A permaculture swale is a technique that captures water in the landscape for passive irrigation and for slowing runoff. Learn what a permaculture swale is and why you might need one in your yard. Oh, and don’t forget to grab your FREE DOWNLOAD: How to Build a Swale to Capture Roof Water Quick Start Guide at the end of the article.
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Irrigation for gardens and farms has always been a complicated subject. That’s because the possible solutions are as varied as the conditions on each property.
In permaculture design, we seek to solve problems in the landscape by working with nature and using techniques that are appropriate for the site.
For many gardeners and farmers, catching rainwater in the landscape can be a low-maintenance way to irrigate and improve soil quality at the same time.
When I started creating pockets of gardens and edible landscaping around my house, I wondered how I would find the time to hand-water all of those areas. And that’s when my love affair with the swale began!
What is a Permaculture Swale?
A permaculture swale is a shallow trench dug along the land’s contour, with a berm on the downhill side created with soil from the trench. All points along a contour line are exactly the same height above sea level.
Therefore, a trench along the contour captures water in the landscape, slowing and spreading it across the contour line. This action reduces erosion and retains water where it is needed.
The above picture shows contour lines in pink. These indicate that all points along a single pink line are the same height above sea level. The hillside slopes downward toward the bottom right corner of the image, perpendicular to the contour lines.
Potential swale trenches are drawn in blue, while the planted berms below them are green. Without swales, the water on this hillside would rush down and form gullies, taking precious topsoil and nutrients with it.
Permaculture swales can ease the effort of food production while improving the local ecology. Each swale has unique characteristics to match the site’s conditions. In fact, the above picture is showing large swales on a large farm field.
Lucky for us that swales are also applicable at a residential scale. See how I constructed a swale in my front yard landscape!
Tired of generic permaculture design advice that you can’t apply to your specific goals? If so, check out my Permaculture Design Program and get the tools and support needed to create and implement your own permaculture design.
Is a Permaculture Swale Right For You?
If this all sounds too good to be true, well, you might be right! Unfortunately, swales aren’t appropriate in all situations. They are great for gently sloping land, but not steep slopes. Also, on-contour swales might hold too much water in super rainy climates.
Keyline design and check-log terraces are a couple of strategies that have been used in these situations, and are worth exploring.
Keep reading to find out if a permaculture swale is right for you.
>>> Get more nitty-gritty details in my article How to Construct a Permaculture Swale.
Why a Permaculture Swale Could Be Helpful in Your Yard
- Mitigate stormwater runoff.
- Are an easier way to catch rain than using a tank or barrel.
- Are more efficient than tanks or barrels.
- Build self-sustaining ecosystems.
Let’s elaborate on each of those points.
1. A permaculture swale mitigates stormwater runoff.
Stormwater runoff is now the largest source of water pollution and is a huge problem in most cities. That’s because municipalities view water as a liability, so they send it away as fast as possible. With the existing infrastructure in cities, they’re right to be concerned about flooding.
However, sending water away as quickly as possible has resulted in horrible breaches of environmental stewardship. In my city alone, we send 13 million gallons of raw sewage into local waterways each year because the overtaxed sewer system combines stormwater with sewage during heavy rains.
We typically think stormwater is a problem that only governments, institutions, and experts can solve. In reality, there would be no problem at all if citizens did their part.
Though the problems of the world are increasingly complex, the solutions remain embarrassingly simple.” – Bill Mollison, father of permaculture, and author of Introduction to Permaculture and Permaculture: A Designers’ Manual
Here’s an example of how I did my part to help with the stormwater problem:
My 1200 square-foot house catches 30,525 gallons of rain from the roof each year. How much water does your roof collect? I capture 75% of that, or almost 22,900 gallons in our landscape.
What if we all caught tens of thousands of gallons of water in the landscape, where appropriate?
Me thinks that the millions of dollars of taxpayer money currently going to fixing the sewer problem wouldn’t be necessary. Quick everyone! Dig a free swale! 😉 It also means that aquifers would be recharged and watersheds would remain healthy and intact.
Water management is the foundation of a low maintenance landscape.
Learn more about permaculture-based solutions in my award-winning book, The Suburban Micro-Farm.
2. A permaculture swale is a more passive solution for catching rain than using a tank or barrel.
Catching rainwater in tanks or barrels takes a certain amount of engineering skill. You have to:
- Buy a bunch of parts.
- Connect the downspout to the tank.
- Link multiple tanks together.
- Route the overflow either back to the sewer or run the overflow into the landscape.
- Add mosquito dunks regularly and clean out the barrel at least yearly.
- Install a spigot for filling up a watering can or connecting a hose.
All of these parts eventually degrade with sun and weather and need to be fixed or replaced over time. What’s more, there is very little water pressure from rain barrels, so using the water is quite frankly a pain in the ass.
Believe me, watering by hand takes a REALLY long time without water pressure. The solar pump I tried didn’t work very well. I think the inventors know that because it isn’t on the market anymore. 😛
Look at all of that engineering and purchasing of parts for a water source that ADDS maintenance time! Catching water in the ground using a swale can be so much easier. It allows you to passively water the garden with little work after it’s all set up.
Now, if you have rain barrels, don’t worry. I have rain barrels, too! Check out how I planned the overflow and made our rain barrels as super low-maintenance as possible. Don’t let thousands of gallons of water go to waste!
If you’re going to capture water for irrigation, whether in the ground or in a container, be a good neighbor. Plan it out properly so that you don’t flood your neighbor’s basement!
>>> Learn more about permaculture.
You also don’t need a hillside for a swale to be useful! A gentle slope or flat land can also benefit from a swale.
3. A permaculture swale is more efficient than tanks.
Good soil is thirsty. Organic matter acts like a sponge, easily holding several times its weight in water. Toby Hemenway in Gaia’s Garden tells us that three quarts of dry soil can easily hold one quart of water.
When we translate that to the soil in our yard, if our yards were covered in one foot deep of rich, moist soil, it would hold as much water as a 3-inch-deep lake the size of the yard. It would be cost-prohibitive to install a container that could catch that much water.
But the soil will hold it for free!
4. A permaculture swale builds a self-sustaining ecosystem.
Swales catch water and direct it to where it’s needed, which is in the soil. Instead of water running off or pooling above ground, swales direct it downward into an underground reservoir.
Nature has its own built-in, self-watering system. When water is needed, it is naturally released. No work on our part after the swale is built!
This underground reservoir attracts microorganisms. Suddenly the soil is alive, and voila—we’re generating organic matter and fertilizer right in the place where we need it.
This means fewer inputs, which saves money and time. The more the organic matter builds, the more moisture it holds. With more organic matter, the system can better withstand both floods and droughts.
As the water reservoir and nutrients in the soil build, gardening will become a breeze for you.
Water management is the foundation of a low maintenance landscape.
Ready to construct a permaculture swale in your own yard?
See my article how to construct a swale in the residential landscape or check out my free download:
Have you built a permaculture swale on your property? What benefits have you noticed?
I assume experience with your property informs you about where the swales should be dug. It’s something we should be paying closer attention to. Thanks for the post, Amy. I look forward to Part 2.
Amy Stross says
Yep! I will talk more about choosing the best site for a swale in part 2!
I just found your blog via Commonsense Homesteading, Thanks Laurie! Anyway, I love this post. I am in Florida, however, and the land is pretty much flat, lol. Would I just make ‘canals’, lol or build up the growing areas? Or would it even matter? Thanks, looking forward to reading your blog and seeing the pictures of your gardens. 🙂
Thanks for visiting! I’m wondering what kind of soil you have where you live. Is it sandy? If so, you’ll want to make sure your swale is directly on contour. You’ll find contour on both flat and hilly land…all water drains somewhere. In sandy soil, you’ll want to make sure the berm is stabilized.
Using logs to line the berm and make it look like a raised bed would be a great way to stabilize it. The logs will decompose over time and add fungus and organic matter to the planting area. Plant the berm right away with deep tap-rooted plants like alfalfa, red clover, chicory, dandelion, and even tap-rooted trees like pecan, black walnut, white oak, or basswood. The taproots will help hold the soil in place.
Best of luck to you 🙂
I wouldn’t plant black walnut in your yard if you hope to grow other plants as well. Black Walnut tends to kill other plant life around it, this destroying any competition for resources. It won’t be long before nothing will grow under or around your black walnut tree. I know a local farmer that planted on of these in their front yard and it’s now the only living tree in that front yard. The only living plant because they kill off everything else. Unless you have a lot of space to work with I would avoid planting black walnut trees.
There are plenty of things that grow under black walnut trees. I’m looking out at my forest, which is lush and diverse. Plenty of black walnuts with lots of things growing underneath them. I go into this topic in detail in my book, The Suburban Micro-Farm. You can find an excerpt here: 30 Plants That Will Grow Near Black Walnut Trees.
Thanks for this – really helpful! I have a steeply sloping yard on the edge of a ridge so we get loads of run off. I’m
just now trying to figure out how to best use it. The area I would be most likely to build a swale is in heavy shade – any advice about how to stabilise it without easy access to sun loving plants? Thanks!
Shade-tolerant plants for the swale berm:
Trees: sugar maple, paw paw (although may not fruit in shade)
Herbs: ramps, columbine, aster, ginseng, ferns, Solomon’s seal, some chickweed
If the yard is really steep, say 6 degrees/10% gradient or steeper, a swale might not be the best option because it could potentially destabilize the hillside. Instead, consider check log terraces .
Good luck 🙂
I live in central Florida where everything is mostly flat. How would I go about building a swale for my garden area?
I envy your warm Florida weather 🙂 A swale in an area with a high water table can be a challenge (and sometimes not a very good idea–depends on the site), but be sure to use maximum width for the trench and berm as suggested in my post How to Construct a Swale. If your ground is totally flat, you’ll notice a natural area that accumulates water that would make a good location for a pond. If there is no area that collects water, then your land has enough of a grade to drain somewhere else. Use a level to mark the contour line for the swale site.
Karen Martin says
Love your ideas. I use a water tank to collect water. I will have to read and study your information. One more thing, please keep your cat inside for the protection of other wildlife. Thank.
i am sold on swales already but can’t seem to find a decent contour line. My property slopes North – South (major) to the road and EAST-WEST (minor) toward the driveway. Naturally the driveway acts as a berm chanelling massive amount of water and topsoil into the ditch. Is it advisable to dig a level trench 6 inches deep on one end and 1 1/2 foot deep on the other end? Naturally the overflow would ideally be on the uphill side.
With three acres and 40+ inches of rain we loose tons of water and topsoil. That is over 3.5 million gallons of water i want to keep. Granted i don’t lose it all but i do lose a significant amount especially during 2-4 inch rain events.
It sounds like your site is a bit of a challenge. Oftentimes we think of swales as being relatively straight or with a minor curve. However, sometimes like a meandering stream they can be quite wavy or zig-zaggy to accommodate a contour line.
It’s a challenge to give specific consultation without seeing your property, since what I envision from your description may not be what actually is. You’re thinking well to want to catch and slow the water coming from your driveway.
I would do my best to try to find a contour line – however wavy or zig-zaggy – because that will allow you to catch the most water without causing problems. If that isn’t possible, you could use a conveyance trench to “convey” water from the driveway to a swale dug on contour nearby.
As an example, check out the plans of our front yard rainwater catchment project, in which a conveyance trench moves water from our downspout into our front yard swale.
If you intend to dig a “swale” not on contour and level it out manually, a good safeguard is to put a rain garden in on the low end to capture any excess. It’s a good “just in case”, and is what we did in our front yard. Hope that helps.
Thanks for the help. I hadn’t thought of using a rain garden on the low side if the swale. It looks like a very bus
… like a very busy summer for me. Fortunately I have a good source of cardboard and grass clippings plus several cords of wood to build up the berm. Living on a major rural road I also have annual access to power line tree trimmers to add tree mulch to dug out areas. Probably let it mellow a year prior to mulching the berm. In the meantime clover and beans until time to plant tree guilds.
Once again thanks for the help.
Angi @ A Return To Simplicity says
I am really looking forward to building a couple of swales in our new orchard. There is a perfect contour slope that will make for a fantastic swale/berm area, and I can’t wait to get it started as soon as the ground thaws this spring! Thanks for sharing at the Homestead Blog Hop this week!
I’m excited for you and can’t wait to see pictures 🙂
Love this idea! Unfortunately in SE Louisiana any trenching would just build another canal. Will definitely use this if we ever move back to Missouri!
Susan Taylor Brown says
Thanks for your informative blog! We are just getting started with things on our new property. What caught my eye in this post was that it appears like your AC unit is raised up high. Is that because of the shape of your yard or did you do that on purpose in order to collect the condensation? Our AC unit is on a narrow sideyard and I am trying to figure out how best to capture the condensation as I think it might be able to keep the sideyard watered in the summer.
Nothing special about the heat pump unit in the side yard–that’s just how it was installed for venting purposes. It could be a good strategy for capturing condensation though 🙂
Susan Taylor Brown says
Ah, well you inspired me in any event. 🙂
Richard Gaylord says
Hi Amy, Your website has been interesting me, and I’m trying to formulate a plan before any digging, I’m 76 and want to get it right the first time. Our home is in Florida, near the Gulf, and South of St. Pete, West of Bradenton. We do have some slope to our yards, front and back. The problem here is deep sandy “soil”, mostly sand, which unfortunately, water percolates right down through, and a high cost of irrigation water, we have no well. We have draught periods we have to get thru, and swales would be a great way of holding & storing water in between rains, were it not for the sand. Our sponge would be directly draining down through it. I have wondered about using plastic sheeting at the bottom of a trench, it would be under compost of leaves and grass, soil & sand, to act as a barrier to water sinking away immediately. During the hot summer, it’s like a desert out there! Our backyard is covered in pebbles with a black clothlike membrane underneath, that doesn’t stop the weeds at all. I think first of all I need to start removing pebbles and make piles, sifting sand out of them and removing the crummy membrane… maybe that, shredded, could be used in the swales? I’m not sure but I think the pebbles could be used to help somehow also, there are lots of them! It’s really a difficult challenge, but somehow I think it could be dealt with positively. There’s no clay in the sand and little humus to help. Do you have any ideas? I like the swales concept; channel the rainwater from gutters and keep it in the spongy trenches, fight evaporation at the same time. We have spells of draught but heavy rains too, especially thru rainy season. If only one could even all that out! Thanks for getting me thinking and planning, right now I’m looking for some direction I guess. It’s a tough situation, I think. I might try some plastic deep in trenches and see how that goes.
If I were you, I wouldn’t dig swales. They are a lot of physical labor, and there are other solutions that can work for your situation. Organic matter is your friend in this situation, and will produce more lasting results than plastic. Especially if you are directing rainwater to the garden area. See this article about gardening in sandy soil for more ideas.
When we first moved to our place with 1.5 acre backyard there was a swale and we ensured they rebuilt it when we put in a pool. Unfortunately over 10 years of abuse- piling mulch in one section of the swale, watering it real well so it filled in and leveled out with excess grass growth where we backwash the pool- it has disappeared gradually. This was brought home with an 8″ in 6 hour rain which boiled out the dirt in a corner between our driveway and porch. The former swale is now funneling water into that area so action must be taken! Thanks for your advice.
Thanks so much for the article! I’ve been trying to find solutions for our swampy back yard and want to do it in a responsible, low maintenance way. One solution I came up with is kinda like the berm, swale idea but to use a natural, large, low spot and put a burm in it. Husband thinks it will create a larger swampy area but I figure the water will be absorbed by the added soil and plants. Any insight on that idea?
Berms in swampy areas are a wise choice, but you’ll want to figure out where the water is coming from that creates the swampy area. The berm would go just uphill of the swampy area, as a means of intercepting the water before it can pool up. Here are some ideas of what to plant to absorb the water both in the berm and in the swampy area.
My problem is that the the swale on my lot is not working. My neighbours turned the flow of the water from the roof to the. Back of the yard. I use a hose to take my roof water to the front yard. But, when it rains I am having water build up along the north side. The neighbour also has a garden against the fence.
What can I do to alleviate the water build up.
The city engineer blames the garden and water direction change.
It’s impossible to give effective advice without seeing the problem in person, so the BEST solution is to hire a permaculture designer or landscape architect to assess the problem. But here are some things to think about: Water always travels downhill. Gravity always wins. So how can you intercept the water that is building up where you don’t want it, and redirect it to where you do want it?
Is the swale in direct line of fire (err, water) to capture the water, slow it down, and spread it along the contour line? For that matter, is the swale built properly on contour so that when a leveling tool is run along the bottom of the trench, the entire length of the trench is level? Did you follow the instructions in my How to Build a Swale article?
LynDee Steiner says
I tried to build a swale and berm to catch runoff from our impermeable stone druveway and parking lot. It’s a lot about 120’x50′ with a slope in one corner, so all the water runs to the slope like a river when it rains! The water takes stone and gravel and mud with it and runs down the hill in my yard like a waterfall. I dug a ditch and laid in a 6×6 across the opening of the slope, and dug a curved swale from high end to high end. The water just poured right over the center of the berm like it wasnt even there. How do I build the land up to contour? Anything I use will just wash out and make more mess! The rushing water tore out all my juniper bushes planted on the hill below the berm, which is what it did before all my labors!
Did you follow the instructions in my article How to Build a Swale for how to use an A-frame level to mark the contour? If the swale trench isn’t dug exactly on the level contour, the water won’t go where you want it to.
The other issue is the steepness of the slope. If it is steeper than a 10% slope, then a swale would not help to mitigate your stormwater problem. Swales on steep slopes will only destabilize the land even more. If this is the case, then I would recommend multiple check log terraces instead.
There’s only about six feet between my house and my next door neighbor’s house. I want to direct water away from my house, which has a nice natural slope downwards from front to back. A friend suggested a swale, but in your article you stated that I’d need 10 feet from the house (and from my neighbor’s). I’d only have a few feet to work with. Do you have a suggestion? Thank you in advance.
If I understand, the ground slopes toward the back of the house. So you intend to direct the water toward the backyard, downslope? If that’s true, then you would create a swale on contour (parallel to the house) in the backyard, making sure that the location of the swale is 10 feet from your neighbor’s house. Downspouts can be directed to the backyard through drain tile or PVC piping so that no wayward water is tempted to run toward your neighbor’s house.
So interesting. All my water goes into the retention ditch. In the spring I consider getting an alligator and a bridge. Does that make this unnecessary? Or more complicated?
Well, it depends. Every situation is unique. If you have a large garden or landscape that you need to water in the summer, then allowing all of the rain to go to the retention ditch doesn’t do you any good. Unless you’re tapping that retention ditch when you need to irrigate a garden. A swale, in the right context, allows you to passively catch and hold that water in the soil until you need it. However, if you have a lot of rain year-round and don’t need to irrigate, then sending rainwater to a retention ditch is probably a better solution.
Hi, Amy! We have a gradual slope on two sides of our house from where the property had to be graded for the house. It occurrd to me that this might be a good place to add two swales (the slope is about 25 feet from top to bottom) and plant fruit trees. How deep should swales be for trees, and should I guild the trees on the swales, or just plant a green mulch? Any help appreciated!
Hi there! Yes, this sounds like it might be a good place for swales to capture and sink the water running down the slope. The question is not ‘how deep should swales be for trees?’, but rather, how deep should swales be to capture the amount of water that comes rushing down the slope during a heavy rain?
This can be difficult to calculate, and will depend on rainfall, soil type, etc. Follow the instructions in my article How to Build a Permaculture Swale. Then watch during a heavy rain event to see if the swale trench overflows. If it does, then you need a deeper, wider, or longer swale. Once your swale is properly sized to accommodate the rainfall on your site, then you can plant the fruit trees in the swale.
Guild or green mulch — that is entirely up to your personal preference. Either is good. 🙂
Hi Amy! I live in the high desert of NV and we have hot dry summers and plenty of snow in winters. So not much runoff.. Would a swale benefit us?
If you have any wet events at all, say, a day of wetness following snow melt + a gentle slope, then a swale might be a good fit for you. However, a swale is just one component of a water-wise garden system.
You might like reading chapter 5 of Gaia’s Garden, which highlights a water-wise garden in the high desert of Los Alamos, NM.
Melissa Elliott says
I just found your website. I live in Colorado. I have a Southeast corner in my garden where almost everything died due to heat and lack of water, despite using native, drought-tolerant plants. I like the idea of a swale in that corner. There isn’t a slope there, but maybe I could direct water there from other areas? That might be too complicated for now. If I catch a little rain water that would help. Thank you. I may return with questions.
Swales capture water when a natural slope and gravity brings water down to a particular area. If your land is flat, or if the spot is a high point, then a swale is likely not going to capture water there. Perhaps a rain garden might work, more intentional mulching, or simply taller things that provide afternoon shade are better strategies.
I built a few swales and watched during a heavy rain. The swales worked well…almost too well and the sandy soil in the swales really soaked the water away from the berms quickly. A friend suggested a pond liner under the rock/mulch path planned in the swale but I was hoping for a more permeable but slower draining solution. Do you have a suggestion?
I also bought the book and love it as a reference ❤️
Rich soil absorbs and holds more water for longer, so the first step I recommend is to add really good compost soil and/or worm castings. Swales are meant to be tree planting systems. As soon as plants are established there, they will hold in moisture. I personally would not use a pond liner.
Jane Mulder says
My house is holding water in crawl space. I am downhill from a hill. What if I dig into the ground next to the right side of my house where the water comes in and put down heavy plastic then put mulch or top soil on top of that. I could also carry the ditch down to the back with heavy plastic to move it on downhill in the back.