What Are Swales: A Quick Guide for Home Gardeners

Swales are one of the most popular concepts in Permaculture and one of the most misunderstood and controversial.

• Some say that they are ineffective and don’t work.
• Others argue that they only apply to specific climates and conditions, while having negative effects everywhere else.
• Some groups claim that you damage the environment by changing the landscape when you shape the earth to implement them, and even say that they are a colonial tool.

The truth is that they are a core tool for building abundance - including in your backyard.

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In this edition, in 4 minutes or less:

#1 What are swales - the true story

#2 When they are not an abundance building tool

#3 You can apply swales in your home garden and gain their benefits

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What are swales - the true story

Swales are multifunctional permeable ditches on contour. They occur naturally in nature through the effects of water, wind, gravity, and animal activity moving earth in the process.

They function as:

• Tree planting systems
• Rainwater catchment systems
• Irrigation systems
• Access infrastructure
• Transportation of materials
• Harvest assistance
• Soil conditioning systems
• Safety systems
• Prevent water erosion
• Prevent fire damage
• Can be converted to chinampas (water channels) if:
• Made impermeable
• Or where precipitation exceeds evaporation, because water remains there

If we leave nature alone, a site will progress until it becomes a forest with diverse tree species, rich ground cover, abundant insects and animals, excellent rainwater retention and infiltration capacity (while preventing water erosion), and some of the highest quality fertile soil. But that happens “by nature’s will,” or rather, without adapting to our schedule. We can build swales and create a time stack where 100 years of spontaneous biological development can occur in just a couple of years.

This can even apply to your backyard, as mentioned before.

When they are not an abundance building tool

Above all, we should not apply them to untouched nature. Bill Mollison, the father of Permaculture, warns us that we should always focus on conserving nature, because forests are the anchor of our biosphere and an infinite source for innovation.

Other reasons include:

• Safety concerns: If placed without proper safety measures, like adequate spillways, they create death risks. In this situation, a poorly built swale can cause flooding and/or landslides.
• Poor planning: If placed without considering the Whole Site (Garden) Design (check out our letter series), also called the Mainframe Design. This is the design process where you examine your space to determine where and how to place garden elements so that your garden simply works. If you place something important in the wrong location, your only lasting solution will be to retrofit your garden - which takes considerable time and money.
• Inappropriate application: If you place a swale even though it doesn’t make sense in your design - you’re just following the ‘shiny object syndrome.’ This could be in a place where you already have more than enough water, or where precipitation exceeds evaporation. Swales in these situations can be tools to pacify water or can be allowed to fill up, becoming chinampas.

Some people argue that changing the landscape - an element high on the scale of permanence - by building swales is harmful to the environment. They are correct when considering untouched nature. What they don’t understand is that Permaculture Design suggests conserving preserved sites and intervening in previously used places to render them productive and sustainable, so that we can further increase conserved forest areas. (Paul Stamets shares in his book “Mycelium Running” on pages 70-71 how old growth forests have untapped economic, medicinal, and depollution potential if left untouched.)

Swales are an abundance tool when we don’t use them to destroy nature or create avoidable dangers.

You can apply swales in your home garden and gain their benefits

So, you are allowed to place swales in your garden because you are making the site more productive, building soil, producing food, reducing your workload, creating a microbiome for many species (including humans), and enjoying your gardening hobby.

Swales excel at soaking water into soil and growing trees. I recommend:

1. Place one swale at the top of your garden, where incoming rainwater enters

At the mound of the swale, plant some perennial species that don’t cast shadows on your garden and are useful. They might produce food, or they might flower, attracting pollinators and beautifying your space.

You’ll be stabilizing that edge, preventing grass or “weeds” from entering your garden.

2. Place one swale at the bottom, right before water leaves your garden

Plant another perennial at the mound of the swale. If it won’t cast shadows on your garden, consider planting a tree. There are also dwarf tree varieties (if you don’t know which tree, check out this letter). It will have many positive effects on your garden, including creating a favorable microclimate, attracting pollinators and predators, and yielding what the tree produces plus organic matter that you can compost.

Before moving on:

Where shadows are cast in your garden in relation to swale positioning depends on your location.

You might get shadows in the opposite direction than I described, or shadows may lie parallel or at an angle to your garden. You might also want some areas of your garden shaded, so cast shadows might be advantageous.

Design it beforehand (with Whole Garden Design).

3. Make your garden pathways on contour, so they become swales

This way you can soak rainwater directly into your beds. You’ll also have more efficient pathways because, since they’re level (on contour), it’s easier to move things around. Fill your pathways with wood chips and inoculate them with mycelium to have beneficial fungi in your garden.

To finish, mulch your beds.

4. Install diversion pipes or channels to redistribute water along your new swale system

You also need to install spillways for safety reasons, which will be our next edition and part 3 of the ‘Strategic Water Reserve for Any Garden Endeavor’ letter series (Part 1 and Part 2).

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The only reason not to consider swales is if the site is untouched forest - we should conserve it by leaving it alone.

• In all other places already modified by previous human activity, we are allowed to apply design.
• Swales excel at broad-scale applications, building multifunctional elements to control and gather water, create efficient site access, and plant trees.
• Nevertheless, they can be applied with the same positive impact in backyards, creating abundant and aesthetic home gardens.

Do swales look like bad design?

See you next Tuesday!

Alexandre and Marina

P.S.: Does this kind of garden design look preposterous?

If you don’t think so, check out our guide on how to transform your vegetable beds with Permaculture.

Sources: Mollison, Bill, Remi M. Slay, Jeeves, Andrew. Permaculture A Designers’ Manual. Tagari Publications, 1988, p. 167 Figure 7.23

Stamets, Paul. Mycelium Running: How Mushrooms Can Help Save the World. Ten Speed Press, 2005, Chapter 6: Mycoforestry.