A lesson in the need for swales...

Wow, I knew it would be good to put in some swales but I really didn't realize how badly I needed them!

For most of my property, it is generally "flat" (expect for in front of the largest pecan where I was planning my first berm/swale to slow water loss) and the soil is sandy loam so I *thought* I was getting good water absorption during rains. This morning, I realized that my thinking was fantasy. Last night, we had a thunderstorm -- huge deluge of water. I was happy because my plants and trees were getting watered. This morning, I go out to gather forage for the rabbits' breakfast and I'm pulling up grasses out of the mulch around one of the plums...and the roots were coming up with dry soil less than an inch below the surface! it should have been wet further down than that!

Okay, so now I realize I need to dig a serious system of swales around my trees and planting beds but that leaves me with some questions:

1. do I leave the swales bare or fill with straw or tree mulch?
2. from June to October is "hurricane season" and we can get a LOT of rain in a few days time from Nor'easters, Tropical Storms, and of course, hurricanes. How do I plan for those events with my swales in order to capture the rain?

Well, I'm also very new to this but have enough of an understanding to relay the following points:

1) Always plant the berm of a swale. There are tons of cover crops you can select for your area if you aren't ready to plant your permanent residents. FWIW, I planted PVFS Summer Soil builder on mine. It will grow all summer, I can chop and drop a few times during the season, and has helped resist erosion. Come fall, I'll plant a cool weather crop, chop and drop that, and things should be primed for more permanent plantings next year.

I suppose you could just mulch it, but live plants with roots are going to do a better job in that application. Green mulch, right?

2) Your property design should include not just the system of swales but also where they will overflow and how you will direct the overflow water. They can overflow into a pond, or through a sill (a level break) in the swale and run into the next layer of swales. It's like when Geoff Lawton says to design a desert space - you in fact design for a flood because the rain events they do get are massive and the runoff is huge. You need to design ways to capture that in your property.

I wouldn't break out the excavator until you have a comprehensive design for your property.

Hope that helps.

Brad D'Amico wrote:Well, I'm also very new to this but have enough of an understanding to relay the following points:

1) Always plant the berm of a swale. There are tons of cover crops you can select for your area if you aren't ready to plant your permanent residents. FWIW, I planted PVFS Summer Soil builder on mine. It will grow all summer, I can chop and drop a few times during the season, and has helped resist erosion. Come fall, I'll plant a cool weather crop, chop and drop that, and things should be primed for more permanent plantings next year.

Well, yes, but I've seen where folks dig swales around trees--like moots around the tree. Do they fill those swales with mulch or leave them? let grass grow there or plant a groundcover?

Brad D'Amico wrote:I suppose you could just mulch it, but live plants with roots are going to do a better job in that application. Green mulch, right?

2) Your property design should include not just the system of swales but also where they will overflow and how you will direct the overflow water. They can overflow into a pond, or through a sill (a level break) in the swale and run into the next layer of swales. It's like when Geoff Lawton says to design a desert space - you in fact design for a flood because the rain events they do get are massive and the runoff is huge. You need to design ways to capture that in your property.

I wouldn't break out the excavator until you have a comprehensive design for your property.

Hope that helps.

Yes, it is helpful. Now, want to pull out the paper and markers and draw up a comprehensive design plan for me? I have watched a Lawton video or two on how he puts together a design plan for a property and it all sounds logical until I try to translate that to my little plot. I get majorly overwhelmed and confused and after I stop hyperventilating, I go back to winging it....not a good option I admit but I just really truly do not know how to go from what is to what can be and figure out how to convert it one step at a time in a logical way...

Tina Paxton wrote:
Well, yes, but I've seen where folks dig swales around trees--like moots around the tree. Do they fill those swales with mulch or leave them? let grass grow there or plant a groundcover?

According to this:

you plant all but the bottom and you could plant that if it was a plant that liked wet feet.

As for design, consider taking a PDC or get someone to design it for you.

Cj Verde wrote:you plant all but the bottom and you could plant that if it was a plant that liked wet feet.

As for design, consider taking a PDC or get someone to design it for you.

Very helpful visual! Thanks.

I'd love to do a PDC if I can afford it and not have to travel to do it. Is there a list on permies somewhere of where PDCs are offered?

I did Geoff Lawton's last year which was awesome and my husband is doing Jack's PermaEthos this year. Maybe try to find someone near you who needs a property to work on for their design.

Try in this thread.

It is interesting that you feel a dry soil condition on relatively flat land warrants a swale. A swale on the contour of a slope is intended to slow and capture surface water that would otherwise run off and possibly cause erosion. It doesn't sound like you have this condition???

Michael Vormwald wrote:It is interesting that you feel a dry soil condition on relatively flat land warrants a swale. A swale on the contour of a slope is intended to slow and capture surface water that would otherwise run off and possibly cause erosion. It doesn't sound like you have this condition???

The condition we have here in the South is that the soil dries out between heavy downpours. A common soil found here is easily draining sand on top of compacted clay, which makes the situation even worse. That's why big, old trees do very well, they have their roots deep down in the clay where it is still moist, but annual row crops have a terrible time. By the time a zucchini has sent roots down to the clay, a 2 week dry spell has the top of the clay as hard as a sidewalk. Then we get 4" of rain in 3 days and the zucchini that was struggling triples in size. But all that was from surface moisture; when the next 2 week dry spell hits, and the root system of the zucchini hasn't kept up with its vegetative growth, the vines will all wither away.

So you can see why it would be nice to have a swale that can store some of that water for later. And a swale filled with organic matter that can hold water, well that's even better. Cover that brush-filled swale over with some topsoil and plant on it, and you are doing hugelkultur.

Michael Vormwald wrote:It is interesting that you feel a dry soil condition on relatively flat land warrants a swale. A swale on the contour of a slope is intended to slow and capture surface water that would otherwise run off and possibly cause erosion. It doesn't sound like you have this condition???

Generally speaking, a permaculturalist is going to recommend swales for soil that is too dry or too wet (the uncompacted mound dries out quicker). Regardless of slope. Geoff Lawton even shows what swales can do in Holland.

I know you disagree so I'm wondering what is your recommendation for fixing dry soil on flat land?

Cj Verde wrote:I know you disagree so I'm wondering what is your recommendation for fixing dry soil on flat land?

MORE RAIN - (couldn't resist)

Seriously though, I'm just not sure I see how an 18" trench on relatively flat land is going to solve the problem of a soil that drains too well.

A large amount of sandy soil over rock or clay is surely a problem, not unlike desertification. We could borrow from Alan Savory's playbook, but it's unlikely herds of livestock are in order in this case either. I would say the answer is a lot of organic matter, but then it burns up pretty quickly in the south. Perhaps a lot of organic matter and heavy mulch?

Michael Vormwald wrote:

Cj Verde wrote:I know you disagree so I'm wondering what is your recommendation for fixing dry soil on flat land?

MORE RAIN - (couldn't resist)

Seriously though, I'm just not sure I see how an 18" trench on relatively flat land is going to solve the problem of a soil that drains too well.

A large amount of sandy soil over rock or clay is surely a problem, not unlike desertification. We could borrow from Alan Savory's playbook, but it's unlikely herds of livestock are in order in this case either. I would say the answer is a lot of organic matter, but then it burns up pretty quickly in the south. Perhaps a lot of organic matter and heavy mulch?

Tons of mulch is definitely needed to provide something to sponge up the rain as well as nutrients. I am working on that as well. But, when I think of the quantity of rain that can fall here during a single storm, I hate to not try to trap it in some way. When I think of how much rain a single fruit tree requires on a regular basis -- I need to trap rain! I am also planning a secondary water system incorporating a small "duck pond" with a drain pipe to distribute the fertilized water to the planting beds.

Michael Vormwald wrote:I would say the answer is a lot of organic matter, but then it burns up pretty quickly in the south. Perhaps a lot of organic matter and heavy mulch?

Aha! Guess what would provide organic matter and heavy mulch?

N-fixing trees planted on a swale!

Michael: It seems like you may be overlooking some of the other functions of a swale. Like most things in permaculture there are multiple functions happening here, not just preventing erosion. For that matter just because your soil isn't washing away doesn't mean that your soul is absorbing all of that water. Good stable soil with lots of vegetative growth will sheet water on relatively flat ground without losing soil. In this situation I think that anything you do to hold the water in a given area longer the better off you will be. Some nice swales with plenty of organic matter and mulch laid in there would be my suggestion. With this approach you build organic matter in the soil over the long run while retaining moisture more effectively in the short term. The swale and berm can be used to create the high organic levels that you would be looking for to alleviate this problem. These systems give you a short and long term solution. That is how an 18 inch swale turns into a foot and a half of choice topsoil with a little labor upfront and reaping the benefits for the next decade. Permaculture long game stacking functions and giving gifts to your future self....how could you go wrong.

Okay, I suppose you could dig a trench and fill with organic matter to create some localized capture of excessive rain...but I don't think we'd call it a swale.

I think for where the OP is at in terms of their property development, until a design is complete and the plan for earthworks put into place - sheet mulching the areas to be planted is definitely the answer here.

A layer of cardboard, topped with layers of compost, topsoil, straw, and topped with a thick layer of hardwood wood mulch will put the OP off to a great start in the area(s) to start with.

The other thing she could do is a "biological keyline" aka planting deep rooting plants like daikon and leaving them in the soil to decay, opening up pathways for water going deep into the soil.

Nobody has mentioned biochar yet. That's how you get organic matter into the ground that doesn't go away after one steamy Southern summer. If you are not charring some percentage of the biomass that is going into the swales, you're just going to be making the same number of wheelbarrow trips next year. Lately, I've taken to mixing in two shovelfuls of biochar for every wheelbarrow load of wood chips that I spread as mulch. Maybe when the weather cools down in the fall, I can do more biochar burns and up that ratio. Somehow, when it is 90 degrees, I have very little motivation to fire up the biochar barrel.

If you put 3 or 4" of biochar into your swale, that should change things for the better.

John Elliott wrote:Nobody has mentioned biochar yet. That's how you get organic matter into the ground that doesn't go away after one steamy Southern summer. If you are not charring some percentage of the biomass that is going into the swales, you're just going to be making the same number of wheelbarrow trips next year. Lately, I've taken to mixing in two shovelfuls of biochar for every wheelbarrow load of wood chips that I spread as mulch. Maybe when the weather cools down in the fall, I can do more biochar burns and up that ratio. Somehow, when it is 90 degrees, I have very little motivation to fire up the biochar barrel.

If you put 3 or 4" of biochar into your swale, that should change things for the better.

I'm assuming that "biochar" is burnt plant matter -- wood I would presume is the most likely? -- and you are adding it and the ash both to the beds/swales/berms along with mulch? While I know that wood ash is good for the garden but please explain the benefits/effects of biochar?

While I know that wood ash is good for the garden but please explain the benefits/effects of biochar?

Biochar is like organic material in that it retains moisture, yet doesn't break down. It also has a huge surface area which is home to the benificial bacteria in your soil.

Michael Vormwald wrote:Okay, I suppose you could dig a trench and fill with organic matter to create some localized capture of excessive rain...but I don't think we'd call it a swale.

If it was on contour and you took the dirt from the trench and placed it on the downhill side, then planted trees in that dirt, it would be a swale.

Tina Paxton wrote:
I'm assuming that "biochar" is burnt plant matter -- wood I would presume is the most likely? -- and you are adding it and the ash both to the beds/swales/berms along with mulch? While I know that wood ash is good for the garden but please explain the benefits/effects of biochar?

Here's the lazy way most efficient way of putting in your swales:

1) Use a square end shovel to cut the sod in your yard and just flip it over. Depending on how sandy your soil is, you may have 1" of sod or 4", but turn over whatever thickness holds together in the shovel.

2) Once you have your sod squares flipped over and arranged the way you want them (at the drip line of your trees?), you have to decide how deep to make your swale. Just dig more dirt where you exposed it and use that to build up the top of the inverted sod squares. You don't have to do a lot of excavation. I have a couple of natural swales in my yard and they are no more than a foot deep (below the natural grade). They can take 2 or 3 days to dry completely after a heavy rain. I know they are doing their job, because the asparagus and blackberries along the side are doing very well.

3) When you rake leaves or trim brush, throw it in the swale and let it dry out. Then burn it (assuming you are in an area where the local fire department won't have a fit). Get a good bonfire going in the swale and let it burn down until it is mostly coals and not much flame. Like when you get ready to barbecue. Then douse it good with the hose. By not letting the fire completely burn out, what you have done is to create a lot of biochar in the swale. If you pile the brush and some pieces of scrap lumber 18-24" high, it will burn down so that you may have 3" of charcoal (biochar) in the bottom of the swale. Making biochar really reduces the volume of biomass.

4) Then you can leave the biochar in the bottom of the swale, maybe plant some flowers on the top of the built up part, but there's not much more work to do. Except inoculate the biochar -- and nature will do that. You can speed up the inoculation process by throwing some compost or emptying the cat box into the biochar lined swale. One thing about charcoal in the bottom of a swale, it will not stink. Anything that would smell bad is going to be quickly broken down by the bacteria living on the biochar.

This advice probably goes against the good-ol-boy aesthetic of a FLAT lawn that you can easily go over with your riding lawn mower while drinking a beer. But that's not permaculture. Permaculture makes use of features like irregular topography. And when you live in the "low country", the only topographic features like swales are where you build them.

In this situation we were speaking of relatively level ground ... the problem is that it is fairly sandy soil that drains very quickly (and is likely prone to rapid evaporation as well).

brad millar wrote:

Michael Vormwald wrote:Okay, I suppose you could dig a trench and fill with organic matter to create some localized capture of excessive rain...but I don't think we'd call it a swale.

If it was on contour and you took the dirt from the trench and placed it on the downhill side, then planted trees in that dirt, it would be a swale.

Forget the relatively flat ground for a moment.

If the soil is sandy, drains quickly, and is prone to evaporation, then you need trees with light canopy to help shade and to produce organic matter and if you choose wisely, they'll fix nitrogen in the soil too. Best way to grow trees that are self-irrigating - plant them in the uncompacted mound of a swale.

As to the original question, it was about dry soil around fruit trees. Geoff Lawton recommend 9 support trees (N-Fixing) for each productive tree. So putting in a swale around the dripline of the fruit tree and then planting with N-fixing trees would kill several birds with one stone. Plant comfrey between the swale and the tree and you'll really be providing great mulch, building up the organic matter of the soil.

Attempting to quote John Elliot here -- not sure I'm using the Quote function correctly:

3) When you rake leaves or trim brush, throw it in the swale and let it dry out. Then burn it (assuming you are in an area where the local fire department won't have a fit). Get a good bonfire going in the swale and let it burn down until it is mostly coals and not much flame. Like when you get ready to barbecue. Then douse it good with the hose. By not letting the fire completely burn out, what you have done is to create a lot of biochar in the swale. If you pile the brush and some pieces of scrap lumber 18-24" high, it will burn down so that you may have 3" of charcoal (biochar) in the bottom of the swale. Making biochar really reduces the volume of biomass.

UM, while I like your method of making shallow swales, I'd say that's not really biochar -- that's charcoal. By burning the wood in open air you're getting aerobic combustion, and not forcing the gasses out, burning them, while leaving the cellulose structure. Lots of CO2 and smoke released, too.

To create biochar, here's one simple way: https://www.youtube.com/watch?v=svNg5w7WY0k&index=1&list=PLCeA6DzL9P4vhMbHjDUmL2hlEPMssyL1i

This is a workshop held in Western Mass (Northfield or Colrain Elementary School??) by Bob Wells, who has a whole series of videos and pretty regularly runs workshops about enriching soil and sequestering carbon with biochar. Not the only way to go, but certainly something any of us could do on our homesteads, community gardens, etc...

UM, while I like your method of making shallow swales, I'd say that's not really biochar -- that's charcoal. By burning the wood in open air you're getting aerobic combustion, and not forcing the gasses out, burning them, while leaving the cellulose structure. Lots of CO2 and smoke released, too.

Right you are, Brad, it's not inoculated, but it will be over time. I think we get a little too high tech when thinking about biochar. If you do a thought experiment about what was going on in the Amazon jungle 10,000 years ago when terra preta soils were being formed, you can imagine that people wanted to clear a field and so they cut brush and piled it up. Then they set it on fire. But being the Amazon, it only burned for a few hours until the afternoon thunderstorm popped up and put it out. Just the conditions you described. Fast forward 10,000 years, and we now consider these the biochar rich soils that have changed our thinking.

OOPS! Correction Time...

I thought the Bob Wells 5-part biochar series was from a workshop he held in Western Mass., but I was entirely wrong. It was done at Living Web Farms, in Mills River, NC.

Nonetheless, he gives a great deal of detail on how and why to make and use biochar. Too bad that the two main speakers are also in the business of selling biochar products, but since they give away the basic trade "secrets", they are also helping all of us on limited budgets to make our own. Many Permies will decide to make their own, while commercial farmers, strawberry growers and nursery owners might opt to buy the stuff. I'm keeping my eyes out for barrels and stovepipe to build my own retort.

As for the charcoal in the Amazon and the formation of Terra Preta, that will work -- obviously, since it is now an accepted historical fact -- but it could take a very long time to reach maximal benefit, and burning the wood in air puts more pollution into the atmosphere than burning off the gasses to make true char.. The ancient people who built up those soils may have done so for hundreds, or even thousands of years. We don't have that much time. AGW and Climate Chaos is already upon us, so I favor making clean biochar instead of charcoal since 1) we know how; 2) it's pretty easy with some tweaking; and 3) its really inexpensive, or even free if you are a good scrounger and have access to woody biomass.

Hey, Tina. It sounds like we have similar growing conditions. I'm in northeast Florida, growing in 100% Tavares fine sand (gray sand, pretty far down). I've been where I live now for almost two years. When I first moved here, the house and yard were really neglected. The whole back yard was a 4-5ft tall field of spanish nettle. I had this design in mind for a fruit & veg garden growing in a labyrinth pattern. I got the opportunity to start working on that design here, and the first thing I did was dig a 40ft diameter, 2ft deep, 2ft wide trench around where I wanted to make the labyrinth. Took me a while, but I basically made a submerged hugel bed, and kept piling it up about another foot or so, then planted it with whatever I was starting, as I was starting (I can see where I completed sections in time for winter veg, and sections where I planted my summer veg, but it's starting to get really scattered now). That had definitely been my saving grace out here. Last summer during some heavy tropical storms I took a shovel out while it was raining, and found where the rain was collecting, and made mental notes about how much of that area looked like a little bog, and what areas felt like the lowest spots. I carved a little swale, and then piled wood above it (like a berm/swale design on contour with the little bit of topography I do have here--*very* marginal!), and dug another swale above that berm. I didn't layer as many "greens" in that berm as I did in my submerged hugels, so it's looking pretty dry and inactive there. But I filled the swales with compost, leaves, sticks, and greens (mostly spanish nettle), and planted it with sugar cane. I've now got elder, lemongrass, and watermelon seeded in my swales.
I have rain barrels that are a kind of stressful system right now. My gutter might be slightly uneven (there is a guard to keep leaf litter out of it, so I don't think there's an obstruction), so all the rain that hits this panel of my roof flows to one corner, instead of evenly flowing toward two corners. And the one corner happens to have a septic tank almost immediately underneath it (fantastic planning, whoever built this house!). So if I don't have three barrels and if I don't have two of them connected to hoses so that they start draining as soon as they start being filled, I'd have a cracked tank. But that's where the swales/hugels planted with my water-lovers comes in handy. Four feet away from my swale/berm is my hugel planted with seminole pumpkin. I'll alternate between the top swale, the bottom swale, and the hugel as far as where the primary barrel's hose takes the water.
People in temperate zones might have a hard time imagining places where comfrey and stinging nettle, dandelion and burdock are hard to find. If the primary reason for growing comfrey for green manure is that it grows right back after being cut to the ground, then spanish nettle meets that requirement. Spanish nettle will grow in sand, with little rain or with torrential rain, in 60 degrees or 90 degrees. I like to let it cushion some of my transplants when they're too little to tolerate the spring/summer climate, and then as they need more sun, just cut a fistful of spanish nettle. In some areas I have laid down oak leaves to suppress the dollarweed and other volunteers. When the spanish nettle comes up, I just let it get to about 1-2ft tall, or until it shows signs of going to seed, and then I cut it to the ground. I might use that as a green layer for my lasagna compost, or I might drop it there and cover with more leaves. Bees also love it, and you'll never be in short supply.

You might also be interested in chinampas, if you get so much rain that you have some real flooding problems. Or just as a neat way of building up some terrain for different plants' different needs.

Michael Vormwald wrote:

Cj Verde wrote:I know you disagree so I'm wondering what is your recommendation for fixing dry soil on flat land?

MORE RAIN - (couldn't resist)

Seriously though, I'm just not sure I see how an 18" trench on relatively flat land is going to solve the problem of a soil that drains too well.

A large amount of sandy soil over rock or clay is surely a problem, not unlike desertification. We could borrow from Alan Savory's playbook, but it's unlikely herds of livestock are in order in this case either. I would say the answer is a lot of organic matter, but then it burns up pretty quickly in the south. Perhaps a lot of organic matter and heavy mulch?

I had to chime in as I have flat land. For me, the wind pushes everything past. Where I have fences and plants and divets the wind can't push it past and it collects. My most successful trees are the ones planted on the wind side of my lean-to. Why? Because the snow collects there in massive mounds and leaves the ground wet. So how can I make the wind work for me? By letting it blow what I need where I want it. That would be swales.

Last year we had Brian Kerkvliet help us design and implement a swale system on our 1/2 acre urban lot, and blogged about it here:
https://integralpermaculture.wordpress.com/tag/swales/

At that link you'll also find the Peak Moment TV interview with Brian about how he uses swales to "shape water and soil" at his 12 acre Inspiration Farm site, where he will be hosting a PDC course in August.
https://permies.com/t/35357/cascadia/PDC-Inspiration-Farm-August

OK - no expert here , but seems like you have two separate but related problems going on.

First handling the "intermittent " huge runoff that the clay creates in southern soils and second doing something to create a better soil environment. ?

Swales work , but involve knowing your land- walking it , feeling the contours and mapping it out- where are the areas the run off travels.? What can you do to send it where you want it to go? Why do you want to go it to that location?

Sit down where you want a swale and really look around.. think about it. Don't be in a hurry... If you don't like drawing it out - build a model - use your steps to measure approx. where things are - reduce it down- one step =one finger width .. LOL People learn in different ways...trust your land and your eye...

Our soil is clay base with sandy loam on top- have a similar problem. Our solution has been to build diversion swales into our pond and use raised beds until we can build enough good soil to help hold it- Winter rye has deep roots , that loosen the clay and add nitrogen to the soil. it can be cut and turned under in the spring.
We break the surface just enough to allow the good bio to contact the compost and soil we lay down- and let nature do her job. It is labor intensive and takes a period of time, but it makes your soil better, reducing the amount of runoff

John Elliott wrote:
3) When you rake leaves or trim brush, throw it in the swale and let it dry out. Then burn it (assuming you are in an area where the local fire department won't have a fit). Get a good bonfire going in the swale and let it burn down until it is mostly coals and not much flame. Like when you get ready to barbecue. Then douse it good with the hose. By not letting the fire completely burn out, what you have done is to create a lot of biochar in the swale. If you pile the brush and some pieces of scrap lumber 18-24" high, it will burn down so that you may have 3" of charcoal (biochar) in the bottom of the swale. Making biochar really reduces the volume of biomass.

While I agree with the rest of the post I'd advise against this bit. At least as written.

If you burn anything large enough to produce "char" and not just ash, you're highly likely to sterilize the soil near your new swales. The exposure threshold for cell thermal death is much lower than you'd think - 60C for 60 seconds. Lower temp for longer time period works the same (e.g. 40C for 10 minutes or something along those lines). So you might get away with burning leaves in the swale (which burn hot but go out fast) but anything with any "residence time" (i.e. anything big enough to produce coals) will roast everything too close to it. This includes critters/bacteria/fungi in the surrounding soil as well as any plants growing adjacent to the newly created swale.

I'm all for efficiency, but I think we can agree it's not really efficient if you have to replant a bunch of stuff or wait for all the soil critters to move back into the area. (Which will take a while. As in months.) If it were me, I'd do the extra work to make the biochar somewhere else and then cart it over. And yes, as someone else already pointed out, there are more efficient ways of making charcoal.