Sand Dams the Permaculture Way
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- เผยแพร่เมื่อ 1 เม.ย. 2024
- Sand Dams are a little known and highly effective way to store water in dryland river systems that lead to increased perennial stream flow, allow for productive forestation of stream banks, recharge groundwater tables, stimulation of wetlands and prevent rivers eroding downwards.
If you want to learn more about Permaculture Design please go to our website www.permaculturesouthafrica.co.za as well as more videos and info on our permaculture farm or attend one of our Permaculture Design Courses, details of which can be found there. Thank you...
USGS TH-cam channel has a video on very similar small rock dams on an Arizona ranch that has had a similar effect as your “sand” dams.
PS - parts of USA have benefited from the reintroduction of beavers into areas they have been eliminated from. Beaver dams have been very good at retaining water and preventing erosion
PS2 - Impressed your designs can survive those high river flows.
Absolutely spectacular video. I really appreciate seeing the footage intercut with actual high flow. Amazing how much silt is carried in the water. Really appreciate your understanding and sharing of all this knowledge. Thank you.
Thank you James
Love Your Idea is the most approachable and sustainable I have seen
Thank you...
You aren’t an environmentalist or Stop oil person. You actually believe in conservation. Areas with less rainfall were always a problem, you are showing the way how plentiful of rain should be used: you are awesome.
Thank you...
@@kenttahir.cooper5282 Thank you. 🙏🏼
А я противоположного мнения... Уважаемий афтарчика видеосика слишком много бла-бла-бла и никакой конкретики и никакого действия... Но ето поправимо ... При первом же проекте, он может поработать у меня общим работником и понабратся практическим опитом ... Далее его видеосики станут весьма короче и весьма полезнее обществу ...
Excellent video. I am really impressed by the amount of work you have done. And to be able to work with such a huge flow of water, wow! We have two seasonal creeks on our property too -- I will walk them and think about gabions. And thanks also for telling us the size of your gabions as well as reporting the importance of protecting the embankments. This was a very interesting and useful video.
Thank you. Gabion work is heavy graft...
fantastic to see that water disappearing into the ground, a really great illustration of how the water is being stored in the silt fields, just out of sight!
Thank you...
Wonderful, the most successful use of gabions I’ve seen that can handle the short yet catastrophically torrential floods of dry land areas, and sink the water for year round availability.
Wonderful, thank you. I am going to do this on a small scale on land I just bought. Hello from Southern Oregon😊
Howzit... All the best with your project.
Nice one. Very good engineering. At 26,55 we see the production terraces, and the comments about not having the structures too high in order to not break the banks. Yes But But the big But. In a flood event it is possible to have a sluice or swale outlet to irrigate a field , a production terrace, or soak a flood plain. For example, (in rough figures) if 10 megaliters goes past your property, half a megaliter gets diverted onto a flood plain or production terrace gently,,,,then the sluice or swale is shut off. or it could re enter the creek system later downstream. There's another level of engineering available here, maybe your already doing it unseen in the video.
Sure, that can work, depending on the context of the river drainage line in relation to the terraces that will allow safe engineering. I was able to achieve this on another farm I lived on in the region 15 years ago but the setup was very different to this farm. The thing is that when you get these big flood rains there is so much water flowing off the slopes into the swales anyway and the production terraces get a huge soak. With rivers, often you can get more rain upstream so the river will pump down, even though there may not be that much rain locally, and that is when a diversion system will work. The sand dam then needs to be upstream from the swales or the terrace system, with a canal or pipe drifting off from the wall of the sand dam onto the terrace or swale system. Our context here does not allow for this, but it is possible in the right setup. If there is going to be a mega rainfall, then you can, close off the canal or pipe and open in smaller flooding events. There are so many possibilities with good design, it really takes good observation and then fine tuning after the system goes through a range of different events...
Hi. Hydrology and geography of watershed must be considered before any erosion control/ dams are built. I absolutely agree type of vegetation must be integrated into whatever type of erosion/ water storage systems used. In your environment sand dams are great option- for me- not so much- 1 rock dams, log/rock rundowns, appropriate vegetation with careful management of tracks with rollovers, grazing, tarmac water runoff, and siting of dams.
For sure, observe and interact, the first principle of permaculture design and context is everything...
Very nice, and thank you for sharing! 👍
Thank you...
Excellent walk-through, and you can certainly see the results! I'm a big fan of building beaver dam analogs simply because I have more woody debris than rocks. Considering the amount of water you get coming through... rock is probably the better choice! Have you put gabions up at the very highest point on your property?
Howzit Tahir, awesome timing on your video,planning on doing the same by us,your place is looking fantastic dude, greetings from Kermit
Howzit Kermit, shot man. I am working on another river training vid, this time on gabion groins...
Looks like you are following in the steps of Tony Coote and Peter Andrews and the work they did to Mulloon Creek. However, you are keeping most of the water hidden which is better in an arid environment.
Yes, especially in very hot dry environments where evapouration is a huge factor, which leads to salinisation of surface water...
Great tour of your system #sanddam system!
Haven't finished yet. Are you clearing the Silt (Rock Dust) and using in plant, crop, and/or pasture. This also allows you to capture new Silt and move it out of the river bed.
A filled Silt trap is no longer a Silt trap... it just runs past it in the future.
No. The river silt is not fertile, it is very sandy. My soils in the fields are extremely fertile loams. I manage soil fertility in place by integrated design between rotating livestock, legumes, subsoiling and effective guild formation. Moving around soils is not effective or possible on an agricultural scale.
Super video. Well narrated from an informed and educated presenter. The volume of water during the flood events was breath taking. It leads me to ask how much of the upstream catchment area is actually your land? If it is all your land, then is it possible to catch more of the water where it falls (swales, leaky weirs etc) to prevent such volumes reaching the valley floor all at once? Best of luck with your future endeavours, as the earth needs people like you!
Thank you... Yes most of the catchment is on our farm, however it is far too steep and wild to do any form of earthworks on, thin rocky soils, etc... In desert environments, flood surges are standard as vegetation cover is not dense. The best you can do is to encourage the growth of perennial grasses to provide as much land cover as possible, using livestock impact where possible. But at the end of the day the flood surges are just something you have to design for wherever you possibly can. In more gentle landscapes swales, riplines, berms, diversions, pocket ponds and earth imprinting will most definitely make a huge difference, as they will not only slow, spread, sink water but encourage denser vegetation cover, which is really the ultimate way of retaining run-off.
fascinating stuff! i can only imagine an aerial view! id love to see a comparison with a comparable area that hasnt been managed like your area
Howzit. I will be doing a new drone flyover vid in the next few weeks...
👍😎✌️
thanks
If you put a checker board of gabions on top of the silt field that would slow the flow down and reduce the destructive capacity of the water surge.
The water surge is never a problem if the gabion walls are made in the correct manner and located well. The destructive forces of the water are always in the center of the stream course and start having impact where the river bends, as it starts to undercut the banks. I am busy with a video on gabion groyns, which addresses this issue.
A question, after the backside of the gambion gets filled with silt and forms a level field. Can, or will you, then add or extend the gabion higher allowing more silt to build up?
Hi... Good question... It all depends on how high your stream banks are. If they are really high from the silt field then you can add another row of gabions, as you do not want the river breaking its banks. You need to step them back so you do not create a sheer wall, which will cause high water impact at the base of the wall and it could undermine it. Only make the sand dam as high as your stream banks will allow...
FYI- Sand dam project
People should tame the wild as much as possible.we have plenty of water we just need to catch it
Where is this land please?
Its in South Africa, in a semi-desert called the Little Karoo...
@@kenttahir.cooper5282 thanks for your answer and by the way brilliant video
Just a note, grain size doesn't determine water holding capacity, If all the grains are spherical, and of similar size they will hold the same amount of water, no matter the size. Mixed grain sizes hold less as the small grains fill the spaces between the large grains and reduce the water holdng capacity, to the extreme where very fine clays will close up the voids completely.
If you have coarse sand it will hold more water as there will be more pore space between grains. The smaller the grain, the more compact the medium will be. River sediment is a mix of all sorts of media, some with lots of clay, others with gravel type media and others with silt/sands...
@@kenttahir.cooper5282 It depends on the sorting of the grains. The size is irrelevant. A box of ping pong balls has the exact same ratio of pore space as a box of soccer balls. A box of mixed soccer and ping pong balls will have less pore space.
@@stevesavage8784 Thais fine Steve, I have no problem disagreeing with you. You are never going to get the same size grains in any river, they will always be mixed and never be spherical. However a general larger and courser gravel will hold more water, I have seen this directly with my sand filter systems on our natural pool. The really finer grain materials hold less water, are compact and have less pore space. This is a direct observation... Courser material will also drain/infiltrate quicker to the clay or rock base of the river, while finer material with higher clay/silt content will run-off more before infiltrating, however will retain moisture for longer if there is not impermeable base to the system. Context is everything.
@@kenttahir.cooper5282 Physics and geometry have their own context. Take some measurements. Sand filters are washed and sorted sands, so they will hold maximum water, but fine sands or coarse sands will hold an identical amount. Sorting not grain size determines water holding capacity.
I’m curious about the construction of the largest gabion sand dam that you showed. I see that on the downstream side it is stepped down. Does it look the same under the silt field like a pyramid, or is each gabion basket stacked partially on the gabion below it and partially on the new built-up silt bed upstream?