HOW TO BUILD SWALES - and harvest water

[Music] g'day welcome back to the weedy garden a year has gone by since i started my garden here on the hill far away from any town and even further from a city i've learned a lot in 12 months i'm really beginning to understand how the soil is like the stomach for each and every plant that grows on this earth i've seen some plants thrive i've also seen some die but with each step with each wheelbarrow full of soil that i create here in my garden i get closer and closer to that somewhat secret life of plants i'm continuing the grounding experiments on building a worm farm in an old bathtub and i'm cultivating seedlings of fruit trees which will become a food forest the big news of course is that i'm studying permaculture i'm learning how to observe patterns looking deeper into cycles of life and nature so i can nurture this little weedy patch that i call paradise and share their knowledge with you it's easy because it's online it's mostly videos so i can sit back and watch listen and learn as long as i have my computer turned on and really it's about reversing the damage in this next series of three videos i'm going to share my swale journey which started with my own words what's a swale when i was first introduced to permaculture back in december last year when i met jeff lawton to give you all the info from the start jeff has allowed me to share this first video it's taken from the online permaculture design certificate course which i'm doing at the moment next week i'll post the second video i made while jeff was here in the in the weedy garden showing me hands on how to dig a swale for this garden and do it right on the third and final video in this whale series i'll show you how i built a swale for my food forest weedy garden style i'm really honored to be able to share the journey with you by the end of this little video series on swales you you'll be able to harvest and utilize water wherever you live in the world welcome to the swale series and now i'll hand you over to jeff okay let's have a look at swales swales are long level excavations that come in many forms and widths they can be just small ridges in gardens or rock piles across a slope or excavated hollows in flat lands and low slope landscapes they're not elements that fit into steep landscape like soil conditioners swells loosen soils and absorb water storing it in the soils and the sediments they intercept sheep flow and let it infiltrate recharging the groundwater overland flow is interrupted for a few hours or a few days and then infiltration becomes regularly downwards water moving at right angle the condor down towards the ground waters as a recharge into the soils and assisted by the tree roots trees are essential as components of swale systems so most of the time are swales on slope they're a mound excavated out from the trench to the mound and our topsoil is increased at the mount and it's loose most of the time we're planting trees up on the mound here and just below in deserts we may plant inside because we've got less rainfall and it's hard to drown the trees in the desert so you may move inside but the infiltration of water is at right angle of contour and it plumes away as it sits here and then soaks in we also plant the back slope often leguminous trees on the back slope here fixing nitrogen and the roots here help the absorption so the roots grow quickly chasing the water as it goes down slowly soaking in swells without trees risk water logging and local rainfall deficit because of the lack of evapotranspiration and the potential of too much water storage because they're on contour interrupts in the sheep flow they stop all the water moving past just temporarily and then just soak it in that water disappears into the soil the trees take some of that back and transpire it to the atmosphere tree planting must accompany swells in all areas so swales i like to say are tree growing systems and it's of most utmost important in deserts where there's so much rain that's needed so there's a chance that as you interrupt the flows of rain that come so infrequently and often in large events you can stop it soak it grow trees that transpire more water to the cloud base because the chances can increase the rainfall it will definitely increase the condensation in deserts the potential crayon spread of the fringe in trees so as the trees grow the crown spread from one side to the other shading the swale this is what we need to understand the width of the swell can be governed by the crown spread that will shade us well further reducing water loss to evaporation and dissolve in salt concentration and water loss because this water won't evaporate it'll soak now the back slopes and the inside trenches the swells can be grazed it's possible to run animals in here and put temporary fences up and graze animals on the back slope up to the inside of the mound eventually it won't make any difference but grass in this well won't have the same effect as the trees grazing between the back slope and the hangover forage from the swell trees can be quite beneficial because the maneuvering here in the swale when it rains dilutes right the way along the swale you get an even dilution of manure all the way along and that's soaking in but you can't expect grasses and herbaceous growth to have anywhere near the same evapotranspiration to the cloud base you've got to have the trees with the deep tap roots to increase that absorption swells can be wildly widely used across the climates dry land areas they can be very large because you've got to stop as much rain as you can when it comes in those large events and soak it in and get through most of the year reassuring your landscape of trees tree growth giving you shade tree growth stopping evaporation from wind they also of course work in humid tropics and humid cooled or cold climates and the hydration of the swell builds over about seven years each year year one year two year three year four it gets up to about year seven and you've got the maximum rehydration plume where each time it rains it comes a bit more and then you get to a maximum and it will fully hydrate to the maximum size and then quickly drop off the bottom they'll be recharge the maximum recharge to the ground water so you have a dampened hydrology that wets up as quickly as possible water available from wet season to dry season it's it doesn't matter that it rains in winter and you'll grow in season is in summer because it extends over one season and the roots reach their maximum influence at about seven years so the roots of the trees are coming down and they're increasing the infiltration effect essentially swales are always perfectly dead level with no water flow so water sits passively rises like a tide and then soaks in they're not compacted and they're not sealed they're made to soak they're uncompacted swell widths and swell deaths can vary in relation to the size of a property small properties small swells of course large properties can be quite large slope can make a difference the speed of infiltration on local soil types shallower wider swells in sands and narrower deeper swales often in clay fraction soils and after one or two good soaking rains you can seed and plant your swale to trees on both banks because you've got a certain amount of soak on both sides capillary action will take the water out to the back slope and on down and it will take a few years to over shade this whale base and accumulate humorous relief drop there will be a certain amount of leaves coming in an accumulation of humus but there will be atrophies a lot of leaf drop from the actual trees and as efficiency increases extra water can be led in so you can lead in diversion drains from country picking up water from hard services over land flow extra water enabling planting of high value trees so you can bring in different trees as the swale starts to function better and better you can increase the quality of trees and and the swell itself can handle more and more water over time so that enables you to move the system up advance it in quality that's what they're all about advancing the quality of the system swales can be a great benefit with hard service runoff in towns particularly sub-humid and arid towns could reduce the costs of the efficiency of stormwater runoff soaking the water into tree growth tree growth that could produce fuel mulch food products even fire proof tans all roof water and roof water tank overflows grey water waste could be led to swells and it doesn't really matter if swells are in sand or in clay in sand or even cinder ash they grow trees initially pioneer trees that slow and absorb and hold water for longer and once established high value trees can then be planted and swells the opposite end of the scale in heavy clays work well initially growing pioneer trees with roots that penetrate the clay breaking it up and increasing the absorption so it's not the material that you're swallowing through it's the pioneer trees that you might have to go to in sand as you're planning initially or in clay the different types of pioneer trees that actually favor the different extremes of material and then as the conditions change as you improve the absorption as you improve the fertility then you move into high quality trees we know that this works the trees grow faster and are healthier on runoff fed swells than trees planted in open country in arid areas it's most important we plant trees on swales or salt concentration may occur downhill and collapse soils so we know the trees are pumping the water cycle and stopping the concentrations of salts swells are just temporary events really over the long period of time they're replaced by trees trees take over the function they are the precursors to the rehabilitation of forests in a region and they give us that convenient contour lineage to work with the base of a swale when we look at the base of a swale it can be ripped to increase absorption it could be graveled so we can gravel the base with swell or it could be sanded and on small swells it can even be mulched so you can deep mulch as well in a small swell in a garden you won't have enough material for a large swell or you can put down gypsum to loosen clay if you're in heavy clay soils to allow more in water infiltration the spoil of the swale is normally mounded downhill so our top source there the excavation has come over to our mound but in flat country there might not be amount because in flat country we'll spread the material out on the lower side usually but it won't look like there's a mound at all so you'll get a flat profile of a swell and the distance between swells changes to country on hill country the potential vertical height of the trees at maturity projected horizontally to the hill as a maximum density that's an average sort of approach so as a hill comes down and it changes in steepness where we have our swales the height of the trees projected back the potential height of the trees comes back each time and that's the maximum amount of swells we need so as we go on to the steeper country that projected height makes the swells closer together as we get on the steep it's closer as we go shallow it's further apart but when we look down from the bottom of the hill when we look up all we can see is canopy it looks like the whole landscape is forested but there's lots of interswell there because these are actual lines of trees there's a group of trees in that line but that's just a rough gauge there's no exact about this it can change to country another way to gauge distance is three to twenty times the average swell width depending on rainfall most useful average size swale bases are around one to two meters and the indus whale space three to 18 meters but there's no absolute average it's more likely that the closer space in in rainfall that's quite large say 120 centimeters 50 inches and wider spacing in rainfall of light small ranges of 10 inches 25 centimeters or less in humid areas the interswell is usually fully planted with hardy species and many of them as mulch producing species in dry areas maybe it's quite bare and mainly functioning as runoff for the swells themselves but mulch will blow into swells and wash into swells as as water flows it'll bring organic matter in organic matter will arrive in swales and find dust and silts build up in the swale bases they become deposition systems they're collecting all kinds of detritus material that in itself is increasing fertility they naturally actually build soils and over a period of time they will start to fill up and become level terraces over a very long period but by then you've got a very large forest there you don't need to swell or you can cast sidecast the material out onto the mound and increase the amount you can actually keep redressing it doesn't matter you can even put domestic waste and organic matter into a swell in buried pits you can bury pits in a swell this is like swale furniture swale attachments these will fill up with water and they will become rich soil deposits inside a swell either in the mound or in the trench itself and on windy sites this whale spoil bank this swale bank it's actually a very sheltered starting place for plants and trees and every six to ten swell can be planted to a wind break where wind is the limiting factor you can use the swales themselves as wind breaks wells and the swells in between is production swells so they go into another function and we know ridges should always have wind breaks because ridges are out there in the wind but also there's more condensation on ridges and that condensation is a trickle down moisture with nutrient and if it's swelling downhill we're picking that up and spreading it out swell sections can be over deepened as well so there are places where we can put in deep sections and this is most effective in clay fraction source creating kind of ephemeral ponds where if we're in sands we can often go into widening for more effect and in volcanic fraction soils which are like sands as well very absorbent there we can create soak pans that readily absorb water and increase the groundwater recharge swales can be kept to a convenient witch so they can be a foot track or they could be a wheelbarrow track in a garden or they could be on a small property a quad bike track or they could be a tractor track on a large property they can be used for transporting supplies in and produce out and many different functions for as well you need to get along as well to get material in to mulch to compost to fertilize to water possibly in really dry periods you might want to flood a swell if you've got dams uphill and you need to get product out they're a convenient way to get across country because they're perfectly level we are continuously surprised at the performance and function achieved by swales [Music] thanks for today and thanks for watching i'm going to go and have a bath now you

Channel: The Weedy Garden

Views: 602,037

Keywords: swales, permaculture, geoff lawton, organic gardening, how to garden, how to make a food forest, growing your own food, sustainable living, off the grid, grow food, gardening, water, harvest water, gardening tips, water catchment, sustainability, vegetable garden, covid garden, lockdown garden, covid project, lockdown project, planting fruit trees

Id: Rz6i5I42JmM

Length: 22min 58sec (1378 seconds)

Published: Fri Apr 23 2021