How to fix mountain washout

[bdhsfz6]

I fixed a similar situation with used railroad ties and built something like this:

If there is a rail line being torn out in your area, you can usually get them cheap, sometimes even for free.

You could also buy treated 6X6's as well.

 

[LouNY]

It will take a muti tiered wall starting further down the and stepping its self up,
More rocks less dirt.
One other option will be drop some trees, limb them and lay the logs against other trees.
Backfill and add another log or two, and again step your way up.
You can even use your trimmings in the backfill.

 

[MACflyer]

Thats plenty for digging drainage ditches, waterbars, etc.

Probably the way my brain would work to armor your eroding section is with some BIG rocks, boulders, concrete chunks, etc. Dig enough of a pocket into the downslope into native soils to retain them firmly, then pack it all up with rocks so heavy that some rain wash can't budge them, and gives a nice big footprint for widening the trail atop. But again, first focusing on making sure water doesn't go off the trail in that spot.

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.

 

[MACflyer]

I'm curious how your road was carved out of those boulders on your mountainside in the first place. That's pretty impressive.

It looks to me as if water picks up a lot of velocity coming off the top of the mountain before it arrives at your road where it then starts looking for the low point to continue running down the mountain. Over the long term, water always seeks the path of least resistance. So it hits your road, probably runs down it a bit, and then has started eroding this one particular spot.

The reason the fill failed is because all that wet dirt pushed against the fence posts like 5' long levers that could be only anchored maybe a foot in the ground. This is like trying to build a retaining wall...too much force being exerted against the top of the wall caused it to fail.

If you compare this washout to the other land nearby, the washout is a vertical drop off unlike the section adjacent to it that is more gradual and banked with trees that support the road.

One of the challenges with trying to build up the eroded section is that fill material will want to roll off the mountain.

Not saying this is the way to stop the erosion, but first step would be to try to divert the water somewhere it doesn't continue to wash this soft area away. Then you need to find a way to create an anchor point to lock your fill in place.

Also not sure, but possibly road bed mat could be helpful. Possibly some railroad ties. Not saying these are the answers just yet, but you need something substantial and yet manageable to hold the fill material.

Rocks mortared together with cement to form a solid and sloped rip rap are another possible option if you can establish an anchor point as a base to keep the rocks from sliding off the mountain. Or just add rip rap rock in series of dumps over time without cement if you can figure out how to keep it from sliding.

Seems like a choice between building a very solid vertical retaining wall w/drainage versus trying to add a lot of rip rap over time to the slope?

View attachment 3682411

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.

 

[Jrasband]

Build a gabion cage. You can use hog panels, cut them in half length wise for the top and bottom, use full height for the sides. Make stays with wire placed every 2 ft. horizontal and vertical to prevent the cages from being spread open with the rocks.

 

[Topzide]

As above, you could also stack Sakrete bags and put a T post through them to keep them anchored. Punch other holes in bags to allow moisture to cure them. Have seen them used to make poor man's boat ramp!

 

[Jrasband]

As above, you could also stack Sakrete bags and put a T post through them to keep them anchored. Punch other holes in bags to allow moisture to cure them. Have seen them used to make poor man's boat ramp!

I think a gabion cage would be much more effective and have less chance for failure.

I mentioned horizontal and vertical above, I realized this is misleading. I meant all wire stays are horizontal(go from side to side) every 2 ft. The wire stays are started about 2' from the bottom of the cage and around 2' from each end. Do another row of wire stays about 2' above that. Build the cages in place, put Geotextile fabric below and on uphill side and you can make them a full 16' long if desired. If you want it longer you just cut more panel and add on.


I bought one of these which makes quick work of building the cages.
Amazon.com

You can also use a wire and twist it by hand just takes a lot longer.

 

[newbury]

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?

 

[MACflyer]

I think a gabion cage would be much more effective and have less chance for failure.

I mentioned horizontal and vertical above, I realized this is misleading. I meant all wire stays are horizontal(go from side to side) every 2 ft. The wire stays are started about 2' from the bottom of the cage and around 2' from each end. Do another row of wire stays about 2' above that. Build the cages in place, put Geotextile fabric below and on uphill side and you can make them a full 16' long if desired. If you want it longer you just cut more panel and add on.


I bought one of these which makes quick work of building the cages.
Amazon.com

You can also use a wire and twist it by hand just takes a lot longer.

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.

 

[MACflyer]

I fixed a similar situation with used railroad ties and built something like this:

View attachment 3682588

If there is a rail line being torn out in your area, you can usually get them cheap, sometimes even for free.

You could also buy treated 6X6's as well.

The 6x6 fence posts I have in place would work well for this, I think it's the way to go.