The Gordon Gnohm

Play along at home, read Future Farmer in The Braidwood Bugle every Wednesday. 

Passive Land Hydration Pt 1 Basic

Another rain event blessed us this long, hot, dry summer. The garden hasn’t needed my attention except to munch, and the growth from the Skywater is amazing. The land hydration offered was significant, if you had the systems in place. Otherwise, the water probably left your place quickly and took some of your topsoil with it.

If you are like me, you were out in the rain checking the waterflow. If you didn’t get outside, the mulch and twigs riding in the solution will leave you some telltale signs, so check it out.

I touched on this in ed 184. Water is led by gravity and always falls downhill, even the slightest slope will create running water. Passive Land Hydration can only occur if the earth is permeable and contact lasts for an extended period. 

The Might of Water

As heavy rain runs down your slope it picks up speed, and volume, creating an unstoppable force. If the land has no abatement systems like grass, reeds, fallen trees or hedge rows the water will remove topsoil, create erosion and deposit sediment along the way. All the time trying to find the fastest, simplest way downhill.

After the fires, our hills were devastated. Fallen burnt trees everywhere. Topsoil covered in ash. So, when the February rains belted down, most of the ash and topsoil ended up filling the dams at the bottom of the hills. But not everywhere on the property.

Fortunately, while we were extinguishing spot fires, we were turning fallen logs on contour. These simple ledges, starting at the top of the system, created places for sediment to get trapped and water to soak. 

Where to Start?

The top of the system is the best place to start, the water cant build up any speed or power. It is easily stopped and spread across the hill, before gently overflowing into the next log ledge. The sediment stayed behind and filled gaps creating a small earth bank for water to soak and nutrient to build. 

The logs are now hard to spot as the grasses and groundcovers have capitalised and smothered the space. The areas of exposed rock are now becoming somewhat colonised by grasses covering the rocks in a living mulch, in turn creating more topsoil. 

Strange Things

Ive been watching my neighbour remove all the fallen timber from his hillside. The effort is incredible. There are many large piles of timber along the front of his property. If only he had turned them on contour where they laid.

Im sure he will burn all that nutrient when summer passes, just like men have done before him. If he just burnt the piles at the top of the hill, the land would receive some benefit.

The chances of grass growing on the now exposed rock is slim at best. If only he had approached his block with a mindset to protect his precious topsoil. 

All his toiling has removed resistance to water flowing downhill. Landcare have a well established program of creating forests on top of hills, so its strange to see the opposite happening.

Keep the Logs

Turning the logs, rather than removing them, creates sediment traps on the hill. Fallen logs and branches provide mulch, as described in ed 177, Eucalypts are masters at it. Wet logs create better habitat for microbes and fungi to decompose the carbon and create more topsoil.

Fallen logs break down over decades and create amazing building blocks for topsoil. Decaying logs have more life on them than a living tree does, so removing them is stealing habitat from your ecosystem, causing erosion problems and reducing biodiversity.

We have plenty of rocks on our hill, so we put them to good use too. Turning logs and rocks on contour is the simplest way you can start Passive Land Hydration at your place. As a remediation technique this is the first place to start. It’s a simple cost effective way to capture and store your Skywater, reduce erosion and improve productivity on your patch of earth.

Finding Contour

Over the years I have become a human laser level, reading landscapes with reasonable accuracy. But it wasn’t always that way. I have used a few different types of tools to get there and plenty of saddle time. I first started with a trusty screed level. Simply accurate but only over short distances.

For larger distances I tried water levels. Two stakes with a clear hose in between. Good for medium garden areas limited only by the length of hose. Difficult to use over multiple days as the water evaporates and requires recalibrating. And don’t let them fall over.

A traditional method is to use an A frame with a plumb bob. The frame can be walked across a landscape with ease. It takes a bit to get the hang of the swinging weight but can be constructed from found objects. 

In the 21st century laser levels are readily available, they are cheap, very accurate and can be used over large distances. They are my preference.

Slow it, Spread it, Soak it

My mission with water is to slow the flow, starting at the top of the system. By the time a powerful rushing flow gets to the bottom of the system there is no way to stop it. Anything in the way at the bottom of the system will get washed away, just like happened on the Cooma Road project over the holidays. And many roads in the region before.

If we have the foresight to slow the flow, we will need to spread it on contour so that the land is hydrated evenly. If only a small amount falls, it will be shared across the landscape.

Spreading water on contour reduces the power of the flow, as there is no fall. The overflow can occur in a space that is advantageous. Perhaps through reeds, grasses or hedgerows. This watershed will flow across the land and get caught downhill, to slow it and spread it again. 

Continuing this technique all the way downhill will accommodate small events, holding the water on your property a short while longer. The result is less erosion, more topsoil, and the plants nearby will benefit greatly from the nutrient and water load and your damp timber is less likely to burn in a fire. 

This Basic Passive Hydration System is the simplest and easiest way to get started. The systems can become far more complex and hold much more water as we move toward the ultimate example. Each system will work for you, in the backyard or the paddock, even if you are not at home. 

Next Week

The evolution of this Basic Passive Hydration System is to bring on the machines, but to disturb the soil in the smallest way possible.

Every day is a school day.

Stay awesome,

The Gordon Gnohm

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