DESIGNING SWALES - Geoff Lawton visits The Weedy Garden - Swales Part Two.

Summary

In this educational video, the host invites Jeff to demonstrate the creation of a swale in a garden setting. They discuss the purpose of swales in water management and nutrient distribution, emphasizing their importance in permaculture. The step-by-step process of marking, digging, and planning the swale is shown, including tips for ensuring water retention and tree placement. The video also touches on the ecological benefits of swales, such as supporting frog habitats, and ends with a call to support the host's Patreon for more in-depth content.

Takeaways

• 🌳 Building a swale helps in managing water flow, spreading, soaking, and sharing nutrients across the landscape.
• 🚜 Jeff demonstrates the hands-on process of creating a swale, emphasizing the importance of getting it right the first time.
• 🪓 The best footpath is located right down the middle of the ridge, ensuring even water distribution.
• 🌿 Swales are essential for tree growth systems, as they enhance moisture retention and nutrient distribution.
• 🌱 Acacia trees serve as green manure in the landscape, fertilizing the soil but dying when their job is done.
• 🌾 The back cut of a swale should be stable, with a gentle slope to prevent erosion and falling apart.
• 🍃 Planning space is important for where the water will sit and how it will spread across the garden.
• 🚶‍♂️ Swales should be designed for practical use, such as making sure wheelbarrows can easily navigate them.
• 🌧️ Overflow points should be carefully planned to ensure no erosion and proper water distribution to other swales.
• 🐸 Shallow swales create habitats for frogs, adding ecological benefits to the garden.

Q & A

What is the main purpose of building a swale in the garden as described in the script?

The main purpose of building a swale is to interrupt the water flow running off the property, spread it, and soak it into the soil to share nutrients throughout the system. This helps in growing food and retaining moisture in the landscape.

What is the significance of the ridgeline in the context of swale construction?

The ridgeline is significant because it is the next most stable to contour tracks, and it helps in directing the water flow evenly from the footpath, which is essential for the swale's effectiveness in water and nutrient distribution.

Why is it important to avoid disturbing the ground at the overflow point of the swale?

It is important to avoid disturbing the ground at the overflow point to maintain a stable and erosion-free area. Keeping the grass mowed like a lawn ensures a nice even stream of water without causing any erosion.

What is the role of the a-frame in the process of building a swale?

The a-frame is used for surveying and marking the location where the swale will be dug. It helps in ensuring that the swale is built on the correct contour and at the right depth to effectively capture and distribute water.

How does the swale design benefit fruit trees, such as the mango tree mentioned in the script?

The swale design benefits fruit trees by providing them with a source of water and nutrients. The water from the swale soaks around the tree, enhancing the soil and providing the tree with the necessary moisture and nutrients for growth.

What is the purpose of the 'level seal' in the swale construction?

The purpose of the level seal is to control the height of the water in the swale. It ensures that the water overflows at a specific point, preventing the water from running off the property and instead spreading it across the landscape.

Why is it recommended to walk along the marked line before digging the swale?

Walking along the marked line before digging helps in visualizing and feeling the swale's layout. It allows for adjustments and ensures that the swale is comfortable and practical for use, such as moving a wheelbarrow along it.

What is the importance of decompacting the soil before building the swale?

Decompacting the soil is important because it allows for better water absorption and root penetration. It prepares the soil for the swale by ensuring that the water and nutrients can be effectively distributed and utilized by the plants.

How does the swale contribute to the overall permaculture design of the garden?

The swale contributes to the permaculture design by integrating water management and nutrient cycling into the landscape. It helps in creating a self-sustaining system where water and nutrients are efficiently used to support plant growth.

What is the role of green manure in the swale system as mentioned in the script?

Green manure, such as the acacia mentioned in the script, plays a crucial role in fertilizing the landscape. These plants are allowed to grow and then decompose, adding nutrients to the soil and enriching the swale system.

What is the significance of the 'back cut' in the swale design?

The back cut is significant as it provides stability to the swale. It should not be too steep to prevent soil from falling in due to clay swelling and shrinking in different weather conditions. A stable back cut ensures the longevity and effectiveness of the swale.

Outlines

00:00

🌱 Introduction to Building a Swale

This paragraph introduces the concept of building a swale in a garden to manage water flow and improve soil fertility. The speaker invites Jeff to demonstrate the process, emphasizing the importance of doing it right the first time. The video aims to provide a hands-on demonstration of constructing a swale, which involves creating a level footpath that directs water evenly from the footpath to the surrounding area, including fruit trees. The speaker also mentions the use of an A-frame for surveying and planning the swale's location.

05:02

🔨 Practical Steps in Swale Construction

The paragraph details the practical steps involved in constructing a swale, including the use of pegs and an A-frame for marking and leveling. It discusses the importance of decompacting the soil and the strategic placement of the swale to capture and utilize runoff water effectively. The speaker also touches on the role of green manure trees like Acacia melanoxylon in the landscape and their purpose in fertilizing the soil. The process of digging and preparing the swale is described, highlighting the need for a comfortable width to accommodate a wheelbarrow for ease of transportation.

10:12

💧 Water Management and Soil Preparation

This section focuses on the water management aspect of swale construction. It explains how the swale is designed to capture and retain water, allowing it to soak into the soil and enrich it with nutrients. The speaker describes the process of creating a soft mound in the swale filled with a mix of topsoil, weeds, and grass to facilitate water absorption and root penetration for nearby trees. The importance of the back cut for stability and the level seal to control water height are also discussed, along with the strategic placement of trees to benefit from the enhanced moisture in the subsoil.

15:12

🌳 The Benefits of Swales for Tree Growth and Water Retention

The final paragraph emphasizes the benefits of swales for tree growth and overall water retention in the landscape. It describes how the swale enhances the area for tree roots, providing them with access to water and nutrients. The speaker also talks about the importance of creating a level seal to ensure water overflows in a controlled manner, preventing erosion. The paragraph concludes with a creative idea of using a rubber duck to demonstrate the swale's water flow and mentions the speaker's Patreon page for additional content, inviting viewers to support and explore more behind-the-scenes videos from the garden.

Keywords

💡Swale

A swale is a shallow, broad, and long depression in the ground designed to capture and slow the flow of water, enhancing infiltration and distribution of nutrients. In the video, swales are the central theme as they are being constructed to manage water flow and support fruit trees, illustrating the concept of water harvesting in permaculture.

💡Permaculture

Permaculture is a system of agricultural and social design principles that aim to create sustainable and self-sufficient habitats mimicking natural ecosystems. The video demonstrates key permaculture practices such as swale construction and the use of green manure, showcasing the integration of these concepts in garden design.

💡Water Harvesting

Water harvesting refers to the collection, storage, and management of rainwater or runoff to be used in agriculture or other purposes. The video's focus on swale construction is a practical example of water harvesting, emphasizing the importance of capturing and utilizing water efficiently in a garden setting.

💡Ridgeline

A ridgeline in the context of the video refers to the top of a ridge or hill, which is an important feature in the landscape for planning the placement of swales. The script mentions using the ridgeline to determine the path of the swale to ensure even water distribution and to prevent runoff from leaving the property.

💡Contour

Contour lines or paths follow the natural shape of the land, and in the context of the video, contour swales are designed to run parallel to these lines to slow down water flow and increase its absorption into the soil. The video explains the importance of building swales on contour to maximize water retention and nutrient distribution.

💡Green Manure

Green manure is plant material, such as the acacia mentioned in the video, that is used to improve soil fertility by adding organic matter and nutrients. The video discusses the role of certain trees as green manure, emphasizing their purpose to fertilize the landscape and eventually die once their job is done.

💡Decompaction

Decompaction is the process of breaking up compacted soil to improve its structure and water infiltration. In the video, the host discusses decompacting the soil before adding a layer of topsoil to the swale, which helps in creating a better environment for water absorption and root growth.

💡Level Seal

A level seal in the context of swale construction is a technique used to control the height of water in the swale and direct overflow to the next swale. The video describes creating a level seal by marking a certain height with mud and ensuring the water overflows in a controlled manner, preventing erosion.

💡Mound

In the video, a mound refers to the raised area of soil within the swale that is designed to hold water and allow it to soak into the ground. The mound is created by decompacting the soil and adding a layer of topsoil, which also serves to double the amount of topsoil in that section, benefiting the trees.

💡Overflow

Overflow in the video refers to the excess water that flows out of one swale and into another, ensuring efficient use of water resources and preventing runoff. The script discusses managing overflow through the use of level seals and pipe crossings to maintain water distribution across the garden.

💡Fruit Trees

Fruit trees are an integral part of the garden's ecosystem in the video, benefiting from the water and nutrient distribution provided by the swales. The script mentions specific fruit trees like mango and how the swale system is designed to enhance their growth by providing water and nutrients directly to their roots.

Highlights

Introduction to the concept of a swale and its importance in garden design.

Jeff demonstrates hands-on how to start a swale in the garden.

Explanation of the benefits of building a swale for water and nutrient management.

The selection of the right location for a swale based on the ridgeline and footpath.

Strategic planning for water flow and swale placement to maximize garden productivity.

The use of an A-frame for surveying and marking the swale's path.

Importance of balancing the swale to avoid overshadowing fruit trees like mangoes.

Techniques for decompacting soil to prepare for swale construction.

The role of swales in capturing overflow and directing water to fruit trees.

Discussion on the benefits of swales for moisture retention and garden footpaths.

Jeff's experience learning the importance of swales from his teacher Bill Mollison.

The function of trees as green manure in the landscape and their role in fertilization.

Instructions on how to properly size and shape the swale for optimal water retention.

The concept of a level seal and its role in controlling water overflow in swales.

The importance of maintaining a stable back cut to prevent soil erosion.

Strategies for marking and measuring water levels in the swale for even distribution.

The long-term benefits of swales for tree growth and soil health in the garden.

The role of swales in creating a sustainable and self-fertilizing garden ecosystem.

Invitation to support the creator on Patreon for additional content and insights.

Transcripts

[Music]

g'day and welcome back to the weedy

garden

by now you should have a really good

idea of what a smile is

so i called jeff up the other day and i

asked him if you'd like to come out to

my garden and demonstrate

i bet you know what he said yeah he said

i'd love to

so here he comes up the hill it's a

lovely day

today to start a swale i reckon because

i was trying to listen and learn

i didn't put the full weedy garden

photography department magic on this

video

i'm saving it for the last and the final

video on this swale series

which will be coming out about this time

next week

so building us whale is easy you just

got to get it right the first time

and here's jeff again to give a hands-on

demonstration

welcome to part two of the swale series

so i need a hammer and a medic

i can use the back of an axe i'll have

to

i know which side's the right one

because your your best footpath here

is kind of like there right down the

middle of the ridge going to that

big post because then the water goes off

evenly from the footpath it's

you know ridgeline tracks are the next

most stable to contour tracks

so for you to get over the swell or get

past the end of it

you either overflow here or you put a

pipe cross in and continue to swirl

around to where it finishes and this

is a little pipe crossing footpath so

you're coming over here with your

wheelbarrow

and then you're coming down to your next

one there's another way we could do this

and let's start from the extremity of

the ridge

yeah because that's

the longest swell on this patch

is that ridgeline

but you're walking straight down any

overflow is going to get caught by these

swales

and spread and soaked into fruit trees

it's all going to get to the creek in

the end but on the way it's going to

grow our food

yeah i'm just gonna get the uh uh the

a-frame and see where i go from here

just seeing whether we missed that mango

if we missed that mango we're right

yeah yeah

yeah we want it just to be nicely

balanced i could slightly

wobble back forwards but that'll do

i'm just doing a rough well water or

level it later

we'll miss that mango that's the main

thing we will miss that mango is that

good or bad

oh it won't really matter to the mango

it's a big tree

well it's going to benefit from the

swell water but generally the water is

going to soak all around here

and i'm i'm surveying here with this

a-frame

where i'm going to dig back into the

hill so it's just going to be sitting on

the back of the swale

and there'll be a whole load of fruit

trees on this side mango's like a dry

period and we're in a very humid

landscape

so it doesn't matter that's just on the

top side uh there'll be stuff

underneath the mango you'll probably

have coffee and and

five corner fruit carambola brazil chair

other things will grow

under this giant mango over time and

they won't be as productive in the sun

but they'll take up the space

and you'll be walking along this whale

with your wheelbarrow full of mangoes

all the way around on a nice level so it

needs to be level because it'd be such a

big mango

you know wheelbarrow full of mangoes i

wouldn't want you going up daniel

[Music]

oh yeah right so we're going to miss

this mango

we're going to go just below it which

will fit in really nice with that giant

tree

and the mango tree is looking really

nice it's going to have a lot of

nutrient because i know that mango's got

nutrient underneath it

and that's going to be draining into

this whale and it won't be just running

down the ridge

it'll be going all the way around the

garden

so why do you build swales yeah well we

build swells to

interrupt the water flow that's running

off the property

to spread it and soak it and share the

nutrient through the system

now we can place our nutrient

above the swell and

any water flow that starts to run on the

landscape

we know it's running at right angle to

contour

the swell runs exactly on contour stops

it

spreads it soaks it with the nutrient

that we actually position

the swell to receive how many more of

those pegs you got

can i get some more yeah

you might want to you might want to

time-lapse me putting these in

[Music]

thanks for doing all the hard work yeah

it's all right

it's probably all there anything i'm

really good at

might be a little bit of root zone going

around this uh acacia

do you reckon i should chop it out um

you're probably going to kill it with

kindness anyway

well you'll shorten its lifespan because

the job will be done these trees are

the green manure in the landscape so

their job is to fertilize

that's actually the fertilizing green

manure of the landscape acacia

melanoxylon

so if it's if it gets too fertile it's

going to die because it's job's done

um my teacher bill mollison yeah

and uh i didn't really pick it up

as clearly as i should on my

permaculture design course but when i

went to visit his property he he's

putting swells all over the place

and then i got to realize how important

they were you can use swale

type design in gardens as garden

footpaths and

moisture retention but the definitive

swale is a tree growing system

you can have vegetables in there for a

little while while there's enough sun

yeah when i've drawn the line i'm

literally drawing on the landscape here

so when i've pegged like this i don't

just jump in i just

walk it i walk along it see what it

feels like

see what it looks like yeah it feels

kind of nice

you could put you could put three but

it's getting to be a bit

crammed you definitely couldn't put four

it's not to look like terraces

and that's not the idea

[Music]

i think two more would be nice you're

looking at something that's going to be

permanent so you want to get it right

i like this one definitely need this one

ridge line position

lowest point on the ridge line defines

that line

and picks up all the nutrient of the

garden just about all the nutrients

right on the middle of the ridge because

that that spreads the water

away from the overflow point dissipating

the energy

now the idea is it's got to be picked up

on this whale we're about to put in

so we don't let the water go or the

nutrient we use it again we spread it

and soak it

i'm going to put the soil on top of

there so i want it

de-compacted first so i'm going to start

digging

and i'm going to just do a little bit of

de-compaction here

i'm just going to prize here

all i want to do is prise it up a bit

relieve any compaction

i'm just going to move over this section

you can hear it ripping

so i want to be able to get a

wheelbarrow inside this whale

and comfortably pull it down flat

so this is the height that i this is the

width i want

and that gives me an uh

an idea of how wide this whale's gonna

be

so the bottom of the swell is gonna be

as wide as that wheelbarrow

i know it's going to be that wide

now i need to go down

you haven't got a little spirit level

have you we do

yeah we might use a little spirit level

in a minute

this is going to take you a while to dig

all my swales okay

yeah i reckon i only do about five

meters a morning

before breakfast that's my usual system

with little swirls

yeah lion's got a good breakfast ready

for me

yeah i need beef bacon eggs and tomatoes

if you haven't got the beef bacon i'll

bring it

it's not it's not the only thing you

need to do

so let's just size this up

here's our wheelbarrow and our

wheelbarrow needs to sit in there

it sits down there that the legs of the

wheelbarrow sit in there comfortably a

little bit of leeway

so when we're coming around with our

wheelbarrow full of compost

mulch or coming back with our

wheelbarrow full of mangoes

it's going to be nice and level right so

we've got a nice level

this is our base here and on my spirit

level

it's more or less level water will level

the rest of it

so that's our base now the water comes

in

and goes through this soft man that's

soft look look

look it's soft bitters bit of topsoil

in there and all the weeds and grass is

all mixed together we've got a nice

smooth mound

the water is going to sit on here and

it's going to soak in that way

a right angle to contour it's not going

to soak in there much can soak in here

and go into the subsoil that i i

decompacted

the top soil originally and then put

this top soil on top so i've weighed

that much topsoil

originally which i decompacted now we've

got that much so now we've got that much

topsoil from there

to the base we've doubled our topsoil in

this section

that's good news for trees they can go

through this soft mound

with the water going in under their

roots and they can go through the

decompacted

subsoil all that grass on the bottom is

going to die and all the vegetation

above the surface that was above the

surface and all their roots are going to

be compost corridors in the soil

tree roots are going to follow them

through if you

really want to know where you'd like

the water on your trees and you thought

about it

so i'd like the water right at the roots

of my trees and that's where it's going

to go

right through the roots of the trees now

this mound is nice and soft

it's got a gentle bank and it's got a

gentle bank

all of this is great planning space just

to where the water is going to sit which

is i predict the water's going to sit

about there

that depends where we set our spillway

and then from there

over the mound all the way down and

below is going to be enhanced for quite

a few meters

so that's the advantage of the swell

mound on the

upside this is what we call the back cut

now you can't leave it steep because the

clay in the soil will swell up and

shrink

in different weather conditions and

start to fall in you

want at least one to one and a half

slope on most soils

if it's unstable so even shallower

so as you get in the steep country with

the one and a half to one slope you're

going to have more back cut

because you're in steeper country you're

going to have more

angle to lay back it'll be the same

angle but it will go further because the

steepness of the slope

so as we go around in this whale the

other end down there

is steeper this is the security back cut

you don't want this being a mess you

don't want this falling apart

you want this stable back cut base

mound is plant the trees from where the

water sits

up over the mound down to the other side

and below

they're all enhanced so i think from

here

over premiere spot but also right down

here

you're still getting plumes of extra

moisture in the subsoil

yeah you want to hold a certain amount

of water in that swale right

so we could move up here and go from

there i want to hold that much

right so i could get my pen

now and mark that as a secondary mark

we're roughly level there right so we're

going to go

up about so high

all right so what we'd do is we'd mark

it like that with our bit of mud

can we see that mud yeah

so we want to come that high that's the

water we're going to have in our swale

yeah

we want this water to overflow

and pick up our next well we don't want

to go too far along there because it

gets steeper

so we're going to go along here

and we're going to go uphill

to the mud line right

and we're going to put another peg in

here it's going to be great when you see

this happen

and you put the water on and then we're

going to do that again on this one

yep okay

now we know right that is

about that much higher than the bottom

right we know it's

yeah we're going to sit that much water

in the swale so we bring our swale

up like this

so we've got a straight edge along here

we'll come up like that

and our swell trench is going to go

uphill and go

white out here and go back down again

and we're going to leave the mound off

here and that

will set the height of the water in the

swale so this is called a level seal

now here i don't want you to disturb

this ground i want you to keep that

that's an excuse for a little bit of

lawn

yeah so that you want a really accurate

cut there

a really accurate cut sharp edge and

leave this grass and keep mowing this

like a lawn and when the water gets up

to that height that we just measured

it'll come over here as a nice even

stream

no erosion ever none never never gone

out

ever never never no none whatsoever

so this will be an overflow point and

that water will go down there

and it'll hit that swell which will

block it from going off

and we're going to do it again so it

hits that last well

and this one up here is going to come

round from the weedy garden on that side

and have a little level so on this end

right near the

middle of the ridge and that's going to

level still over there

and one day you're going to do a movie

and you're going to take a little little

rubber duck boat or a little little

plastic duck and you're going to take

him down here over the level seal go and

hear down that one take him on the

journey down there

and count all the mangoes on the way for

our video by itself freestanding

just feed it up but the sand is fake

and another one you come out here and go

listen to the swells at night

very different from

because it's surprising they love

shallow swells

it's an orgy that's why they really

really can breathe shallow is what you

want

for a frog it's a disco man

and if you come out at one o'clock two

o'clock in the morning there's one last

frog

like the one drunk on the dance floor

you can't get the girl and it's just one

left out they're going wow

wow like once they get a root and finish

they stop

yeah they gradually go off as the night

goes on

they're rooted they've done it all

job done

see the little symbol down there it says

skip ad it doesn't work

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[Music]

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