Seeking Advice about Soil Erosion Control

[dinga]

We have a small block in Rayong Province (a neglected orchard where we are presently building a small house).

 

Our block is on a slope - with erosion being a problem/challenge due to water runoff occurring in 2 directions.   Any suggestions about where we can get some advice about the best counter-measures (we have planted some vertiver grass but that seems to only offer a very limited, partial solution, along with what are variously known as whoa-boys/water bars/cross banks/humps/diversion banks [which resemble speed bumps] along the access track). 

 

Am thinking we really need to get someone knowledgeable to undertake a site inspection.  The Tessabaan hasn't provided any suggestions - worth noting that the run-off goes into a small creek that runs along some land that is owned by the Government and which abuts our block (hopefully that may be useful in getting some interest from a government authority).

 

Thanks!

[OneMoreFarang]

Talk to a professional construction engineer. They have formulas for these kind of situations. 

[carlyai]

Have a look at information on Textile Matting. I think that's what it's called. 

My son said they use it extensively on road drainage construction in Australia. 

He is building a B&B on a hill top and where he has installed the textile matting under the access dirt and gravel road it hasn't eroded, but where non installed, the top level of road base has washed away. 

He's also built some small dams using it and this orange colored like putty stuff (can't remember the name, but they use it in Thailand in bores).

[Crossy]

Yeah, geotextile and possibly diversion channels to at least direct your runoff is the way to go.

 

You definitely need to engage a professional, he may not be cheap ???? 

 

[sometimewoodworker]

The main university agricultural department are the people to ask, if you have a large university, then it’s very likely that the agricultural professors will have a side business in providing the kind of work that you want as training for their students. Also the army provides training to its conscripts on those subjects, so see if you can find out if they can help.

[Nino3]

1 hour ago, Crossy said:

Yeah, geotextile and possibly diversion channels to at least direct your runoff is the way to go.

 

You definitely need to engage a professional, he may not be cheap ???? 

 

I agree. If the slope is eroding then it is best to address firstly at the point where there is any directed waters. Diversion at the top of slope is key.

 

Secondly, address the slope itself to protects from direct rainfall. Textile/stabilization works well on slopes to a certain degree. Depending on grade of angle. Myself, do not install on a slope any steeper than a 2:1.

 

Problem with textile material, at least in my experience, is that they are black. This has proven to be an issue as the material gets so hot while in the stages of trying to grow vegetation that the heat kills off the vegetation.

 

Cement soil stabilization also works well. There are also polymer products that work well but availability here is unknown.

 

Depending on slope size and availability of stone in your immediate area, it may simply be best to hard armor, install large stone on the slope. I say this as labor is far less expensive than paying an engineer and buying costly materials or services.

 

Many years ago I seen a slope stabilization product installed in Pattaya that I had never seen in my country. It was a textile material, accordian type, 3" deep pockets, that was pinned to the slope then filled with material, small stone or grass. I found the product in my country and utilized it on a project with excellent results.

 

I was just in Pattaya, passed by the area and the slope is still in tact. Whether or not the slope has been reworked I could not say.

 

And yes, I would agree that a soil stabilization expert here may be expensive.

[Muhendis]

Before my house was built, it was nothing more than a 1 Rai x 1 metre high island of soil. I had a truck wide slope adjacent to one corner which went to the original land level. I guess the slope must have been about 15º. After the next rainy season when I saw it again the slope had developed some water channels and was eroding. 

My fix was a large lorry full of mixed aggregate which we spread over the slope filling canals and making a decent looking gravel road. We smoothed it a bit by driving my car backwards an forwards on it.

That was about 11 years or so ago. The stones are still there but invisible below a layer, added by nature, of soil and grass which took about a year or so to develop.

It's a totally non-professional approach but it works.

[sometimewoodworker]

2 minutes ago, Muhendis said:

My fix was a large lorry full of mixed aggregate which we spread over the slope filling canals and making a decent looking gravel road. We smoothed it a bit by driving my car backwards an forwards on it.

That was about 11 years or so ago. The stones are still there but invisible below a layer, added by nature, of soil and grass which took about a year or so to develop.

It's a totally non-professional approach but it works.

That works, if you add a layer of blue plastic or shade cloth before adding the stone it will red the soil that will migrate upwards.

[ozimoron]

Small rock dams at regular intervals along the drainage channels to slow water flow. If the rocks are very small, encase them in chicken wire to form blocks.

[Muhendis]

16 minutes ago, sometimewoodworker said:

That works, if you add a layer of blue plastic or shade cloth before adding the stone it will red the soil that will migrate upwards.

Good thinking but I didn't do that and it still works.

Do you think the infrequent use may be the reason why it works without plastic or shade cloth (whatever that is)?

[Muhendis]

9 hours ago, dinga said:

Our block is on a slope - with erosion being a problem/challenge due to water runoff occurring in 2 directions.

A bit like this?

Perhaps you could adopt something similar.

[Encid]

9 hours ago, dinga said:

we have planted some vertiver grass but that seems to only offer a very limited, partial solution

Vetiver grass needs a Nitrogen rich fertilizer (such as chicken poo - available at every Global House) at time of planting, and again at regular monthly intervals during the growing season (which it currently isn't) and a good supply of water until the seedings have become established.

 

We we fortunate enough to have planted our 2 metre high slopes with vetiver seedlings (at 150mm centres in rows 1.5 metres apart - as recommended by HRH Rama 9) and we had an exceptionally wet rainy season this year, which meant that our grass established itself very quickly.

 

Now, we have no erosion at all. 

 

[sometimewoodworker]

43 minutes ago, Muhendis said:

Good thinking but I didn't do that and it still works.

Do you think the infrequent use may be the reason why it works without plastic or shade cloth (whatever that is)?

I can’t comment on that, all can say is that this is March 2017 about 1 year after laying it

and this is today 

 

so the plastic makes a big difference.

[GreasyFingers]

46 minutes ago, Muhendis said:

A bit like this?

Perhaps you could adopt something similar.

 

Thats not a slope, its a cliff.

[Pogust]

You need a permaculture designer. If you contact me directly I might be able to help. I'm in Rayong area.

 

[dinga]

On 1/5/2023 at 5:32 PM, Encid said:

Vetiver grass needs a Nitrogen rich fertilizer (such as chicken poo - available at every Global House) at time of planting, and again at regular monthly intervals during the growing season (which it currently isn't) and a good supply of water until the seedings have become established.

 

We we fortunate enough to have planted our 2 metre high slopes with vetiver seedlings (at 150mm centres in rows 1.5 metres apart - as recommended by HRH Rama 9) and we had an exceptionally wet rainy season this year, which meant that our grass established itself very quickly.

 

Now, we have no erosion at all. 

 

You are correct... after a bit of research it seems that you should trim the grass to 30cm above ground level initially after 4 months of planting.

The second cutting should be done just before flowering starts in the second year.

After that you can just leave it to grow, unless you plan on harvesting the whole plant for the essential oils found in the root legumes.

 

We are not planning to harvest as we want the erosion prevention measures provided by the root systems.

Expand  

Excellent - thanks (have just trimmed the grass as outlined elsewhere in another thread).  Wish I knew at planting time (some 6 months ago) that the vertiver should be initially fertilized with chicken poop.  Should I fertilize now or is it better to wait until just before the Wet Season (say May)????  Any tips/traps as chook poo is pretty strong???

[Encid]

23 hours ago, dinga said:

Should I fertilize now or is it better to wait until just before the Wet Season (say May)????  Any tips/traps as chook poo is pretty strong???

There is no harm in fertilizing it now... it will just break down into the soil.

The grass will start to grow again soon... as soon as this cold spell is finished and night time temperatures climb.

The plants tend to go into a dormant phase when the temperature drops below 20 degrees at night.

 

We buy our chicken poo in pellet form in large bags at Global House.

Just 1 handful per plant is sufficient to last 30 days before the next application.

6 months of good feeding and watering will ensure that you have good healthy plants that will then be pretty self-sufficient with strong deep roots.