet of fill, it really hasn't been touched in years. There was a 4" lip at the top that directed water past the pine tree downhill or water was directed off the slope *before* this filled area.

My guess is the OP will be dealing with lots more rock and may not be able to pound in "T" posts as far as they should.

I would still try and pack down the dirt that slid down, insert rods or posts (lots of them) and build up the side slope.

Build a dam at the top to keep water off this area. I did ditch the inside of the road to divert water downhill instead of across the road.

 

[JRH02]

How critical is this 'trail'? When y'all are out roaming the woods are crocks your normal footwear?

My guess is the OP will be dealing with lots more rock and may not be able to pound in "T" posts as far as they should.

My T-Post driver is called the 'Rock Finder'.

 

[MACflyer]

I went through all 5 pages. In the first 2 pages is what you need to do.
The water bars on the top section to keep water off the trail to start with are a good start.
To repair the washout you need to install a water bar just above the washout to prevent your work being undone. I recommend you aims the waterbar flow onto tree roots to prevent a new point of scouring.
Actual repair: Can you get a "zero swing" digger up there? Something in the 6-10 ton size to have the reach and weight. If not you have some hand digging to do.(pick, shovel, and mattock, literaly.)

Suggest you make a flat floor and use gabion wall. Do job in "lifts" (layer of fill) and at each lift extend the lift further into the trail. This is called "keying in" for long term stability.
NOTE you must bring the repair up to enough above the trail level to prevent water running over the repair.
You may have to reshape the trail camber to stop water running to the repair point and wrecking the job if the water bar just above the repair does not work.
Also I recommend you put a drain on the inside of the trail and at a point below the wash put install a culvert, where the water can not create a new scour out.
I have a steep track like yours (metaled)and is 30 degrees (measured), at the steepest part. Average grade is in the 15 - 20 deg range.The waterbars are 30 - 40 yards apart, with a drain on the high side and culverts as required.
This is what is reqired to keep my track in good condition as it provides acess to 1/2 my farm.

This is essentially what I’m planning. The water bars are completed, but unfortunately I will be doing lots of hand digging while tied off, then the gabion. Will be a couple weeks before I am able to get back to it.