Darren J Doherty

Thanks all for your wonderful questions this past week and to Cassie and Paul and the Permies team for the opportunity.

I'll now be off this site until the next chapter (3 Water) is released.

If you want to catch up with me and our broader network then please go to the Regrarians Facebook Group.

Thanks again and all the best,

Darren J. Doherty
Director,

Regrarians Ltd.

•CHECK OUT Regrarians.org
•BUY the Regrarians eHandbook Chapter by Chapter
•WATCH the 'POLYFACES’ documentary trailer

Good question Sam,

1. A channel of 1:200 would only be in highly porous ground – such as many granites — generally we go between 1:300-400 with our water conservation channels or gradient roads for catchment purposes. We do go to 1:100 on kerb and channelled roads when we have other features that need to run at the same gradient and therefore at an equidistant offset from that road — this particularly applies to stormwater and sewer pipes, the latter having a standard gradient of between 1:80 and 1:120.

2. With regards managing channels with Keyline Geometry — you'll very unlikely have a complete match there, however as compared with contour plowing you will have equidistance and the default fall to ridge in the system in between any lines above and below. The same applies if you have a contour swale above and below — you can still run Keyline Pattern Cultivation (KPC) oriented rows or plowing lines in between these, only you will have some areas above and below this KPC-treated area that won't match up.

3. I don't see any reason why you would do a road on contour — it would only serve to potentially undermine the road stability — of course we build roads on dam walls however we typically have 1m + of distance between the saturation zone and full water level and the top of the road. Most road gutters are not 1m below the road surface. If you are stuck on building a road on contour then you'll be investing in plumbing to get rid of the water that would otherwise saturate the road base and cause the outcomes that follow reaching liquid limits.

4. I'm not completely sure on this question however what I would say is that there is are gradients of both row fall and trajectory which one will establish according to each site. That said I am very satisfied that the outcomes in most cases of proper KPC is that even at quite steep gradients, runoff is severly mitigated even in some of the biggest events and rolling rainfalls. With regard row trajectory every implement has a comfortable turning radius and operating angle of slope. Find these all out, see what you're comfortable with, do some testing and off you go.

Thanks and all the best,

Darren

Thanks Luke,

Appreciate your kind words.

The 2016 World Tour has just been announced – you can take a look at it here.

Thanks again and all the best,

Darren

Thanks,

My consistent approach Dan, and you would have seen this quite consistently, is that the first matter to take care of is the establishment of your context and that of your landscape. Secondly another consistent message I've given is that its important to look at all of the means by which an issue might be corrected. Thirdly, and I think this is particularly important, is the treatment you are looking to use addressing the cause or the effect? In many cases swales and other treatments (including KPC) are used to address the effects and don't necessarily address the root causes. For me that is a much deeper question and why I suggest starting with considering and establishing personal/enterprise and landscape contexts ahead of applying money and energy at the outset.

Cheers,

Darren

Thanks Aljaz,

I'll have a look at the site of your surveyor friends – always interested in the means by which we can reduce the cost of accurately surveying landscapes – even though the cheapest way would be to have our respective military's supply this information widely!

Its hard to describe what to do with regards dams and roads so I'm going to prepare a few diagrams that I hope will explain things better:









The 2016 World Tour will be all about the new REgrarians 10 (X) day open consultancy ('REX') – you can read all about it here.

Thanks and all the best,

Darren

Thanks Kelly, Corey and Gary,

Its all very interesting this stuff — I am a big fan of the book, 'Vegetation and Soils – A World Picture' (Eyre, 1962) as it confirms and expands on what many of us would already suspect — the relationship between the kind of vegetation communities and the behaviour and characteristics of soils as a result.

A simple example is where we have the same ridge — same parent geology, same geomorphology, same agricultural history right up to today. We apply a number different treatments to strips of this ridge. On one we put swales and plant a deciduous forest, on another we do the same only with conifers, on another we KPC and establish perennial pastures, on another we KPC and plant the two forest types and then then others we let nature take its own course. Now lets assume that we managed each of these with best practice — we apply ProSilva principles to the forestry systems and Holistic Management Planned Grazing to the pasture — however did nothing to the natural site.

Lets do this all for 15-20 years. What do you think the soils of these different strips will look like now? How will they behave? Further to this what is the runoff coefficient of each vis a vis the infiltration rate of each? What is the return on investment from each?

Ultimately the ongoing infiltrative effectivness of each of a swale is completely dependent on the management that continues after construction and the chemical/physical characteristics of the soil in the first place. Build your swale out of dispersive clays and it will reach its liquid limit quickly, lose porosity and go to cement when dry. Heavy reactive clays will shrink and swell as they do and water will come and water will go or water will stay sitting for a very long time. And so on it goes.

But yes Corey, KPC between swales is a good idea if it fits with your holistic context.

Cheers, Darren

Thanks Aljaz and also for your kind words,

First of all thanks for having the sensibility to understand your site and look at using site-appropriate treatments rather than just applying carte blanche!

Secondly, I have an old colleague from my days working for Mars Inc. in Viet Nam who is Slovenian and she was always telling me how I must go there and how beautiful it is etc. We'd love to go to everywhere in the world and Slovenia is definitely on the list!

So straight to your questions:

Starting point — there is not much point using Keyline geometry if you don't have a good contour map to manage your design on first. So often there are landscape anomalies that require some advance desktop planning if you are going to do you and your system justice.

But yes the lowest ridge contour is often the best place to start and yes find the apex of that ridge and go from there.

Following is an instruction I gave on this question in our Regrarians Facebook Group just the other day:

"...In the absence of a proper survey having been completed I would stake a series of contours over the site and paint-mark (or ribbon) the stakes different colours that alternate from one contour to the next (2 colours should do) so that you can differentiate between each marked contour.

Then start marking out the guideline offsets again using alternate colours (though different to the contour colours) and then compare these offsets to the contours. You're doing here what we'd normally do on the screen following a detailed contour map.

If the guideline offsets are going where you want them to then go back to the guideline and adjust it and try again (and again!!) until you're satisfied..."

Years ago i turned up at a clients property and his son had just done a Permaculture Design Course with a Prince and King ( ). Anyways he was setting out a 0.25 hectare orchard following the contour as per the logic recommended at the PDC and had put stakes in the ground following the different contours and strung string between each stake — so he had marked contour lines effectively. It was diabolical from a land use and access perspective, no equidistance, some rows were 1m apart and some 10m apart such were the shape of the contours on this hillside.

So with this I grabbed a bundle of stakes and picked a lower contour and then put a stake in lower on the ridge curve and higher on the valley curves. Then I used the tape and went 90 degree and marked out a series of additional rows parallel to this lower line. Then I referenced these against the contour and we had to tweak the lowest line's shape in order to get the desired effect i.e. rows gravitating to always fall to the centre of a ridge. We even strung line between the Keyline pattern stakes just so the client's son could get the picture — which he did and shook his head for the logic and genius that is the Geometry of Keyline.

I do hope that this all helps and please let me know if you have any further questions.

Cheers,

Darren

Thanks for the note Kelly,

I have used the terms that P.A. Yeomans used to describe his water harvesting features. That is the following:

Water Diversion Channel
Water Irrigation Channel
Water Conservation Channel

Cheers, Darren

Thanks for your question Gary and also for reposting too.

The swale has become an almost ubiquitous feature of every permaculture-inspired landscape. I seriously question the notion of using any earthwork-based treatment ahead of considering more passive treatments. I also seriously question the sense in applying treatments that, if one were to apply the appropriate due diligence, are just not necessary.

Following are a number of treatments and scenarios around your question:

1. The water cycle is best restored by having the raindrop intercepted upon impact with the land surface by some kind of ground cover. Plant leaf surfaces are the best surface to encourage as is leaf/plant litter etc. Livestock impact, particularly that of the heavier ungulates, is another means of increasing infiltration.

2. The placement of livestock on a landscape at high density for short periods is well established as being a means by which infiltration can be enhanced. Some people use mechanical soil 'pitters' or 'imprinters', others use the hooves of livestock to do the same thing.

3. Surface cultivation is another means by which you can increase infiltration rates. In humid landscapes it is difficult not to have an array of plants establish themselves on a landscape even after years of continuous cropping. You can accelerate this succession by sowing seeds of your chosing. You can sow these seeds using the Keyline Pattern Cultivation technique, increasing further the interception rates and potential rates of return.

4. Subsoiling is another type of cultivation. When done following contours or especially when done using Keyline Pattern Cultivation (KPC) it radically increases infiltration rates AND like the methods listed above does so across the whole area treated.

Now to look directly at the two treatments (swales and KPC) often compared I have developed the following comparison:

I've calculated the cost of KPC at $0.02/m2 (at $100/hour & 1ha/hour). If you are plowing to say 12"/30cm depth at 1m spacings then that equals approximately 375m3/ha of new air space (calculated at 0.5 x plowed volume) & therefore increased water space in a plowed soil. This is the equivalent of 375,000 litres (97,500 US gallons) of water stored at any given time before gravity/evapotranspiration gets to work. This is equivalent to a 37mm (1.45") rainfall worth of capacity/hectare.

Given the nature of the water cycle and the significant variations of water movement in landscapes due to soil chemistry, biology and physics along with the gravity & evapotranspiration the retention time of this rain (or irrigation for that matter) is going to vary enormously and so therefore difficult to apply a general metric to.

A typical permaculture-type swale (on contour) might be spaced at 20m spacing (@5 x 100m swales/ha) and be 2m wide on the embankment and 2m wide on the cut with 0.5m of depth giving an earthworks fill volume of 1.5m3/m of swale. At 0.5 x fill volume this is 750l/m3 of water or 375m3/ha. The ditch itself is usually not that permeable in a swale (unless its in heavy draining soil types) and so this will hold 1500l/m3 or 750m3/ha of water. In total this is equivalent to 112m3 water/ha or 112mm of rain/ha. At $2/m3 excavation cost this equals $0.75/m2 ($1500/ha) to cover 0.2ha/ha

Now to compare apples with apples:

A swale system that would equal that of the total water volume harvested by the aforementioned KPC would be 165m long and still cost $0.75/m2 ($495/ha) to cover some 0.066ha/ha.

To repeat the KPC costs $0.02/m2 to covers some 0.5ha/ha (@ $100/ha)...

Even after the 3 usual passes we are still way ahead and have covered the whole hectare not just 0.2-0.066/ha + perhaps 30-40cm plus of soil (our results at 'Dehesa Felix' Mills Rd, VIC, AU and other places) and not a permanent incision in Gaia in sight…

At our place 2 year ago we had 75mm (3") rainfall event over 1 hour. This is one of the highest totals we have experienced in the region. We have marine-based Ordovician (485 million years BP) sediments which are class 1-2 dispersivity and quite sodic. Following our treatments using KPC we had zero runoff off of the effected areas. Our neighbours who are set stocked and not managing their soil surface in any way may well have experienced more than 80% runoff during that event – with much of it coming to our place and our dams! All good except for all of their manure and detritus coming our way too as this event effectively scoured clean the soil surface.

This is one of many instances we have experienced where the dramatic increases that KPC has had on radically increasing infiltration rates.

These relatively shallow surface treatments are not a permanent earthwork like a swale or water conservation channels, gradient roads or the like. However they are passive and they are comparitively cheap.

Thanks and all the best,

Darren

G'day Gary Huntress,

Thanks for the note.

Could you please do me a favour and ask that query in a new thread so that it doesn't get lost under this heading?

Cheers, Darren