Water mitigation

The last few days, its been wet, wet, WET! While grateful for the rain, it will be nice for it to start clearing by tomorrow, as the forecasters predict. Mostly because I had such a wonderful time in the garden previously, moving dirt, planting seeds and basically getting stuff done, I would love to be out there again.

Now is a good time though to see how all that water is moving around the property. There's no better place to start than the new swale I was digging recently, near the bush orchard. But first, lets take a trip back to 2013, when I proposed my initial plan for swales in this area...

The plan

Back in 2013, I wrote about the progress on the lower of the two swales, just within view of the picture above. It was a nice start, but recently I decided to expand the lower swale and start the upper one. I wasn't going to write about it until I had at lease ONE of the two, finished.

However, the recent rain has shown me how effective, even these half finished swales are. Here is the upper swale...

Newly dug, upper swale

It's completely full now and in stark contrast to the lower swale. Please excuse the grey-water hose below...

Expanded, lower swale

The reason the upper swale is full in comparison, is because the water coming off the concrete slab we initially laid for the driveway, is filling it. The location of the upper swale is positioned such as to catch this trickle of water, high on the slope.

 Concrete driveway, right.

Depending how heavy the rain is, the water gradually sheds onto the grass and trickles down into the newly dug swale.

Catching water

The water is entering just above the swale, where there is no grass. That's where I was digging recently, and actually wanted to know if the water would indeed follow this path. It seems the theory is sound in practice.

Upper and lower swales

The beauty is, these two swales will be joined at some point, so when the upper swale fills to capacity, it will flow into the lower swale. It's amazing to see that small trickle of water from the driveway, can actually be caught and stored in such a way.

The design of the driveway, may have started with a concrete slab, but I'm glad we decided to finish the driveway to the bottom, with concrete grid pavers instead.

Stopping the water down slope

You can see the cells are filling with water, but not making the water run. Some of the cells overflow into the lower ones, but we certainly don't get the kind of water shed we get from the concrete slab above the grids.


It has meant the water which collects at the bottom of the driveway, is lessened to such a degree, we don't have big mud puddles. Those particular delicacies are reserved for other parts of the property now, just not at the bottom of the driveway so much!

It's good to see some of our ideas in water management, actually work in practice.


PS: Do any of the locals know where I can find a Davidson Plum tree, to collect seed from? I would like to replace the ones which died in the Bush Orchard.

Update

Just a quick update on my bush orchard swales, dug recently. We received some rain so I was eager to check how the swales performed. The top swale above the native peanut tree, had the benefit of an overhanging tree branch, to collectively drip its water into the swale.

Upper swale

The lower swale underneath the same tree, collected water too. From both images I can tell it is definitely lower on one side, so the contour is not level. It is what I suspected as I was digging, but it was good to have it verified.

Lower swale

I would have dug deeper on the far side, except I had a few tree trunks that we chopped down getting in the way. I would have to chop away at them with an axe, which is not something I wanted to do. But I think these swales hold enough water, worth the exercise of digging them.

All that is left to do now is to mulch over the top and wait for the settling period. It will eventually even out on contour, when silt and debris fall into the lower spots.

There are more swales to be dug, but I'm happy with what I've done for now.

Handmade swales

This time of year is traditionally the driest for our area. Winter is gone and Spring is warming the days nicely. Before our crucial summer storm season arrives however, we can have up to a month of hot, dry and windy conditions. It's terrible on the soil and we don't have extra water to go around. So the answer has to be swales...

Native peanut tree planted 2 years ago

I started to dig a long, shallow trench by hand yesterday, with a mattock and rake. While it's incredibly slow and hard work, there is little chance for mistakes to be made. I gently chisel away at the earth until a shelf is formed to catch the rainwater when it does arrive. It's the basic cut and fill principal, but the shape of the swale has to run exactly on contour, or it will drain water down hill again, rather than capture and hold it - which is what we're aiming for.

This is just the first swale I've dug for this area...I plan at least two more.

North facing slope receives full sun - picture taken in AM

Above, is what the slope looks like without swales. It gives perfect drainage, which means a lot of "constant" water is required to keep this area moist - not present at the moment. The poor plants I've been attempting to grow, always struggle during this period. With the implementation of regular swales down the slope however, it will prolong the natural irrigation it does receive with each rain event.

The swale plan is this..

Earthworks are carbon friendly, as they're dug by hand

It may take a while to dig by hand, but the best part is free labour with no associated fuel costs. Unless food counts - but I was planning on eating anyway. I've noticed the cut and fill on contour, makes for navigating the slopes a lot easier too. This will be very handy the older we get! David has already killed two domestic mowers in six years, cutting the grass on these unforgiving inclines. Hopefully we'll be able to put in more trees (this is our bush-tucker area) so the canopy shade will gradually out-compete the grass.

One of the complimentary ideas with swales is planting trees below them, so they'll be fed nutrients and watered from the swale above. It's kind of like an irrigation pipe made out of sculpted earth. No plastic hoses or extra water tanks required. That makes my bank account, much happier!

It just goes to show that even when you do have slopes, they can be tamed. Not only is it good for the owners, but it's also sensible land management - giving nature a helping hand along the way. All you need is some hand tools, a basic plan and a little (okay, a lot!) of sweat.

Our bush orchard

We are starting to plant out a bush orchard on our property line. We tried to do this about two years ago, but the neighbour's goats decimated anything we tried to grow there. One lone Grevillea (copper rocket) and an Ivory Curl tree survived the relentless stripping, until we decided to start some serious caging.

The trio of goats died unexpectedly after the Queensland floods, which wasn't an uncommon thing amongst property owners in this region - we lost 3 healthy chickens too. With the eating habits of the goats a thing of the past though (not being heartless, just practical) we're trying to get plants established in time for the Spring flush of growth.

So what's exactly contained in our bush orchard, and what do we hope to achieve with it?

Mandarin in fruit; delicious and nutritious
~ but not native ~

Well it's certainly not like an orchard of European varieties of fruit trees and shrubs, which most backyard gardeners are familiar with (apples, oranges and berries). Rather, it will have only native varieties which produce a crop of native fruits. Some of them can be used by us, in jams, dried or eaten fresh, but for the most part we wanted this bush orchard for the native animals.

Before I get into the whys about the orchard, I wanted to show the layout and some of the plant varieties we've selected. They're only very small at this stage, but still worth recording for future reference. The first plant, is a Davidsons Plum. Feel free to press on the link for more information.

Davidsons Plum
sourced from Daleys Fruit trees

The fruits of these plums are not as sweet as their European counterparts, but are reported to make a most excellent jam. Something I'm very much looking forward to trying in the kitchen. Another plant we selected for the purpose of stabilising the soil however, is a sandpaper fig.

Sandpaper Fig
sourced from Daleys Fruit trees

We hope to propagate it at a later date, for planting along the banks where we get some powerful water flows in storm season. Why is it called a sandpaper fig you may ask? It's leafs actually feel abrasive like sandpaper, and indigenous Australians used it to refine their wooden hunting tools. You betcha, I'm going to get a piece of wood and try this out for myself, only when the leafs are a little bigger!

Next is a peanut tree which is a rainforest tree, but shouldn't grow too big in this belt of trees.

Peanut Tree
sourced from Daleys Fruit trees

The nuts inside the fruit are said to taste "nutty", but we wanted it specifically because it's a native food source for birds and a lot of nocturnal animals we don't get the opportunity to see much of, like bushrats and bandicoots.

I also have a Burdekin Plum which I haven't planted yet, but it's also a favourite of fruit bats apparently. Before anyone asks if I'm crazy for wanting to attract fruit bats (Flying Foxes, otherwise known for their ravenous appetite for all things fruit) to our garden, the European trees (like paw paw and bananas) are going to do that anyway. Our native bats which are really quite adorable, actually prefer native fruits over European varieties. We wanted to cater to their natural diet. We'll still have to take measures to protect our other fruit trees, but we're hoping the "lure" to better food is going to keep them happily occupied.

Lemon Myrtle
sourced from local markets

The Lemon Myrtle or backhousia citriodora, is another bee and bird food source, but it's also a great herb to use in cooking. We're hoping to be able to substitute the leaves from this tree, instead of using bay leafs. After all, the bay tree can get quite big in the ground. A more native solution is going to meet the need with less impact to the environment.

In fact, any impact that will be felt in our bush orchard will be one of mass fertility as every possum, bandicoot, wallaby, bird, bat, echindna (yes, we get those too) and many other native animals, feast and drop their dung! This is what we want. We want native animals, filled with native food, dropping their gorgeous native dung absolutely everywhere. They will be our little beasts of burden, carrying their fertility around the property and hopefully spreading it around the region too.

But what about the layout? How does it all fit together? First, our property boundary which is noted by the neighbours white fence below: this faces approximately west. The trees are in a northerly facing line.

A row of new natives in amongst the old

Even in winter, the sun is low enough to penetrate the canopy for secondary plants - or lower growing shrubs such as grevilleas, westringas and rosellas. All plants we hope to add more of once the trees get a bit more growth on them.

At this stage it's just a straight slope too, but we're already dropping leaf material, branches, dead grass and soil on the contour to create swales. These are not intended to be engineered for precision, or to catch and store large amounts of water. They're more to alter the energy of water running straight down the hill and to capture at least a small amount of moisture to last through times without rain.

The beginnings of a swale, which is just dead grass at this stage

The area above was the first section we actually developed when we first moved here, before the goats arrived. It has an emu bush (front) a westringia (mid) and small gumnut (rear) for honeyeaters and bees. The large dried gumnuts are great for craft, or just to have around the house for decoration:

I'm sure the ones which are left on the ground, turn into great humus eventually and make great hidey places for bugs and microbes too! Which is one of the reasons we're actually dropping the branches to make swales, rather than burning them off which seems to be a common practice in this area. Even though natives tend to decay slowly (especially eucalypt material) it's important to note we're not growing European trees here. The aim of this orchard is to feed the natives, which includes insects and microbes - burning off plant material, only robs the soil of it's evolutionary entitlement.

Felled acacias and eucalypts
but the dark-brown bark of the ironbarks remain

It's part of the reason we've also left some natives in this belt too. Endemic to this area (or use to be before land clearing and development took over) were ironbark trees. I love these trees with their gorgeous rough bark. The cockatoos love this tree for the very same reason! It's a great hidey place for bugs and when you've got a beak built like a commercial sized nut-cracker; you've got no problems stripping back the bark to get at them!

We are looking forward to seeing how this bush orchard develops and the interaction the native plants have on the soil. We've planted straight into natural dirt here, with only compost and gypsum added to help with acclimatisation. We hope to see the grass recede eventually to the shading of the natives, creating natural humus that only this landscape can appreciate fully.

Our garden bandaid over a massive cut and fill site

In stark contrast however, look at this area in-front of our house: the garden is maturing slowly to keep the soil in place, but it's not designed to feed natives. It will be a pretty garden and it has multiple purposes (all vital and functional) but the inputs in this patch of land were enormous!! First the earth mover which cut the land for the house to be built, then we had to erect the retaining wall and plant out; now we're tweaking the drainage to avoid water wiping out the garden again, like it did in the horrendous floods we experienced late last year and earlier in January.

Compare that to our efforts in this bush orchard, and it's laughably minimal. We've only had to remove a few spotted gums and acacia saplings (by hand) mown the grass in the growing season and mulched with bark. Eventually we won't have to mow this area at all - the system will look after itself.

Which is why Dave and I are looking forward to seeing how this experimental plot goes. We don't mind working hard, but we also don't like working against nature either. Been there, done and doing that, LOL! We hope to learn a lot from this new form of gardening, so that we can actually grow better European food trees as well.

There is much to learn from our native predecessors.