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Here's the short version.

Clever CGI showing the principals he is explaining, but I've been researching gabions for quite while now and I've yet to see many videos of mature systems based on them, or even systems at partial maturity.

There are some videos online of gabions being constructed, and even of some with a layer of sand/silt build up behind them after a flash flood or two. It is a shame he has relied on CGI here rather than exploring sites where this is working.

I am a supporter of geoff lawton and all the amazing work he has done to further the practice and application of permaculture at a global scale. I am a student of his, a PRI registered teacher, and practitioner applying many of his strategies and techniques. I state all this to put my critiques into context, because I don't want to take anything away from the enormous contribution Geoff and PRI have made to Permaculture as a movement, to improving many peoples lives and livelihoods, and to inspiring us all to take action following the Prime Directive.

I am not in favor of gabions or check dams in most contexts. they may be useful in specific contexts (although I cannot think of one off the top of my head), but in general are a misplaced pattern, particularly in a channel setting. Over the past 20-30 years many installed gabions have failed often reverting to the original condition or causing more damage. David Rosgen calls them 'time release sediment capsules' and there are other more appropriate strategies for managing water and sediment in both a channel and upland setting. For a more detailed discussion of appropriate strategies and techniques, I encourage everyone to look at the discipline of fluvial geomorphology, modern erosion control methods, the work of David Rosgen, Bill Zeedyk, and Craig Sponholtz. Using these methods, there is actually more sediment and water stored at a landscape scale and stream channels and other eroding landscapes are able to slow water and sediment at a rate in balance with other processes. No method is perfect and they are all evolving their work within a science based framework.

These strategies and techniques more appropriately fit the patterns of streams and water and sediment process in landscape, so we are mimicking nature more accurately. Water is a powerful and durable force in the landscape which will humble us every time until we develop an appropriate respect and pattern.

just my thoughts and opinions.

some links:
David Rosgen
http://www.wildlandhydrology.com/

Craig Sponholtz
http://drylandsolutions.com/
http://floodwateragroecology.com/blog/uncategorized/10-guiding-principles-for-watershed-restoration-regenerative-water-harvesting/
http://drylandsolutions.com/Erosion_Control_Field_Guide.pdf

Article on Bill Zeedyk's work by Owen Hablutzel
http://permaculturenews.org/2011/07/14/let-the-water-do-the-work-induced-meandering-an-evolving-method-for-restoring-incised-channels/

Neil - thanks for your post. This work is one of discovery and it pays to have options - lots and lots of options.

I was just at a talk by Brad Lancaster this past weds evening and he showed a check damn (dry laid, not gabion) that had deteriorated over time and talked about the work Van Clothier does with stream restorations in drylands using "one rock dams" - interesting work!

Jennifer - Brad Lancaster is my homie !! He came to Vegas last year & we hope to have him back this year ... was the one rock dam just one rock high ? obviously not literally one rock .. tehe ... Larry Santoyo has mentioned those b4

Enrique - Brad is MY homie!!! We will have to arm wrestle over this.... (be forewarned - you will LOSE! Mwahahah!)

A "one rock dam" is literally "one rock". However, there are usually a series of them together.

From Van Clothier's site "Stream Dynamics": http://www.streamdynamics.us/resources

explanation of one rock dams, zuni bowls etc...

I finally found a good explanation of these - not a huge amount of info out there in the public domain.

iam planning on installing some gabions at the beggining of some property i will be involved in the design of this summer and will be placing them in a draw or two, judging by the view of the landscape i think its safe to say that these draws recieve a very large amount of water very quickly during sudden, fast rain events and the purpose of the gabions would ber to slow this water down, my question is, is it best to start with the largest boulder in the first gabion to take the hit for all the following gabions or would it be wise to use smaller stones at first and work towards larger one so that if the smaller ones were taken out then the larger ones could still stop them?
there are no trees "upstream" of where the water would be coming from, just sagebrush and grass but there is definitely the potential for a lot of water at once

what are some other ways to strengthen Gabions?

No real clever stuff to add to this - just that there is a small drain beside my house that I was worried about it undermining the ground that my garage sits on. I had been (foolishly) keeping the channel nice and clear in the hope that all the water would just run away and leave me alone, but of course that makes it carve deeper. So with a few judiciously placed rocks, I've checked the stream at a couple of points, and it's slowly depositing silt and raising the level to a more manageable bed. Maybe it's just a human thing - we like to see nice unimpeded flow - we have to break that addiction.

my question is, is it best to start with the largest boulder in the first gabion to take the hit for all the following gabions or would it be wise to use smaller stones at first and work towards larger one so that if the smaller ones were taken out then the larger ones could still stop them?

If the arroyo receives a large discharge you want all large rocks. Largest at the thalweg and channel center. you can use smaller-ish ones at the edges of the channel if it actually connects with the floodplain. This is based on the natural phenomenon of sediment sorting.

I recommend one rock dams in riffles, zuni bowls, log stepdowns, or log and rock stepdowns on headcuts, baffles on bends, etc. Floodplain benching might be an option too. Hard to say exactly where all this would go without surveying the channel and calculating and characterizing the catchment area. Context is the first step, always before technique.

I just dug out this rather old photo which shows the difference in soil height each side of the stone wall that surrounds our property.



I don't believe that the wall was built with the intention of acting as a gabion, but over the decades it has certainly acted as a silt-trap and there is now a marked build-up of soil on the upper side. I'll have to get busy with the camera as there are quite a few places around here which illustrate the effect pretty well.

During the winter rains, water will gush right through this wall in one or two places like a fountain, but I might have to wait til next winter to show you that.

Hello Everyone

I just got a great description of Gabion Baskets also some contexts Gabion Baskets would be appropriate in this came from a discussion in the Watershed Restoration Group on Facebook https://www.facebook.com/groups/384391798391982/ from Jan-Willem Jansens

Here it is

Jan-Willem Jansens Hi Jeremiah, Let me try to add my thoughts to this also, in an attempt to participate a bit more in the conversations. I have hardly ever chosen to work with gabions, but I see where they have their place. Water makes 3-D movements with oscillations up and down (waves) and sideways (meanders); the steeper the slope the stronger the vertical oscillation and the weaker the horizontal ones. As a result, flatter flows tend to meander more and steeper flows tend to cascade more. As far as I've traced it back, check dams, and later, the engineered form, gabions, were developed for steep mountain streams in the alps that typically have a cascading nature. Like with forestry techniques, these stream management techniques were replicated for US conditions in the 19th century. Unfortunately, they were promulgated outside their original ecological purpose conditions, such as in flat, sandy streams (including in the Sahara!), where they often failed due to the stream's meandering, rather than cascading movement. In such conditions, they tend to fill in behind them, get flanked, or undermined due to piping in the sandy bottoms. I have also seen that they can be very lasting in sandy bottom streams, to such an extent that they raise the grade so well that they cause dramatic meandering upstream due to a stream that becomes too flat and drops too much coarse sediment. But that's a design error rather than an error of the selection of the gabion as a technique. However, if used in cascading rather than meandering stream, and if well keyed-in, and designed with a spill way (notch in the dam) gabions may work well, especially where a large, strong structure us needed. They also work well in retaining walls, coffer dam constructions, and revetments, if well designed and properly installed, and if one is not put off by their non-naturalistic look. [JWJ]

Hope this gives everyone a better understanding of Gabion Baskets

cheers
Jeremiah