Earthworks & Earth ResourcesSwales

The Transition from Swales to On Contour Hedges

One of permaculture´s most famed and acknowledged contributions to sustainable land management and ecologically sound agricultural practices are swales. From Australia to Finland to South Africa, thousands of permaculture practitioners from around the world have taken their laser levels, A-frame levels, and Bunyip water levels to map out the contour lines across the landscape that holds them. Once stakes have been placed across the contour lines across the land, either a backhoe, or a strong back and a hoe carve out shallow ditches that are meant to hold water in the landscape, prevent erosion, and accelerate the natural succession towards richer topsoil and more vibrant landscapes.

There is absolutely nothing more satisfying for a permaculture farmer than to walk through his fields after a 2 hour long downpour and see puddles of water standing still in the ditches/swales that he had previously dug out. That water, which otherwise would have run over the landscape taking with it fertile topsoil for future crops, is now slowly infiltrating into the land, adding to the long-term resilience of the land to withstand drought. At the same time, the delicate layer of topsoil remains intact and, like a sponge, soaks up the excess water that is soaking into the land.

The Problem with Swales

Despite the obvious benefits of swales to land and water management, anyone who has built their own swales also knows that they can be a major challenge to maintain year in and year out. As excess water and soil accumulates along the contour lines of swales, they quickly become a hotbed for production and pretty much anything will quickly grow there. After a wet spring, you´ll find that your neat contour ditches now resemble a mini-jungle as the ditch itself is literally engulfed by the growth of organic matter.

While swales will continue to capture water, when left alone and not cared for, they do quickly fill in due to the massive growth of biomass. Those of us who have wanted to maintain the full “water-catching ability” of swales know that it does take a heavy dose of work to maintain the swales free from plant growth. At least twice during the growing year, it is necessary to go through the system of swales with a hoe and shovel to clean out the accumulation of organic matter and soil that threaten to fill in your expert water-catchers.

Not only is this hard work that is labor intensive, but it also requires frequent upturning of the soil which ironically leads to the diminishment of the very soil food web that your swales are trying to protect.

Might there be a way to use swales as a short-term solution to protect your soil and manage the water entering your land while slowly transitioning to a longer term answer?

On Contour Hedges or Tree Lines

A thick row of densely planted shrubs or trees is just as capable of stopping erosion and aiding the infiltration of water into the landscape as swales. The problem, of course, is that it takes time (often several years) to grow trees or shrubs into a decent enough size where they will be useful for that purpose.

One of the guiding principles of permaculture is to always think in the long term. As the Anishinaabe Indigenous People remind us, it is necessary to think seven generations ahead for any action that we undertake. In the case of swales, maybe we should begin to ask ourselves if our great-great-grandchildren would want to inherit the task of digging out the swales we originally put in, year in and year out.

Instead of burdening future generations, and your aging back, with the task of swale maintenance, a longer term solution would be to plant a hedge or tree line on the downside of your swale at the same time you dig the swale. Many quickly growing species can grow thick enough and tall enough within 2-3 years to essentially replace the functions that your swales were providing. Maintaining your swales for 2-3 years is much preferable to maintaining them for a lifetime.

The trees or bushes that you plant on the downside of your swale will also benefit from the excess water and fertility that accumulates along the contour lines of your swale. If you live in an especially wet climate, it might make sense to plant water-loving or water tolerant species such as elderberry or alder so that they can take full advantage of the excess water they will have access to.

The Multiple Functions of On Contour Hedges

As with all things in permaculture, it is important to always attempt to assign as many functions as possible to any element that you include in your overall system design. In the case of on contour hedges, they essentially assume the functions of the swale; helping to avoid erosion and infiltrate water into the landscape. Excess rainwater will run into the on contour hedges, spread across the contour line, and slowly infiltrate into the landscape.

Additionally, hedges offer other functions to the system that swales do not. Hedges add abundant organic matter that only further increases the ability of the soil to hold water through improving the fertility and organic matter content of the soil. You can choose to plant certain quick-growing nitrogen fixing species for your on contour hedges such as alder and black locust. These species respond well to heavy pruning which will give you an abundant source of mulch material while also fixing enormous amounts of nitrogen in your soil.

Of course, you could also choose to plant food-bearing species in your on-contour hedge, including shrubs such as sea buckthorn (also a nitrogen fixer), dwarf mulberry (a great food source for chickens and easy to prune), goumi (nitrogen fixing and delicious berries) or even small fruit trees interspersed with nitrogen fixing shrubs.

The Transition Towards Sustainability

While swales certainly are an important contribution to sustainable land management, our experience shows that they are best utilized early in the succession phase or early in the process of restoring the ecological resilience of the landscape. As with all things in permaculture, searching for other solutions that offer longer term solutions with more beneficial functions to the overall functioning of the landscape is essential. Transitioning from swales to on contour hedges might just be a strategy worth exploring if your back is telling you that it has had enough of cleaning out your swales.

Tobias Roberts

After working in the development industry for over a decade, Tobias decided it was time to stop advising Central American farmers how to do things if he didn´t have a piece of land to live coherently with what he taught. Together with his family he runs a small agro-forestry farm, tourism cooperative, and natural building collective in the mountains of El Salvador.


  1. Absolutely, especially in the tropics; the growth from a swale is a daunting task, and the weeds even outgrow the leguminous trees in the wet.

    On my little farm here in Ecuador I am doing similar, using the SALT (Sloping Agricultural Land Technique) system, which is essentially planting leguminous trees in a double hedgerow on contour. This first year I have made a series of small swales and tried planting on the lower slope… the weeds just overtook it, I tried seedlings and cuttings, but neither could compete. Crazy.

    This year I will be planting seeds/seedlings in the dry season and manually watering until they can get at that lower moisture… I hope. If the seedlings can’t deal with it i’ll try stake cuttings. If that fails… lemongrass or vetiver grass, at least they are proven here.

    1. Hey Tarant,

      I’ve been very interested in Ecuador for a long time now, always looking for contacts in that part of the world. If you see this message and want to, please email me! I’d love to make another contact, and especially one who is currently working with these kinds of practices.

  2. Great summary of the swale story. I have recently been exposed to some very uplifting variant on this type of technique called Syntropic Agriculuture (or Agroforestry) Putting layered forests in place and planning production generationally by time and by height and by available light are the logical extension of this work. The technique takes companion planting to another level extracting only the yield.
    Thanks for the well written article.

    1. Hi Tony, I don’t know if you’ll see this but I’m really interested in where you learned about Syntrooic Agriculture. I’ve been ready Ernst Gotsch’s website but there isn’t much in English and Google Translste only goes so far …

  3. Just a silly note about this sort of thing from nearly a thousand years ago. Rabbi Shlomo ben Ytzhak known as Rashi was a vintner. One of his students wrote that Rashi would practically break his back each year in the spring carrying bucket loads of soil up the hills since the rich soil would be washed downhill in the winter. The plants were probably planted far apart so wouldn’t act like a hedge. Too bad this hedge idea wasn’t known then.

  4. This article is a good contribution to a multi-story topic, which often is only addressed as “swales are us”. I also have a small farm in Ecuador, and here in our 5th rainy season, we were inundated with heavy rains that have convinced me it is good to save space for swales and keep them available as an option. Providing a moderate slope of .5% grade (mas o menos), to guide excess water away, and help prevent terraces from sliding. Local culture strongly is in favor of ushering the water from heavy rains as directly as possible downhill. As a collective practice, this has caused some pretty drastic erosion, with streams turning into canyons that become very difficult to redirect and spread out. Rather, we are saying, slow the water, pool it, but always provide overflow. That is, always provide the water a way out for those times when volumes of water weight accumulate. Those are the times that has turned local opinion against small “barreras” , that is, small earthen dams. Careful design, provided skillfully in a good PDC, has the answer. We are on our 5th year of providing PDCs, with simultaneous translation of both Spanish and English. Our participants are selected so we have a good mix of local campesinos as well as Ecuadorean professionals both as participants and presenters.

    1. Thanks for your comment. Zia u mentioned .5% slope on a swale on contour. Do u ever alternate the swale angle to get water going left then right when heavy rains fall?

  5. I actually like my swales growing weeds, because it gives free chop and drop material, to feed the trees, planted on the berm. It’s not so much maintenance to us, than it is time spent fertilising the food bearing trees.

    The hedge idea is a good one, if you don’t have the manpower, money for equipment, or back strength to dig your own swales. Either technique will do, given the site specifics agree.

    Almost all our land is sloped though, so swales aren’t just a way of capturing water: they create walkways to traverse the slopes, and become land to grow nutrient accumulators, on. Otherwise, our land wouldn’t be very productive.

  6. Here in temperate Auckland (but trending to sub-tropical it seems) at a home garden scale I find swales an excellent source of mulch and entirely manageable. Swales are my source of water, drainage, pathing, certain crops and a lot of my mulch.

    A hedge line is interesting in that it slows wind so many airborne particulates drop out as they slow through the hedge. This can build soil over time you can definitely see it here on the lee side of a hedge facing prevailing winds. These prevailing winds do not come in on contour though…

    I guess it’s all contextual. Makes perfect sense to transition swales to hedging where the swales are a hassle to maintain. But the hedges trapping water like a swale would?

    Very interested in how this water capture occurs.

  7. But swales are “tree-growing systems” as Geoff reminds. So tree will grow on the mound. Isn’t it the answer?

  8. Try CLUMPING bamboo – the shoots can either be allowed to grow parallel to the swale (increasing the size of the hedge), or eaten (if they are growing in the “wrong” direction). Additionally, the roots will hold the soil, and the older canes have a variety of uses in the garden.

  9. Adding to the study of this topic. “Keyline” contouring is useful for smoothly undulating farms etc . Briefly the start point is the point in a valley where the steepness changes. The enhancement to swale or contour design seems to be to not only hold water in the land, but to redistribute evenly to include ridges from the valleys, or in to dams. . The property where it was developed in Australia is in an undulating foothills setting.

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