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What to do with large sloped hillside?  RSS feed

 
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I have a large area of land with pretty steep slope, ranging from 20-40 degrees. I hope to plant rows of shrubs onto that area. My problem is how to get access to all the areas to plant as well as to water. The area is very arid, only 8 inches of rain per year.

This is the pic: https://s9.postimg.cc/5zumjwlgf/slope.jpg


Walkway and railing for safe passage is definitely needed.

Any ideas of what I could do with this land. It is such a waste to leave it empty like this.
 
pollinator
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1.  Swales.  A hillside like that could handle upwards of 4 or 5 swales to capture water.  After you've dug your swales, then you'll plant your trees below the swale.  The water captured by the swale will slowly percolate down to the root zone of the tree below.

2.  Somehow, you're going to need to find a way to get some additional water up onto that slope.  Even if it's a matter of capturing grey water and then pumping it up to a tank at the top so that you can use gravity to trickle that water down to the trees as needed, you need to look into options for smart irrigation.  Is there a way to capture run-off from the parking lot at the base of the picture?  It looks like there is a very green tree growing in that location because it's probably getting a lot of runoff water.  A simple pond to capture water diverted from that asphalt lot could capture thousands of gallons of water after a small rain storm.  One inch of rain falling on 1 acre of ground is equal to about 27,154 gallons.  Can you imagine having a 20,000 gallon tank at the top of that hill, with a pump to fill it every time you get a rainstorm?

3.  Can you tell us which way the hillside is facing?  If you are standing at the top of the hill looking downward (directly down toward where the picture was taken), what direction would that be?  This is important because a south-facing hill is a giant heat sink.  For every 5 degrees of slope (on a south facing hill), it's the equivalent of being 150 miles closer to the equator.  In other words, a 25 degree slope on a south facing hillside is like living somewhere 750 miles further south.  It's crazy how much hotter a south facing slope can be.  Thus . . .

4.  You need to find a way to provide some shade on the south/south-west side of your growing trees.  If you can pile up biomass on the south side of your trees, you'll keep that soil from getting scorched by the sun and completely drying out.  I have a south facing hillside with about 20 trees on it, and I take all the branches and vines and such that I don't want to put into the compost pile and pile them up below (on the south side) my trees.  If you pull that mulch/biomass back, the soil below is cool and moist.  It makes a huge difference in water retention and soil life.

5.  Look into this technology: water boxes.

https://www.groasis.com/en

The technology is simple, but it exponentially increases the survival rate of trees.

Best of luck.
 
Nh Ng
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Marco Banks wrote:1.  Swales.  A hillside like that could handle upwards of 4 or 5 swales to capture water.  After you've dug your swales, then you'll plant your trees below the swale.  The water captured by the swale will slowly percolate down to the root zone of the tree below.

2.  Somehow, you're going to need to find a way to get some additional water up onto that slope.  Even if it's a matter of capturing grey water and then pumping it up to a tank at the top so that you can use gravity to trickle that water down to the trees as needed, you need to look into options for smart irrigation.  Is there a way to capture run-off from the parking lot at the base of the picture?  It looks like there is a very green tree growing in that location because it's probably getting a lot of runoff water.  A simple pond to capture water diverted from that asphalt lot could capture thousands of gallons of water after a small rain storm.  One inch of rain falling on 1 acre of ground is equal to about 27,154 gallons.  Can you imagine having a 20,000 gallon tank at the top of that hill, with a pump to fill it every time you get a rainstorm?

3.  Can you tell us which way the hillside is facing?  If you are standing at the top of the hill looking downward (directly down toward where the picture was taken), what direction would that be?  This is important because a south-facing hill is a giant heat sink.  For every 5 degrees of slope (on a south facing hill), it's the equivalent of being 150 miles closer to the equator.  In other words, a 25 degree slope on a south facing hillside is like living somewhere 750 miles further south.  It's crazy how much hotter a south facing slope can be.  Thus . . .

4.  You need to find a way to provide some shade on the south/south-west side of your growing trees.  If you can pile up biomass on the south side of your trees, you'll keep that soil from getting scorched by the sun and completely drying out.  I have a south facing hillside with about 20 trees on it, and I take all the branches and vines and such that I don't want to put into the compost pile and pile them up below (on the south side) my trees.  If you pull that mulch/biomass back, the soil below is cool and moist.  It makes a huge difference in water retention and soil life.

5.  Look into this technology: water boxes.

https://www.groasis.com/en

The technology is simple, but it exponentially increases the survival rate of trees.

Best of luck.




Thank for the detail info. The slope is facing W/NW. It shapes more like an amphitheater.

My big problem is create safe access, stone path or dirt path so that I can get up there to tend for any plants.

I initially hope to do some terracing for plant bed but the county regulation require retaining wall and it will be too expensive. Not sure the regulation about swale. I have to ask around.

Now I only hope to plant directly on the slope and may be provide supplemental water in the summer.
 
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Even small swales can make a huge difference. I have one in my backyard that started a single shovel deep and wide.  It's had a very noticeable effect on the plants down slope. Even the tiny one, shallower than that and maybe three feet long, that I put next to my new fig tree seems to be helping.

Edit, hit submit before I was done... so to cont.

If your local codes prevent large earthworks, you could probably still do swales like my tiny one.  Every time you plant a tree, dig out a halfmoon trench upslope of the planting and use the excavated soil to build a berm just downslope of the rootball. This will create two small water catchments directly where the tree/shrub will most need them. It can also keep mulching materials where you put them, instead of washing away.

With planning companion plants will stabilize the berm, protect the tree roots from extreme temperatures, feed the soil, attract desirable insects, and/or provide more diverse yields. Place any rocks you dig up on top of the berms to help stabilize it while the companion plants get established.

To be honest, I haven't taken full advantage of my own opportunities here.  Other than the digging and mulch I just stuck the fig in the ground.  We are probably getting close to your rain levels so far this year due to the drought.  I am able to pour four to five gallons (buckets) of water directly in the root zone and trust it wont run off before soaking in.  I'll get a picture for you after the sun comes up.

 
pollinator
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I think that for slopes like the kind you're describing, Nh, terraces would be much better, and safer, and provide you with the access you need.

I would mark out the contour lines of your sloped hillside with stakes and line or ribbon, just so you can properly visualise it. I would use a plumb bob or a laser level to get the job done.

I would plan it out such that you are digging terraces out sufficient for at least the width of a pathway, with a swale on either side, and plantings downhill from that swale, such that your paths provide access and direct water into your swales.

I would, incidentally, plan to plant trees upslope of the paths, and shrubbery and shorter vegetation on the downslope side.

Whatever you do, it is crucial to make sure that you plant whatever grows well in your area, preferably something that forms a root mat to hold soil together and either accumulates nutrients or hosts nitrogen-fixing bacteria, but even if it just forms a dense root mat and produces biomass for chop-and-drop, you need it downslope of each swale, to curb the erosion that will occur, whatever you do, once you disturb the slope with shovels.

Swales are great tools in the permaculture toolbox, but they rarely provide access. Alone, they are much better suited to ground with a slope gentle enough to walk across without strain.

Good picture. Keep us posted, and good luck.

-CK
 
Nh Ng
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Chris Kott wrote:I think that for slopes like the kind you're describing, Nh, terraces would be much better, and safer, and provide you with the access you need.

I would mark out the contour lines of your sloped hillside with stakes and line or ribbon, just so you can properly visualise it. I would use a plumb bob or a laser level to get the job done.

I would plan it out such that you are digging terraces out sufficient for at least the width of a pathway, with a swale on either side, and plantings downhill from that swale, such that your paths provide access and direct water into your swales.

I would, incidentally, plan to plant trees upslope of the paths, and shrubbery and shorter vegetation on the downslope side.

Whatever you do, it is crucial to make sure that you plant whatever grows well in your area, preferably something that forms a root mat to hold soil together and either accumulates nutrients or hosts nitrogen-fixing bacteria, but even if it just forms a dense root mat and produces biomass for chop-and-drop, you need it downslope of each swale, to curb the erosion that will occur, whatever you do, once you disturb the slope with shovels.

Swales are great tools in the permaculture toolbox, but they rarely provide access. Alone, they are much better suited to ground with a slope gentle enough to walk across without strain.

Good picture. Keep us posted, and good luck.

-CK



How wide would you suggest a terrace should be ? I guess it has to be dug out by hand. Machinery may be difficult to get up the slope.
 
Chris Kott
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It is entirely dependent on what you want to move on your pathways, and how wide you wish to make your garden beds.

If, for instance, there's a wagon or cart that you would like to use for harvest, to haul soil, amendments, whatever, you want to make your pathways wide enough to accomodate it.

If you don't have access to the downhill-side garden bed from the terrace beneath it, it doesn't make sense to have a garden bed so wide you can't access it all. Likewise, you don't want a garden bed so wide on the uphill side that you can't access it from the path.

This model would have you making narrower terraces, but more of them, meaning that, overall, the volume of dirt you need to move to get the job done is lessened.

If you wanted wider terraces, I would suggest that you design keyhole-like pop-ins off of the path into the middle of the garden beds on either side, set at regular intervals, with perennials that don't require you to access them much and that perhaps don't require harvesting, such as nitrogen fixing shrubs and trees, planted in the out-of-reach areas of the beds. I would alternate these keyholes to either side of the paths, and from path to path.

What I would do is start taking measurements, top-down, and determine how much space you're dealing with, and mark out any natural terrace-like features, and see if you can work with them. Once you have everything measured out, you can look at different scenarios of wider or narrower terraces, see how much earth-moving is required for each, and decide at that point which appeals to you.

Personally, I would go as narrow as possible, while making sure everything I want to do is accomodated. The wider you go, the further into the hill you'll have to dig, and the more volume of soil you'll need to move.

Also, going narrow means that the retaining walls will be under less stress, and will need less height, decreasing their cost.

-CK
 
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Nh Ng
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I have a large area of land with pretty steep slope, ranging from 20-40 degrees. I hope to plant rows of shrubs onto that area. My problem is how to get access to all the areas to plant as well as to water. The area is very arid, only 8 inches of rain per year.

This is the pic: https://s9.postimg.cc/5zumjwlgf/slope.jpg


Walkway and railing for safe passage is definitely needed to tend for the plants. I initially hope to terrace the hill but it is too expensive with retaining wall and digging. There is access problem for the machine to dig.

Any ideas of what I could do with this land. It is such a waste to leave it empty like this.

My dream would be something that looks like a vineyard (may be less dense)  but with shrubs:
https://previews.123rf.com/images/aaron90311/aaron903111711/aaron90311171100034/89121498-green-tea-fields-in-boseong-south-korea-the-field-covers-the-whole-mountain-.jpg
http://palatepress.com/wp-content/uploads/2012/03/Seghesio-Rattlesnake-Hill-Vineyard-Sangiovese-by-Richard-Knapp.jpg
 
Casie Becker
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Okay, the promised pictures.   As you can see, it's a really tiny swale.  The second one is just to give you a better angle to see it.  Otherwise you might think I'm imagining things.  But even with a swale this tiny, this fig tree is doing much better than the one that died in the same location and better weather, last year.
20180604_103617.jpg
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20180604_103625.jpg
[Thumbnail for 20180604_103625.jpg]
 
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I wanted to mention that the general rule of thumb for maximum slope angle to have a swale is 18 degrees.  I don't recall why you don't want them on steeper land, or maybe I never really knew.  But anything steeper than 18 degrees should be a terrace, and I imagine that there's a maximum slope angle you would want to not use terraces as well.  I did a quick search for the 18 degrees slope and swales trying to figure if it was degrees or percent and I came across this thread which may help you out a bit.  Build a Swale on Steep Hillside
 
Marco Banks
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Nh Ng wrote:
Thank for the detail info. The slope is facing W/NW. It shapes more like an amphitheater.

My big problem is create safe access, stone path or dirt path so that I can get up there to tend for any plants.



A W/NW orientation will prove to be much less hot than anything facing S or W.  So that's good news.  You won't get those extra couple of hours of direct sunlight cooking everything in the late afternoon.

With a space that large, perhaps the first thing that you need to do is get out there and walk all over the land, getting a feel for the natural contours and elevation changes.  I would imagine that if you do that regularly, you'll start to see where your paths should naturally fit.

People tend to make pathways in one of two ways.  The first requires you to make some sort of centrally located "ladder" or "staircase" directly up the slope.  This is hard work and may require some money for materials to make it possible.  It's the most direct way to ascend the slope, but you'll need to build some sort of structure into the hillside to make steps that go up.  Then, from this centrally located vertical pathway, you would branch off every so often to have pathways that run on contour (like a swale).  So the staircase is the "trunk" and the pathways become the branches that go outward from the trunk.

The other way is more natural.  Rather than going directly up the hill, you create a series of paths that go diagonally upward, with switchbacks every so often to reverse the direction.  Your pathway then zig-zags up the hill.  That's how they build roads on hillsides, zig-zagging their way upward.  Its still a lot of work, but will be more natural.  It may not, however, give you as much access to the entire slope as the ladder/side branch method.

If it were me, I'd take it slow and just try to walk the land every day.  If you find yourself returning to the same route again and again, that's where you want to make your pathways.

Have you looked at any of Sepp Holtzer's videos?  He farms on a steep slope in Austria, yet he's found a way to make his land tremendously productive.  He uses heavy equipment to move the earth and has been doing this for decades, but just for inspiration, I'd watch a couple of videos and just pay attention to the way he's shaped his land over the years.
 
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I think what everyone else said makes pretty good sense, just adding this thought: if you want to try a lazy approach, grow a fast-growing vine at the base of the hill and treat it all as if it were a giant hugel bed.  Let the vine run amok over the surface of the hill, providing shade, temperature modulation, biomass as leaves fall off, and maybe even root mass if it's a rooting vine.  It'll be pretty easy to pull later if you want it gone, but it will cover any empty soil pretty quickly and give you a good yield.  (A squash, a gourd, something like that--a generous supply of water and nutrient is washing down that hill every time it rains, I gather).

Are the grasses on it really a "waste"? what is growing there? can you harvest biomass from it? graze a nimble animal?

 
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I definitely agree with spending as much time there as you can getting to know the area. There have already been lots of good suggestions for access.  Also its well worth getting to know all  the plants that currently grow there.  Where is this?  looks to me like a cold desert; Utah or eastern Oregon maybe? California?  Is that a cottonwood down by the parking lot?  If its warm enough for prickly pear cactus and you can find a source of spineless (or spiny if you are ok with it) pads, you can make a sort of swale by laying the pads out on a contour line. They will grow up and the area above will fill in with debris and you will have a real living swale with no digging.   Brad  Lancaster wrote about how his teacher in Africa did that, i think with agave.  In general his book 'water harvesting for drylands and beyond'  http://library.uniteddiversity.coop/Water_and_Sanitation/Rainwater_Harvesting_for_Drylands_and_Beyond_Volume_1.pdf will have lots of techniques that can be used to your advantage.  Also it depends on your approach, do you have plenty of money to hire people and buy supplies and make a quick job of the whole project like a highway landscaping job or is this a slow motion love affair between a human and their land; a project where you will spend your freetime in endless joyful hours watching plants grow, caring for them, and planting new ones?  One final suggestion I have is microcatchments-- chose a kind of tree that you want and that is fitting to your climate and create a small hand shaped water catchment for it that catches all the water that falls on an area about 3-5 times the area covered by the mature tree (depending on how dry tolerant it is). It may need supplemental water for establishment, but the microcatchment will multiply the annual precipitation available to it. This can allow you to break the project up into many small pieces.
 
Nh Ng
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It is high desert zone 7.

Most of the hill is covered by sagebrush which I really don't like.
 
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