She approached the workers and discussing the sad waste of water asked if they can direct the flow of water. They replied that they can direct it anywhere they like. So Roshani asked why they don’t  send it onto people’s property. They replied that most people would actually be quite upset because it would make a mess. Well we have swales, and that is exactly what they are made for. 3000 gallons and 7 minutes later the top swale completely filled and trickled over the level sill onto the next swale. This was a really cool thing to witness, as it would be quite unlikely for a rain event to match the speed at which the swale filled, well not without help from road runoff. Heres to being at the right place at the right time, turing a problem into a solution.

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El Manzano in Transition – Towards Community Resilience, by Design

by Grifen Hope of Ecoescuela El Manzano

1. PROJECT AIM
2. BACKGROUND
3. PROBLEM & LOCAL CONTEXT
4. OBJECTIVES & ACTIONS
5. NETWORKS
6. FINANCIAL INFORMATION

1. PROJECT AIM

The primary objective of this project is to assist devastated communities of Chile to plan and design their own resilient settlements, to quickly recover from the devastating Earthquake of February 27 2010, and to build long-term resistance to the future effects of natural disaster, economic, climate, and energy disruption.

This project presents a call for regional, national and international investment in living examples of good practice in the planning and design of resilient human settlements. Evidence of the outcomes from this approach will be used to influence regional and national government officials and policy makers to replicate the model throughout the affected regions of BìoBìo and Maule.

2. BACKGROUND

On February 27th 2010 Chile was hit by a ´Mega-earthquake´ that shook the very foundations of Chilean society. In total 4.2 million people have been affected, many of whom are still without basic public services. Approximately 1.5 million homes have been destroyed or heavily damaged, with an estimated 1 million people left homeless. Initial estimates suggest the recovery will cost US$30 billion and take 3-4 years.

On reflection it could have been much worse. While the quake was 500 times stronger than that in Haiti and devastation is enormous, Chile has fared relatively well. Compared to Haiti the death toll and damage to buildings and infrastructure has been moderate. With a long history of devastating earthquakes the Chilean government and people are well prepared to withstand, respond and recover from a large earthquake.

At this point in time the priority is still on the relief response and providing basic needs to hundreds of thousands of affected people. However, attention is now turning to planning for the reconstruction phase. I think some concise reference to the vulnarabilities of modern industrial systems to multiple likely future impacts of peak oil, climate change, etc. is warranted to explain why this local resilience approach is so important to advance, rather than using existing local national and international capacity to rebuild communities on the old pattern.

3. PROBLEM & LOCAL CONTEXT

The village of El Manzano, home to 28 families, is the first official Transition Town in Latin America and in a pre-earthquake process of redesigning itself for resilience to disaster. The village remains highly vulnerable to the systemic crises of natural disaster, economic, climate, and energy disruption. Many of the basic necessities such as water, food and medical care are dependent on external resources, and existing housing is not fit for human habitation. These poverty related issues have been compounded by the recent earthquake. As El Manzano is out of the main disaster area it is very low on the priority list for recovery. In response the community has identified its own vulnerabilities;

1. Dependence on electricity for water for drinking, irrigation of crops and animals.
2. Lack of access to land for subsistence crops, low fertility and low moisture holding capacity of existing soils, with dependence on unhealthy external food sources.
3. Earthquake damage to two houses making them uninhabitable, and a general state of substandard housing for the majority of village residents.
4. Reliance on septic tanks for household and human waste disposal, subsequent excessive use of water and contamination of shallow groundwater used for drinking.
5. Low participation in community activities and the design of a community plan for the development of local resilience.

4. OBJECTIVES & ACTIONS

The community of El Manzano has identified the following priorities for disaster response and recovery in coming months. These activities will provide practical training opportunities for local residents and permaculture trainees in construction of simple systems, and in regenerative design that can be replicated in other communities.

1. To ensure water supply for 28 families independent of the electricity grid for drinking and irrigation.
   (a). Implement appropriate solutions for the supply of gravity fed household drinking water and irrigation systems to generate resilience in drought times or black out.
   (b). Manufacture of PVC hand pumps for extraction of clean shallow groundwater.
   (c). Recovery of existing deep wells which can extract water without electricity.
2. To ensure local food security for 71 people by increasing natural fertility and water holding capacity of soil using locally available materials and recycling of organic wastes.
   (a). Establish 1.2 hectares of community garden to meet the vitamin and calorie needs of 71 residents.
   (b). Cultivate 1.9 hectares of community compost and grain crops for the food self-reliance of 71 people.
   (c). Implement a local food cooperative so residents can purchase bulk food in the village.
   (d). Development of soil improvement techniques and organic soil amendments.
3. To rebuild two houses made uninhabitable in the earthquake (affecting 2 families: 3 children, 3 women, 4 men) as a model for other residents to improve substandard housing conditions.
   (a). Rebuild the 40 m2 house of Don Oscar and family using locally available natural materials to be earthquake resistant.
4. To ensure appropriate sanitation for 28 families, reduce need for water and reduce groundwater contamination.
   (a). Reduce water consumption and contamination of ground water with construction of dry composting toilets.
   (b). Implementation of simple bio-filters for the safe re-use of grey water in gardens.
5. To support the community design process in EL Manzano and develop a Community Resilience Action Plan.
   (a). Provide a model of community-led planning and design for community that can be replicated widely in the affected regions of BíoBío and Maule, and around the world.
   (b). Disseminate the results widely to local and regional authorities to attract attention and replication in other affected communities of BíoBío and Maule.

5. NETWORKS

Ecoescuela El Manzano (EEM) is uniquely positioned to make a big difference in the reconstruction process. EEM has developed strong relationships with the El Manzano Neighbourhood Association and Youth Group, and assisted a core team to begin the Transition planning processes here. Relationships have been formed with the mayor and local council of Cabrero and their PRODESAL programme supporting rural women in small enterprise. A partnership has been formed with the regional demonstration centre Centre of Education and Technology (CET) Yumbel to share resources and expertise. EEM is working with the foundation Work for a Brother to duplicate the El Manzano project in some of the worst disaster affected communities on the coast of BíoBío. An existing contract with the Ministry for the Environment (MfE) through the Environmental Protection Fund exists to install appropriate technology during 2009 in a community demonstration centre, and in 2010 in all houses in the village. In 2009 El Manzano was recognised as an example of best practice in community development by national organisation Territorio Chile. At a national level Ecoescuela has been instrumental in forming the Instituto Chileno de Permacultura and training a network of 140 permaculture designers and teachers. At an international level Ecoescuela is a regional training centre for sustainability in partnership with the Permaculture Research Institute, Holmgren Design Services, Gaia University and the Transition Towns Network.

6. FINANCIAL INFORMATION

Ecoescuela El Manzano has committed to raise US$50,000 to augment an existing US$17,500 for this ambitious and important project in 2010.

A donation from you will help turn disaster into opportunity. Through redesign of damaged settlements we can alleviate emergency need, and invest in long term resilience.

Gracias from Chile!

advance to the worldwide permaculture community for getting behind this work. You never know – in the future you may be the recipient of such assistance.

Donate via PRI USA (USA residents)* Other non-paypal methods of donating here
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*Please be sure to click on the ‘Add special instructions to seller’ link, and then type ‘CHILE’ in the field provided, to ensure these fund are correctly diverted.

In classic permaculture style, within the problem lay the seeds of the solution. The deforestation due to conventional agriculture in these surrounding hills has caused soil erosion and during the rainy season much of this rich volcanic black top soil is washed downstream. This annual bounty has been redirected through the Ijatz site using a sequence of channels and sink holes, which in turn slows the water flow enabling the nutrient rich humus to be captured and stored on site. The earth has been moulded to create slopes, edges and contours essential for increased growing opportunity.

During the dry season any rainfall is held in the pond sequence, maintaining the local water table which is the source for the hundreds of trees and plants. While the flora perpetually contributes biomass to improve soil fertility, a micro climate suitable for growing has developed in what is essentially a few acres on the edge of town. Prior to the establishment of the Ijatz project, over one hundred homes were annually flooded in the immediate vicinity. Currently, the site can receive flood water to the depth of more than a metre during the wet season. A perfect demonstration of a multifunctional permaculture design element, the banana circle has provided the solution. Acting as a pump, that most excellent of pioneer species, the banana simply sucks up and holds this water. The spaces between the rubbery concentric rings of a banana tree are simply saturated in water. The centre of the circle becomes a compost heap for any site prunings while the worms of the vermicomposting stations make short shrift of sections of banana trunk. The composted output is another useful income stream for the coop. Of course, let us not forget nature’s own delicious potassium stick – the banana itself! All this and the local community benefits from dry homes throughout the rainy season too. This in turn satisfies one of the cornerstone ethics of permaculture: people care – positively affecting the local community.

Banana circle

The project is only thirteen years in the making and boasts a diverse range of trees and plants that reach every level of the canopy. Timber is harvested and the bamboo stands are about 6m tall. There are a number of guava, grapefruit, lime and lemon fruit trees. A vine layer producing a vegetable called güisquil (sechium edule) when boiled is similar in texture and taste to a tender swede or turnip. There are several other local tropical plants that contribute roots or leaves to the kitchen table. The annually deposited soil is then built up to form raised beds for growing vegetables. My three week stint centred around reinstating the vegetable and herb beds preparing them for fresh seedlings, including lettuce, coriander, frijoles (beans), parsley, celery and radish. This soil food web is teaming with life and I encountered countless worms, spiders and other small creatures. Thankfully, the nesting cobra we stumbled across only wrapped itself around Pancho’s arm (the head gardener). No harm done – sadly only true for Pancho!

The core focus of the Ijatz cooperative is coffee production. On the final day of my visit, the ladies of the cooperative harvested fifty kilos of coffee beans ready for processing. However, they collectively own several plots of land on the slopes of the now extinct Volcán Tolimán. Through the cooperative, the workers have generated a stable income which has funded educational programmes on child care and nutrition. They also have discussions to understand where their high value product sits in the open market. I was invited to describe the drinking habits of Europeans. My talk was graciously received even though my Spanish is woefully short of adequate.

If you are interested in volunteering your time and energy to the assist the Ijatz project and you have a command of Spanish language you can contact them directly at asociacionIjatz (at) gmail.com otherwise I can advise you. Volunteer opportunities exist throughout the year.

Read my follow up article about how Ijatz manages its core business – coffee, using permaculture principles. You can follow my blog at www.kevpermatour.blogspot.com as I travel Central America gaining permaculture experience working towards my Diploma in Applied Permaculture from the Permaculture Association Britain.

The village of Necpaly sits at 510 metres above sea level, on the eastern edge of the Necpalská Valley, in the Turiec region in the mountainous north of landlocked Slovakia. The area is filled with rolling hills and cascading valleys framed by mountain ranges peppered with deer, wild pig and bear. And, noteworthy for this particular article, the area boasts abundant flows of crystal clear water.

The village itself is ancient. Earliest written records/documents from Necpaly date back to the year 1266, but archeological evidence of habitation go back as far as the bronze age. I would describe the climate as cold temperate. The average annual temperature is 7.5°C and rainfall is around 830mm per year. Temperatures can reach as high as 42°C (108°F) in summer and as low as -25°C (-13°F) in winter. (As the climate warms the former, high temperatures are becoming increasingly common, and the latter lows almost not known any more.)

Entering the village of Necpaly

The other side of the turbine

I recently had opportunity to visit Necpaly to check out a micro hydro system that has been running there for three years now. The village has a population of around 850 people, with, I would guess, a little less than 200 houses. The turbine pictured at top has minimum/maximum generating capacities of 16 to 21 kWh, depending on seasonal water flow changes. This is enough power for more than twenty five houses, although its actual usage is a little more complicated, since instead of just feeding private residences the electricity powers street lights as well as the main community infrastructure buildings like the village hall, school, etc.

The micro hydro installation consists of a three hundred metre long diversion from the village stream, with the turbine situated part way along this man made channel. The diversion enables an artificially generated height advantage for increased head pressure, and runs for two hundred metres to create a four metre drop where the turbine sits, and then runs for another one hundred metres before it meets back up with the originating stream.

The intake for the diversion also has a few overflow spillway points to ensure the turbine doesn’t attract more water than it can handle. Excess water simply drops back down to the originating stream.

Part of the three hundred metre stream diversion

Where the diversion returns to its source there is an additional three metre drop where another, smaller, turbine could be installed. There is, in fact, a plan for two more smaller turbines to add to the success of the original.

The whole system is quite aesthetically laid out – with parts of it forming attractive water features for the village.

Most people looking at the turbine would intuitively assume the water powers the turbine from above. Instead, the turbine spins in an anticlockwise direction (if you’re facing it as per picture below).

The water drops four metres and is focussed through a smallish opening at
bottom of the boxed construction, forcing the water to rush upwards and fuel
the turbine from below

The installation cost €100,000 (US$140,000). Given its generating capacity alone, the system should pay for itself within ten years at the outside. But, it gets a little more attractive again in this instance, as excess generating capacity is sold back to electricity companies, in accordance with EU laws that require these companies to purchase excess renewable power. This is called a Feed-In Tariff, a mechanism that has had a lot of success in ramping up the uptake in renewables in Europe – Germany in particular, being the first European country to begin serious implementation of the system. This factor should decrease total payback time quite significantly.

The installation was financed by an EU subsidy as well as local shareholder investment in the project. Investors get a return by way of the above-mentioned sell-back of excess power as well as sale of base power to the villagers themselves.

Once established, maintenance for the system is low. Beyond the hardware connected to the turbine itself, winter and spring months bring leaves that need to be filtered out of the system, and the diversion itself can require a little patching to reduce leakage.

Some maintenance in spring is essential – clearing autumn leaves and branches
that wash down the valley into the system. This metal grid filters the leaves
and creates a collection point for them

Water can leak through the diversion channel

Mankind has harnessed water energy to power village life and labours for thousands of years, and there is no reason why this cannot still be the case for a great many places worldwide. A little further intelligent design of such systems could see other synergies incorporated. At the moment, for example, Necpaly villagers are toying with the idea of farming fish in the diversion channel, and another potential improvement could be to see overflows running into swales to subsequently and passively irrigate gardens, etc.

Tell us your micro-hydro tales!: I’d love to hear your micro-hydro stories. Not only for largish-turbine systems such as this, but also smaller power generating systems that might supply small house clusters, single houses, or even just aspects of a single house. Reading about these systems on the net is one thing, but getting practical insights and endorsement from people who’ve installed and/or tinkered with and tailored such systems speaks volumes more. Let us know either by comments below, or send a few pics and a short article to me on editor (at) permaculture.org.au for posting on this blog.

A Honey Buzzard patrols Necpaly – keeping the mouse population in check

A coconut shell is an excellent, biodegradable planter.
The coir (husk fibre) is extracted and mixed with soil to become a potting mix
with particularly good water retention capacity (the fibre reduces evaporation).

All photographs © Craig Mackintosh

The world’s largest water harvesting earthworks has transformed Sri Lanka, or at least large parts of it, from aridity to lushness. This mainframe design provides biological resources that villagers can use to maximise biodiversity for personal and environmental health. In similar fashion the ‘mainframe design’ of the ‘invisible structures’ of Sarvodaya’s community network provide avenues for the free flow of permaculture information to help achieve this goal. The good news is that many villagers are making use of these resources and this potential, despite constant attempts by Big Agri to lure them, through offers of free product samples and demonstrations, into chemical dependency.

Nandana Jayasinghe (inset), Director of Sarvodaya’s Agriculture Cluster and Development Education Institute in Thanamalwila, southern Sri Lanka, took me to see several sample home and market gardens. Nandana’s work is to help build on village level independence by supplementing, but not supplanting, local knowledge with permaculture techniques suitable for their climate and culture. Over recent years Nandana has been organising annual Permaculture Design Certificate (PDC) courses with visiting international trainers, as well as many other workshops.

Nandana tells me that about 80 villages within their network are specifically practicing permaculture, and counting, whilst remaining villages almost universally reject chemical based systems due to their disharmony with Sarvodaya’s agreed principles of prioritising the health of their environment.

After months without rain, mulch dries up and is easily blown away by regular
strong hot winds. Practitioners try to plant wind breaks to help here.

A buried clay pot, once filled and covered with a rag, slowly percolates water to plant roots whilst eliminating loss through evaporation

Gardening brings its own unique challenges for every locale in the world. While many of us are looking for biological solutions to creatures like slugs, aphids and caterpillars, your average permaculturist in Sri Lanka deals with ‘pests‘ of a whole other breed. Imagine walking outside to find dozens of peacocks feasting on your crops, for example. Keeping a determined monkey out of your yard is virtually impossible, and elephants…?

The ethical basis of permaculture intersects very well with the Buddhist majority of Sri Lanka, who have a deep respect for the right to life of all creatures within the biosphere. Where a rifle would quickly become the ’solution’ in other parts of the world – where the goalposts keep getting moved on what are regarded as ‘acceptable remaining population levels’ for various species, as we grow our economies – it is not even considered in most of this country, and would be greeted with scorn from neighbours. Instead, people here experiment with other imaginative alternatives. In regards to elephants, specifically, I had several villagers tell me the only people they’d heard of being killed by elephants were those who had previously resorted to violence against them – the family of a murdered or injured elephant would return to take revenge.

Sarvodaya villagers try to learn how to get along instead.

The Sri Lankan elephant, largest of the Asian elephant species (weighing up to
5400 kg), can wreak havoc in a home garden. Numerous methods are used to
discourage their presence, from hanging glass bottles together in trees
(which spook elephants by their sight and also sound as the wind disturbs
them), along with other reflective items.

A tree house serves as residence for a guard who is tasked with frightening
hungry elephants away at night by means of flashing lights and noise.
I saw trees larger than this that had been pushed over by elephants….

Monkeys are amongst the biggest challenges home gardeners face.
Despite appearances, this monkey is not being aggressive. It is simply yawning.

Much of Sri Lanka tends to be naturally arid. Where gardens are not in close proximity to a reservoir (called ‘tanks‘ in Sri Lanka) or their canals, or even where they are, water harvesting systems become an essential improvement. Many households featured rainwater harvesting tanks, provided by Sarvodaya. On my visit not a few were disconnected, however, simply because there had been no rain for months and unflushed empty pipes attracted lizards, snakes and other critters. When the rains come again, these are reconnected to supply drinking water and irrigation from rooftop rainfall.

A temporarily disconnected rainwater harvesting tank

Everywhere I went I asked the same question – particularly of older people: "Over the course of your life, have you noticed a change in weather patterns? And if so, what exactly?" Without exception, they all respond with "We get less rain." Nandana thus encourages and educates in the use of swales, composting, mulching and other water conservation practices. Permaculture can go a long way towards adapting to the impacts of climate change.

Unfortunately composting toilets are not considered here. The concept is culturally abhorrent to Sri Lankans in general and are thus disregarded outright. I suspect this may change over time as water shortages become more acute….

A palm frond covered trellis over vegetables protects from harsh
mid-summer sunlight and reduces evaporation.

One thing you find if you travel in 2/3rd world countries is that the people there usually look at you as if you’re somehow better off than they. It surprises them to realise you’re actually there to learn – that you’re there because they have something you don’t. In this case it’s a localised interdependence that secures them against the economic and social vulnerabilities we face in a globalised, peak oil world. I have immense respect, even envy, for communities that are able to provide for all or most of their own needs. An on-the-ground realisation of this appreciation often seemed to fill the people with a renewed sense of pride in what they’re able to achieve through their own labours and ingenuity. And so it should.

A biodiverse garden in the higher altitude district of south central Sri Lanka
provides more than 95% of this family’s food needs.

Because of the hoops you have to jump through to get organic certification,
Sarvodaya encourages home and market gardeners to develop Community
Supported Agriculture (CSA) schemes instead.

Biogas

Biodigesters are a permaculture design technique that are especially appreciated – with some home gardeners managing to make a closed loop for their energy requirements in this way. Families that have enough land to keep a few cows, and about US$100 or so for initial installation, can easily supply enough methane gas from a biogas system to fuel all their cooking requirements.

This biogas installation consists of three concrete lined chambers (see pic above). The one on the right is about two feet deep. Cow manure is shoveled into water here. The slurry flows through an underground pipe into the centre chamber, which is about 12 feet deep and three feet wide. Methane gas builds up in this chamber and flows through the small hose you can see running towards the house and into the kitchen (below). Overflow from this central chamber goes into the chamber at left, where it can be shoveled out and mixed into composts.

The nice blue flame indicates the clean burn you get from methane. The waste from three cows is more than sufficient to keep this fire burning for this family of eight, all day, every day – cooking grains and other food and boiling drinking water for improved health.

A few metres away, across the kitchen, is what they had to use before the biogas installation. As you can see, the gas cooker saves a lot of work in collecting oft-scarce firewood just to see it choke their lungs and the atmosphere. Dead wood can now be composted or used in construction instead and carbon emissions are reduced. Nandana estimates there are about 60 – 70 such biogas installations working efficiently within the Sarvodaya network to date.

Stay tuned for Part VII….

It’s taken a while to find the time to sit down and report on Part B of our earthworks here at Rosella Waters, near Cairns in far North Queensland. Phase I Part A was documented whilst the process was taking place. This latest update however will rely on memory and hurried notes made during the process, together with numerous photos. Large excavations such as the two large dams we constructed in part A are considerably easier to direct and far less time consuming than the finer detail work using smaller machinery as we experienced in putting in Part B.

Once again we had an excellent earthmover that came on the recommendation of the guys who did the two large dams. Sparky, as he is known, is a very knowledgeable and experienced earthmover, having spent a great deal of the last 40 odd years driving a 46 tonne excavator, building large scale dams, roads and “opening up new country”, as the saying round here goes. Now he runs a private earthmoving business and has at his disposal an 85HP bobcat and a 4 tonne mini excavator with numerous attachments. All of the following work was done with these two small machines.

The first part of the process in Part B was to construct a gabion rock wall at the very top of our system, in the gully that feeds our two dams. Previously, we had done a catchment analysis and based on the 1000mm of rain we receive per year, we arrived at a figure of 5,000,000 liters moving through it. We used this figure to calculate levels and engineer our spillways, level sill heights, the freeboard on the dam walls, trickle pipes, lock pipes, etc. The gully in question begins on our neighbour’s property. It is fed from the hill behind it and also from the diversion drains the road department puts in on the dirt road leading to our front gate. The catchment is predominately regrowth after being cleared 30 years ago with two dozers and a ball and chain. The catchment area is not a well functioning bio-diverse eco system and as such there is little water infiltration and a lot of sheet flow that brings top soil/sediment run off into our system. During the wet season of 2008 we did a small trial by hand building a rock wall just inside our fence line to get an idea of how much material would be trapped and how long it would take to fill up. After only 3 rain events, the small rock wall was fully backed up with silt 1.5 feet deep and the moisture remained just under the surface of that material well into our dry season. With that experience and the slight scar constructed at the back of the Lap Pool dam during its construction, we decided on a larger than first thought gabion, to (a) repair the damage caused by the construction of the Lap Pool dam (b) trap silt/top soil and sediment, preventing it washing through our system and ultimately ending up on the Great Barrier Reef, and (c) provide a small scale example of a solution to dry eroded gullies, that run like rivers in the wet, utilizing a “waste” product of local agriculture.

The “waste” product I speak of are the mountains of volcanic rock that many farms in the area have piled up in massive windrows. Farmers spend up to $4000 an acre to pull them out in preparation for planting avocados, potatoes, mangoes, bananas, sugar cane, etc. Rosella Waters sits right on the edge on an ancient lava flow so the farms that surround us are littered with such rocks, some as large as a car down to rocks as small as a grapefruit. We approached our neighbours up the top of the hill, who grow avocados and mangos, and who had recently put in a mass planting of new trees. Prior to that they had a 20 tonne excavator and dump truck working for a week to pull every rock out. They followed this by traversing over the land with a pickup and five workers pulling the grapefruit sized ones out by hand. Anyway, they were more than happy for us to go onto their property and select as many rocks as we liked from the windrows, which they had conveniently separated into different sizes.

Gabion rock wall trapping silt/sediment & top soil

The cost in building the gabion was therefore the time for Sparky to load up the individually selected rocks into his tip truck and then place them one by one with a claw on the end of his excavator arm. The process took two days in total and we estimate that it cost us close to $1800 to build. As we had large rocks to work with we decided against both “keying in” the base of the gabion wall into the side of the gully and constructing a net meshing to encase them in.

The volume and more importantly the velocity of the water coming down the gully in this case didn’t necessitate us doing either. Choosing the largest rocks first, we placed each one exactly where we wanted to create a firm base on which to construct the wall. It was built much in the same way as a dam wall is built, starting out wide at the base, six meters in this case, and tapering up to two meters wide at the top. The height of the gabion is nearly three meters. After placing each rock, Sparky would firm it down, swivel it around until it was firmly wedged. This in itself is more difficult than it might seem and does take time, but it is VERY important to get right. In all, the wall required 7 full dump truck loads of rock to construct. Once the main frame of the wall was complete we got another two loads of grapefruit sized rock which we have since placed by hand to smooth out the top of the gabion, thus providing a great access path across the gully that we can push a wheel barrow across, drive an ATV over or lead a goat and cart. To repair the scars at the side of the back of the Lap Pool Dam, just in front of the gabion wall, we placed some large rocks on the ledge and back filled behind the rocks with some top soil we had had set aside from the construction of the two dams. This was immediately cover cropped with cowpea and a crotalaria variety called gambia pea. All of the seed we used to cover crop was bought from a local seed merchant as seconds, which means there is a low strike rate (around 40%) but at $1 per kilo and having used the correct inoculant, we gained excellent coverage and stabilized the area. It’s important to remember that seed is the cheapest herbicide!

The next element we tackled was the overflow swale and spillway connected to the larger Mushroom Dam at the bottom of the property. We decided that after completing the gabion it would be best to start at the bottom of the system and then work our way back towards the front gate so that by the time it was all done, Sparky could load up and head off without risk of doing any damage with his machinery.

The first swale was only fifteen odd meters in length and had a level sill spillway half way along it that would spread the overflow of the system over a 3 meter wide area right on a broad ridge point, making it very safe to discharge and presenting no danger of causing an erosion gully. The construction of this small element proved to be a major turning point in our working relationship with Sparky. In the end it took the best part of a day to complete, due to a number of factors including our newfound language barrier. There were some important miscommunicated terms that needed clarification as we went: level sill spillway, back cut, swale, swale mound, swale dish, bottom of the swale dish and most importantly LEVEL. The idea that we wanted to construct something that didn’t run and was in fact perfectly level and on contour was quite a paradigm shift for Sparky, as in his words he had “spent his whole life draining landscapes” and what we wanted to do was quite the opposite.

The swale needed to be constructed on a steepish slope and we decided that we wanted it to hold 300mm of water in the base and have the top of the swale mound 800mm high – thus a substantial 500mm freeboard on the swale mound. The freeboard on the dam wall is one meter, so if ever there was a chance of water spilling over it would go over the swale mound first. It is unlikely to occur as we have “over engineered” things, but if it did the swale mound can be repaired with a shovel unlike the dam wall! What we soon discovered in constructing the swale was that due to the slope of the land we just wouldn’t have enough material to make the swale mound as high as we wished. The answer was to dig further up the hill from the back cut, as gently as possible, in a 1:1 cut. We didn’t want to dig too far up the hill so we adjusted the level of the swale mound back to 700mm high and with a three-meter long level sill spillway, the swale mound still wouldn’t be at risk.

First swale constructed leading off the Mushroom Dam

The data records for the region showed that the largest single 24-hour rain event in the last 30 years had been 284mm. We rounded this out to 300mm and built the spillway to be able to deal with ½ cubic meter of water per second. Together with another spillway on the swale connected to the opposite side of the dam wall, we have more than ensured the dam wall’s safety. Another safety margin we designed into the system was a 110mm lock pipe set at the bottom of the Mushroom Dam wall. The lock pipe is 27 meters long and goes right through the bottom of the wall. On the outlet side there is a butterfly valve, which can be opened wide in the event that the spillways aren’t coping. At the bottom of our system, and being our primary aquaculture dam, it also means we can drain this dam if needed. The dam also faces West, which is likely to be the direction of any fire entering our property, so in the event of a fire we have the added security of being able to drain 2.5 mega liters of water in that direction.

For ease of construction we built this first swale with the 85HP bobcat, equipped with a 1.7 meter wide tilt bucket. Time is money with earthworks, so we decided to make the swales a bucket width wide. Sparky started by running across the slope with his bucket following the back cut line we had marked out, corresponding to the high water mark of the dam. The spill was flicked down slope forming the first part of the swale mound. Once we had the basic shape and marked the position of the level sill spillway, Sparky used his tilt bucket to scrape beyond the back cut line up the slope to get the material we needed to gain the swale mound height we were after. We also took quite a bit of material from the area leading onto the dam wall, progressively cutting back to smooth out the sharpness of the cut. Sparky did a great job and we can easily drive through this area and up and onto the dam wall, giving us access to the other side of the property. The swale runs dead level at 300mm deep all the way through, from the exit point at the dam to the end of the swale itself. On the final scraping run we asked Sparky to tilt the blade slightly down slope in the swale dish, meaning that water will be predominated into the swale mound during rain events. With our first swale complete, fully seeded and earthmover trained we we’re ready to attack the rest of the design. Together with a mix of gambia pea, cow pea and pigeon pea we also planted sweet potato cuttings, aibika, cassava, pumpkin seeds, etc… giving us full cover leading into the wet. In the last few days we have started to receive our first rains in 9 months, so now we have a good base in which to begin our major plantings.

The next swale was a short one connected to the opposite side of the dam wall. It was constructed in the same fashion and care was taken again to ensure a smooth driveway leading off the dam wall for ease of access. With not much room to play with within our boundary line, the swale was extended right up to the fence line with our neighbours and the three-meter level sill spillway will serve as discharge of excess water into the creek below, and also as access to behind the dam wall and our Zone IV area of the property.

Moving further up the slope, we then tackled the 25-meter long swale connected to the Lap Pool dam. With this swale we had a few important decisions to make. Firstly it was going to be the Lap Pool’s only swale and only level sill spillway, the overflow from this leading to the Mushroom dam. The placement of this level sill was therefore vitally important as it would be the major source of water that fills the Mushroom dam and we also have future plans for structures connected to the 6m x 3m jetty we placed on the dam. We saw the opportunity for the level sill to be a feature and a potential wet/dry growing area, in close proximity to the jetty and eventual cabin connected to it. We decided to step the overflow down into a further two level sills before it entered the Mushroom dam.

The step down spillways leading overflow from the Lap Pool Dam swale into the Mushroom Dam. Jetty posts in waiting.

In this way, we slow down the volume of water, create further edge and add an aesthetic feature in the process. The level ditches are slightly wider than the level sill on the swale itself and together with generous amounts of cover crop seed, we planted clumps of vetiver grass to further stabilize the area and slow down water flow. We used the same technique on all the level sill spillways. With such an abundance of rock at hand and a couple of quite steep spillways to stabilize, we saw this as our best option. On two steep spillways, we planted out clumps of vetiver grass across the slope, starting at the top and offset all the way down. Then we placed rocks from the bottom up, starting with larger rocks in an arc, wider than the spillway, followed by smaller rocks all the way up the spillway wall face. We left a 200mm space around each of the vetiver clumps and now 3 months later we have a very stable, rock wall face to our spillways, with large clumps of green vetiver grass breaking up the brown.

Back on the Lap Pool swale we asked Sparky to dig ½ meter deep x 1 meter long x ½ meter wide ditches within the swale dish itself. These ditches will hold water for longer than the rest of the 300mm deep swale and as such become growing zones for some wet crops. We now have these ditches planted out with Taro, with water chestnuts on the edges, all of which is shaded by bananas growing at the inside edge of the swale mound.

Lap Pool swale with newly planted Taro and water chestnuts in the pits and banana on the edges.

Again the whole swale was cover cropped with cowpea, Gambia pea, pigeon pea and dotted with cassava, Aibika, sweet potato and pumpkins. The larger long-term support species and variety of fruit and nut trees are now ready to be planted. We had considered putting all of plantings in at the same time but with no rain at all for close to 9 months we decided to get cover crops and shorter term nitrogen fixers going and wait for the beginning of the first rains before putting them in. The earthworks couldn’t be put back to a more appropriate time due to the availability of machinery.

The rice paddy system was by far the biggest challenge. To look at now, it seems all we have done is push a little dirt up to make a wall and dig a couple of holes for the ducks to live near. In a sense that’s true, but the process of constructing the 1:300 diversion drain from the Lap Pool dam to a duck pond connected to a rice paddy (the overflow of which runs along a diversion drain with a 20mm fall over 20 meters, to another duck pond connected to another rice paddy, the discharge of which drops down into a 25 meter long bio-filter which is itself a level sill spillway), dropping water into the Mushroom dam wasn’t that simple! Plus, the overflow of the second duck pond, leads to a short swale with level spillway that drops down to a 20-meter long swale, the spillway of which also drops into the bio-filter before being discharged into the Mushroom dam. Phew.

The rice paddies with bio-filter below. The beach area is on the edge of the Mushroom Dam with the back side of the Lap Pool Dam wall behind it.

A great deal of gravel road base material was taken out of the rice paddy area and we used this to repair/construct a proper ringed access road, our main access road on the property. The road has now been graded correctly so that water will run into drains leading along side it directed to water storages. On the road we have placed 150mm x 50mm x 4 meter long blue gum planks in sets of two, 4 inches apart, at an angle across the road, every 10-12 meters. We first heard of this idea from Rainbow Valley Farm in New Zealand who has the same system on much steeper roads. As water runs over the road it only has a short distance to run before it drops down into these drains that run across the road at a slight angle. By not allowing the water to build up speed over the road surface the material stays on the road rather than down the bottom of the hill, with obvious benefits.

The diversion drain leading to the 1st duck pond needed to fall at 1:300 and be set low enough in the Lap Pool dam so that it was the first water to leave the dam as it filled. We can regulate this fact by capping the end of the 150mm pipe. The level at which we set the150mm diversion pipe was 450mm below the high water mark of the dam which also corresponds to the level of the level sill spillway. That is 150mm lower than the depth of the swale and the level at which water exits the dam into the swale. As I said, setting the pipe at that level ensures we can control when the water heads to the duck ponds. We have a 30,000 L concrete water tank connected to our shed with approximately 100,000 L of potential roof catchment. We needed to decide what to do with the extra 70,000L. In a minor brain wave, we came up with the idea to pipe the overflow through a 90mm pipe down the side of the tank, under the road and into the 150mm diversion pipe with a t-piece. At the entry point into to first duck pond, we have rocked the spill and next to the 150mm diversion drain pipe we have another 150mm pipe under the road that collects all the water in the drain running alongside the road. At the end of the drain along the side of the road we have dug a meter deep silt trap, concreted the base and placed a grill over the top. This will keep silt out of the duck ponds and provide another source of potting mix from the material that does ultimately come from the road.

The main issue we faced with the levels we were dealing with was to get the duck ponds as high up the slope as we could, leaving us room to put in the proposed rice paddies. The duck ponds would end up being quite small as a result and have a 800mm slope at the back of them from the ridge road. We saw this back slope as another opportunity to be creative and decided to step this down in 300mm wide ledges to the high water level of the ponds. The end result is a duck pond amphitheatre on both ponds! This stepped area will be fully planted out with duck habitat and forage, shading the ponds in the process.

Duck ponds at the back of the paddies, connected by a diversion drain. The amphitheatres at the back of the ponds are well cover cropped and stable.

The two ponds are connected by a diversion drain that runs from 1st pond to 2nd pond, with a 20mm fall over its 20-meter length. This isn’t a great deal of fall, but it’s enough. It has meant we have been able to keep the 2nd pond up as high a possible to give us room for the paddy below. The water from the duck ponds are released into the paddies by way of gates we picked up from an old rice farmer up here. They used to grow two crops a season using the channel that leads from Tinaroo Dam as a source of their water. One of the reasons they gave it up was when the cost of water went from $8 p/ML to $18 p/ML. Now they flood irrigate sugar cane instead. We swapped the four gates for a case of beer and made metal plates that slide into the 3mm gap in the concrete gates, to control the flow of water. The same gates are used at the exit end of the paddies, to discharge the nutrient rich water into the bio-filter below before it heads to the Mushroom dam.

The bio-filter that acts a level sill, taking nutrient rich water from the paddies as well as the swale in the background at the base of the chicken tractor system, overflows into the Mushroom Dam.

The two paddies are separated by a meter wide bund and surrounded by a meter wide, meter high bund with a slight grade. All of this will become a growing zone for duck forage, mulch and some soft fruits such as pawpaw and banana. The meter high bunds, once planted out, will become a living fence keeping the ducks in the paddies during the rice-growing season. We plan to grow rice using the integrated rice and duck growing system I had learnt whilst living with Takao Furuno and his family in Japan. Takao is a social entrepreneur with the world economic forum with his rice duck growing system and has an excellent book out through Tagari publications titled “The Power of Duck”.

The short swale connected to the second duck pond drops down into a longer swale, which will form part of our chicken tractor system. This 20 meter long swale lies at the bottom of the contour chicken runs and borders the Mushroom dam. It’ll take excess nutrients from the chicken system and grow some large trees on the north side of the dam, providing shade. Due to this swale being constructed on less of a slope than the first, it was built with the four tonne excavator. Working from the downward side of the swale, the bucket cut on the back cut line and the spill was dropped to create the swale mound. Following Sparky along with the laser we ensured that the swale dish was 200mm level all along. It doesn’t need to be within a mm but it does help to make the dish as level as possible so as to get an even distribution of water along the swale in lesser rain fall events. Obviously the best way to check that level is to fill the completed swale with water and adjust accordingly with a shovel. It is cheaper to do this in your own time than to pay $100 an hour for a 4 tonne excavator to do it.

“Hairy Harry” stands tall on the island at the back of the Keyhole Dam.

The final element to put in was the Keyhole dam at the entrance to our property. We named this pond the Keyhole, as it is the key to the system that connects water on both sides of the property. The Keyhole sits on a central ridge that dissects the property and the idea was to create a small water storage in our Zone 2 area that can move water through either the system described above or to future water storages on the river side of the property, or both. We decided how large a storage of water we wanted and marked out the approximate position of the dam wall for Sparky to follow. We set a target level for our high water and corresponded this to the position of the two swales that were to direct water to the Keyhole via 150mm pipes placed under the access road. The wall was built using the bobcat, layering wetted clay followed by numerous track rolls with the same machine. Using the excavator to dig the hole of the dam, material was mixed using the tilt bucket with me standing close by, hose in hand, making sure there was the right amount of moisture to make the clay bond. Dam and pond walls are all about compaction and with enough of the right clay, a little mixing if the material is good and bad, and the correct amount of moisture, things should seal. We decided to create a small island at the back of the Keyhole as an aesthetic feature, duck habitat and for the fact that the palm we’ve named “Hairy Harry” was too good looking to lose.

Once the Keyhole was built with a 400mm freeboard on it, we set about marking the back cuts of the two swales that were to connect to it. The Mediterranean swale (so named due to quite granite soils in that part of the property) leads out towards the header tank and drops its spill down into the Lap Pool dam. It is connected to the Keyhole via a 150mm pipe, under the road with a slight 20mm drop towards the pond so as to not get stagnant water sitting in the pipe.

The Mediterranean swale connects to the Keyhole Dam via a 150mm pipe under the main access road. The level sill spills water into the Lap Pool Dam below.

The end of the pipe can be capped, if we wish to keep water in the Keyhole dam and direct any overflow via the 150mm pipe under the road on the other side that connects the Council swale to the same dam. We called that one the Council swale because its main catchment comes from a slight improvement to the dirt road the council recently graded. It was graded sloping towards our fence with no drain so in large rain events we would get large sheet flows of water moving through the landscape causing unnecessary erosion. We asked Sparky if he wouldn’t mind creating a little spoon drain 100 meters up to the neighbours gate entrance and directing that water through the culvert under our road entrance. The five meters beyond the culvert to our fence line continued as a drain before entering our property where it then becomes a level swale directing a substantial volume of water through the 150mm pipe, under the road, into the Keyhole dam and ultimately through our entire system.

Considering the volume of material we are likely to receive from the dirt road, we placed a 200mm deep x three-meter wide silt trap just inside the fence line. This can be dug out by hand when necessary. The level sill spillway of this Council swale directs overflow to a gully, which in future may become a dam or a large gabion, subject to future test holes to check for clay content.
Either pipe in either swale can be capped to control the direction of water movement through our system. This small dam feature is something we are really happy with for its aesthetic beauty and complex simplicity in functionality.

This spoon drain runs 100 meters long and will direct a large amount of water through our system via the Council swale that connects the Keyhole Dam.

For our first major earthworks the complexity involved in the design was substantial. It was quite a big undertaking, made even more so by the birth of our second son Dylan smack bang in the middle of it all. At this point I must give special recognition to my darling wife Georgie who at 41 weeks pregnant, kept us fed and watered, took all the photos and spent considerable time standing there with FRED ( Forever Ridiculous Electronic Device) i.e. the lazer level staff and receiver, in 33′C tropical heat. We took close to a year observing the site, designing, listening and talking to others, re-designing and planning the earthworks and the immediate repair work after they’re done. Once the earthworks began, concept became reality and the two can be quite different no matter how good the planning. Each evening after Sparky had left we spent time talking things over and making decisions for the next day’s work. We gave our laser level a really good working over, it has been a great investment; I don’t imagine we could have done all that we did without it.

Now that the mainframe infrastructure is in place, a little water is in the dams and the site is green with cover crops, the system has literally come alive. From seemingly nowhere frogs have descended upon the water storages attracting ever-increasing numbers of birds. The place must look like a red-light sale at a discount store – a hydrated green oasis in an otherwise dry landscape.

Overlooking the system from the header tank. A transformed landscape.

A natural spring we knew existed has started to recharge with the water in the swales from irrigating the cover crops. It moves through the sub-soil leaking out into the side of the dam. Our hope is that this recharged system will help to keep the water level more constant in the Mushroom dam by offsetting any evaporation.

In all, the earthworks took close to two months to complete from start to finish with a total of 16 days of actual earthworks involved. With the start of our seasonal wet season rains upon us, the next three months or more will be spent busily planting, planting and more planting. We know Sparky is coming back when the wet really hits – we made a pact to sit down with a beer together in the pouring rain and watch the system operate in full flight. Through a local NRM group we are also planning an open day, for local farmers to come and see the system. These major earthworks are just the start of a great adventure in the development of our Permaculture demonstration site for the wet/dry tropics of Northern Australia, Rosella Waters.

India is a country where water shortages have become so acute that the failed monsoon rains in 2009 had people literally killing each other over buckets of water, and tensions are still rising. (See this video also.) In many places cities are receiving less than half the water their populations need to meet basic requirements, and the constant bickering between individual states often breaks down into violent clashes.

Glaciers that provide melt water in the north are disappearing. and fast. Indians are simultaneously switching to a more westernised diet, which has enormous impacts on water usage, and large scale monocrops for biofuels add to the disaster. Presently 90% of India’s water usage is for agriculture. This percentage is rising, whilst competition is increasing with the growing industrial sector. India’s population is expected to surge to 1.5 billion people by 2050, and the country is still rapidly urbanising – with city dwellers using a lot more water than their rural counterparts. It is predicted that by 2020 most major Indian cities will run dry.

And India is not alone with these problems.

Businesses, of course, are making the most of the situation to cash in on the intense demand. I think it’s time to pay attention to water harvesting words of wisdom, and solve these problems at source – and in doing so also heal the land:

With wisdom and wit, Anupam Mishra talks about the amazing feats of engineering built centuries ago by the people of India’s Golden Desert to harvest water. These structures are still used today — and are often superior to modern water megaprojects. – YouTube

Hat Tip: Robert Windt

And, for good measure:

Further Reading:

• Letters from Sri Lanka – The World’s Largest Water Harvesting Earthworks Project
• The Muffin Tin and the Sponge
• Harvesting Urban Drool
• Water Harvesting DVD
• Water Worries

The ABC just ran an interesting spotlight (video – or transcript here if you prefer) where we learn that one of Yeomans’ properties, ‘Yobarnie’, in Richmond, north of Sydney, is facing ‘development’ that would turn this important historical demonstration site into a housing estate. In the 1950s and ’60s the site attracted busloads of people on weekend tours where observers could see the transformation his methods effected and learn about their implementation.

Yeomans’ methods, which have heavily influenced permaculture design systems, are increasingly seen today as having tremendous potential to not only increase agricultural productivity but also to have a significant impact on reducing atmospheric CO2 concentrations through increasing soil carbon levels.

It’s a sad day when such a site, with not only such historical significance, but also present relevance, would be paved over.

For good measure, here’s a YouTube clip of Darren Doherty showing the before and after effect of a single keyline plowing on his property.

Resources:

• Keyline Plowing with Compost Tea Application
• The Keyline Plan by P. A. Yeomans
• The Challenge of Landscape by P. A. Yeomans
• The City Forest by P. A. Yeomans

Download: You’ll see the option to download the 913 megabyte MP4 file at bottom right side of this page.

YouTube: The video can also be watched on YouTube, in four segments, here, here, here and here.

Greening the Desert II (including Part I) – Greening the Middle East
(Duration: 36 mins)
Tips for playing: If it’s slow to load, turn off High Definition (HD) on the player.
If you still have problems, click play (on low or high def) and then after it’s started,
click on pause. The video will then continue to buffer into your computer.
Play once fully loaded.

I would like to take the opportunity to thank Kelly Kellogg at this juncture. Kelly donated initial funding that enabled the purchase of the land for the Jordan Valley Permaculture Project site (aka ‘Greening the Desert – the Sequel’). But, upon watching the Greening the Desert Part II video, Kelly was inspired to donate an additional $20,000. These gifts are very encouraging to us as we try to solve problems at source (teach a man to fish…). Others who may feel inspired to donate to help us move this work forward faster can do so here.

A little background on the video follows:

Children in a school playground, Al Jawfa, Jordan Valley

When there’s no soil, no water, no shade, and where the sun beats down on you to the tune of over 50°C (122°F), the word ‘poverty’ begins to take on a whole new meaning. It is distinct and surreal. It’s a land of dust, flies, intense heat and almost complete dependency on supply lines outside of ones control. This is the remains of what was once called the ‘fertile crescent’. It is the result of thousands of years of abuse. It is a glimpse at a world where the environment – whose services provide for all human need – has all but completely abandoned us. This is a glimpse at the world our consumer society is inexorably moving towards, as our exponential-growth culture gorges itself at ever-increasing rates.

The original Greening the Desert video clip has been watched hundreds of thousands of times and has been posted to countless blogs and web pages in the datasphere. Although only five minutes long, it has inspired people around the globe, daring the lucid ones amongst us, those who can see the writing on the wall, to begin to hope and believe in an abundant future – a future where our survival doesn’t have to be based on undermining and depleting the very resources of soil, water, phosphorus, etc. that we depend on. The work profiled in that clip demonstrates that humanity can be a positive element within the biosphere. Man doesn’t have to destroy. Man can repair.

In the clip at top I introduce you today to Greening the Desert II. I shot the footage for this video last month (October 2009) and edited it on location in the Dead Sea Valley in Jordan – the lowest place on earth, at 400 metres below sea level. Much of it was shot in or near the village of Al Jawfa where I stayed, which is effectively a Palestinian refugee camp that has morphed over the decades since 1948 into something resembling a functional small town. It was first shown to delegates of the ninth International Permaculture Conference (IPC9) in Malawi, Africa at the very beginning of November and is now being released for general consumption. The video will take you to the original Greening the Desert site, letting you see its present condition after six years of neglect when funding ran out in 2003. You’ll also be introduced to our new project site – the Jordan Valley Permaculture Project, aka ‘Greening the Desert, the Sequel’ – and see some of the spin-off effects within Jordan from the influence of the original site; promises of much more to come.

The work we’re undertaking in Jordan is in accordance with what we call the ‘Permaculture Master Plan‘, where the project’s future is assured through funding from running educational courses. Project sites thus become self-sufficient, and self-replicating.

Geoff Lawton instructs students in a school yard in Jordan, one that PRI has
just created and begun the implementation of a design for, so its
many children can see, experience and learn permaculture first hand

Through this work we envision thousands of educational demonstration sites worldwide – all inspiring and teaching communities around them how to begin to tackle at root the massive challenges we now face after decades of short-term profit-based thinking has all but ‘consumed’ our planet and dismantled the social constructs that the human race has always depended on for its survival. Through this work we see desertification stopped in its tracks, and reversed. We see this century’s dire water issues getting resolved. We see productive work for millions in bypassing the irrelevant efforts of our ‘leaders’, to instead build a new kind of culture – a culture based on cooperative effort and learning. It’s a culture where its members have regained a sense of their place in creation, where they become land-based stewards of remaining resources; creating a culture where we at last find ultimate satisfaction – promoting and building peace and low-carbon, relocalised, community-based prosperity.

We have many such ‘Master Plan’ projects in various stages of development worldwide, and a steady stream of enquiries from people around the globe wanting to get involved and help widen this cooperative network. Perhaps it’s time you took a look at Permaculture? After all, do you have something more worthwhile to do?

Jordan Valley

Geoff Lawton and Darren Doherty are the two highest profile people in Australian Permaculture when it comes to broadacre water harvesting earthworks. They’ve both had success in some very tough environments, and yet it’s interesting that their styles are quite different, particularly when it comes to infiltration strategies.

This article is a short comparison of their approaches, along with an idea I had recently for amalgamating the benefits of each.

To help illustrate, I’ve put a set of boundaries on a section of a topographic map (figure 1.1). 

Figure 1.1 – Base Map

I realise that both Geoff and Darren would be salivating as they looked up the hill at the potential dam sites above, but I’ve deliberately left them out of the equation to keep things simple and limit the comparison to their infiltration strategies.

Similarly, although I haven’t marked it in, each of them would put in a small dam/wetland/silt-trap in each of the valleys to dissipate the flow coming on site and prevent their mounds blowing out.

Geoff Lawton’s approach

Geoff’s style for infiltrating water into the landscape is to use swales (often connected to dams but that’s another story). His aim is to catch water as high as he can in the landscape and use the dead level swale to spread the water across the length of the land. This water is held in the swale, giving it time to infiltrate into the soil, and it then plumes downhill, recharging the ground water for the benefit of trees planted below (figure 2.1).

Figure 2.1 – Soil water movement after swale infiltration
See this animation for more details

He often builds his swales with a bulldozer, resulting in a large capacity (eg a bulldozer blade wide and deep as in figure 2.2 – the back and front walls are battered on the subsequent passes).

 
Figure 2.2 - Front view of a bulldozer building a swale 

This is well suited to the sub-tropics where 50-100mm events are common and also in arid areas where the few rain events that occur can be a deluge. A large volume of water is held in the swale, giving it time to infiltrate into the landscape, for the benefit of the trees planted below.

A design constant we can work with is that water flows at 90 degrees to contour, both above and below the soil surface. Each large red dot in figure 2.3 represents an even amount of water that has infiltrated along the length of the swale. The red lines show the path that the water takes as it moves down through the soil profile.

Figure 2.3 Swale infiltration (red) path

Natural water flow in the landscape

A natural pattern in the landscape is that valleys are moist whereas ridges are dry. You can see this in the vegetation in any undulating National Park you go walking in, with lush, moisture loving plants in the valleys, and dry sclerophyll forest on the ridges.

In figure 3.1, each large blue dot represents an even amount of rainwater that has infiltrated into the land above our boundary. The dotted lines show the path that the water takes (90 degrees to contour) as it moves down through the soil profile. This image clearly illustrating why it is that the ridges are much drier than the valleys.

Figure 3.1 – Movement of soil moisture

Darren’s argument against swales in some instances

In figure 4.1 below, I’ve overlayed the swale infiltration path (figure 2.2) over the top of the rainfall infiltration (figure 3.1). As you’ll notice, the swale tends to direct far more water towards the valleys and hasn’t really fixed the issue of our dry ridgelines.

Figure 4.1 Swale infiltration (red) in relation to moisture entering site (light blue)

Recognising this issue, Darren prefers to set out tree lines using a keyline pattern. In this aerial shot of George Howson’s agroforestry property, ‘Dalpura’ (figure 4.2), the tree mounds aren’t on contour but rather they gently slope away from the valleys (the naturally moist areas) towards the ridges (the naturally dry areas), therefore aiming to even out the moisture levels across the landscape.

Figure 4.2 Dalpura tree lines from above

He creates his tree lines using a ripper and mounder, common in forestry plantings, which have a small gutter on the upper and lower sides which help to direct the water.  This is a cheaper and more fuel efficient option than a bulldozer or excavator, and works well in climates where rainfall events are generally consistent but small, such as in many temperate landscapes.

The green dots and arrows in figure 4.3 indicate the infiltration of the keyline mound during a small event. Water has been directed away from the valleys and encouraged to infiltrate on the ridge instead. You’ll notice that when combined with the water naturally moving down through the landscape from above, the moisture distribution is far more even than in the swale in figure 4.1

Figure 4.3 – Keyline mound infiltration (green) in a small rain event

Despite the obvious benefits, one downside I see to this approach is that the gutters on the sides of the tree mounds have a relatively small water holding capacity. If the landscape has dried out significantly, for instance during a long drought, it’s highly possible that the soils will become hydrophobic, and therefore there will be little water infiltrating as it travels along the gutters. During a large rain event, which occasionally come during the summer when moisture is most needed, due to the small capacity of the gutters, only a small amount of water will be held and given time to infiltrate. The rest will spill over the mound and down the ridge (figure 4.4). This would particularly be the case where there is a large catchment above as in the example used.

Figure 4.4 – Keyline mound overflow during a large rain event

(Note: At this point, I should mention that despite Darren’s mounds being smaller than Geoff’s swales, he places one for every line of trees, meaning that water infiltrates right at the base of each tree. Also, in the widescale forestry example of figure 4.2, the pasture in between the rows has been ripped using a keyline plow, which further increases the infiltration capacity. Similarly, when water does spill, it is in the best place possible – right up on the ridge where the water will fan out and have further opportunity to infiltrate)

The comparison in brief

Geoff’s swales – hold plenty of water in a large event but distribute the water less evenly in the landscape below

Darren’s keyline mounds – distributes soil water more evenly across the land, but holds and infiltrates less during a large event.

The keyline swale

With the benefits of each in mind, I came up with a hybrid, which you could call a keyline-swale.

It’s built just like a swale, set out on contour, except that the base of the swale isn’t level, rather it slopes from the valley out towards the ridges.

To build the keyline-swale, pegs are set out on contour. Starting at the ridge, a mark is made on each peg, rising at 1 in 500 towards the valleys. This is the guide for the blade depth (figure 5.1).

Figure 5.1 – Side section view of a bulldozer building a keyline swale

During a small rainfall event (figures 5.2 & 5.3), water is directed along the trench from the valleys to the ridges, where it infiltrates in a very similar pattern to Darren’s keyline mound.

Figure 5.2 Side section of a keyline swale during a small rain event

Figure 5.3 – Keyline swale (dark blue) infiltrating during a small rain event

During a large event, the water would fill up along the length like Geoff’s large swale, however the water depth wouldn’t be constant. One possible benefit of having a greater depth of water out on the ridges is that there will be more pressure here, causing water to infiltrate at a faster rate than it will in the valleys (figures 5.4 5.5). As the water level drops, it will of course infiltrate the remaining water on the ridge.

Figure 5.4 – Keyline swale full

Figure 5.5 – Keyline swale (dark blue) infiltrating during a large rain event

If this was a temperate climate where large rainfall events are rare, on this landscape I would go for a keyline swale at the very top of the property, and then use Darren’s keyline mounds parallel to this down the slope. This means you’ll get the benefits of water being infiltrated at the base of each of the tree rows (by the mounds), hydration of the ridgelines, while also capturing any large flows that enter the property, infiltrating them right at the top of the slope.

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Cam Wilson runs Forest Edge Permaculture Design, a Melbourne based consultancy offering permaculture Design, Education and Implementation. See the website for more details.