Looking for thoughts (and examples if any) of using swale designs to terrace steeper slopes rather than (or in addition to) directing water or storage of. Any examples of using temporary or permanent structures (retaining walls) with swales on larger slopes during excavation and tree establishment ? Have seen similar thread on this forum but wasn't in line with my thoughts here. The image on the following link is a bit dramatic but could a terraced style swale system be developed on this slope ? https://www.comuntierra.org/site/imagens/comunidades/comunidade82_1166.JPG The paddy fields of China come to mind...
Check out the Geoff Lawton latest vid, it's on a very old permie sit in Hong Kong, built on the side of the mountain, lots of terracing, ponding and and working with water. https://www.geofflawton.com/fe/77209-re-greening-a-mountain (you might have to register for that link to work, it's just an email address, no spam).
Thanks, Pebble. I did watch that on Saturday but since it was established decades ago I didn't see much in the way of raw ground work. Or specific advice on implementing swales on such slopes.
Hi Andrew, That was just an image I pulled off the net. I don't see the full aspect of the block in question until later this week... but from the observations i have made there is a significant slope... the image is just an example to show roughly what i'm thinking. Have you seen examples of swales on slopes such as this - generally speaking?
One attempt at steep slope swales (s^3, ha!) https://orkoskey.com/2013/06/23/experimental-permaculture-steep-slope-stabalization/ Maybe not so do-able for large areas. A discussion on the subject: https://www.permies.com/t/17423/permaculture/build-swale-steep-hillside Did you find this? https://forums.permaculturenews.org/showthread.php?349-Swales-dams-and-steep-slopes I think you are prudent to consider all the ramifications of steep slope earthworks.
This is a very interesting question, as I've had dealings with steep slopes in the past. Water saturation on steep slopes greatly increases the rate of "slump" and can lead to catastrophic mud slides https://news.nationalgeographic.com/news/2014/07/140722-oso-washington-mudslide-science-logging/ Retaining water in the soils of your photo might not be such a good idea. Mollison talks about steep slopes in the earthworks chapter of the PDM. Sepp Holzer may be the undisputed king of steep slope earthworks in Austria ... he seems to favor benches and limited terracing implemented over a long time period. YMMV.
if you get a chance sometime look for a program on Maccupiccu (not sure of the spelling : ) ) where they show how it has a very well planned system of soaking and and draining the frequent rains. very interesting. i think National Geographic did it...
Every single year I have had mudslides going across the road here. I haven't even set up a single swale on the side getting mudslides. I haven't even touched my steep slope area yet. Holzer made roads that he called terraces, he makes no false hoods about it in his book and videos since it got him around government red tape.
Swales with ridges for tree planting: https://www.nzdl.org/gsdlmod?e=d-00000-00---off-0fnl2.2--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0--4----0-0-11-10-0utfZz-8-00&cl=CL1.1&d=HASH01c384e36cf9387c55ceb499.9.3&x=1 Some good info here (long document from the Peace Corps) https://www.nzdl.org/gsdlmod?e=d-00000-00---off-0cdl--00-0----0-10-0---0---0direct-10---4-------0-0l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-8-00&cl=CL1.136&d=HASH013e8d1a442c5a625761db09.2>=2
Tassie steep swales Gday Andrew I was in tassie a couple of weeks ago around ringarooma there was a long aqua duct called the race I was interested to see that it collapsed with a massive mud slide and closed. This was a compacted ditch not a free flowing Swale. I think the soil is very movable and susceptible to slipping. The 20-25 degree slope would be my rule. The net and pan mention in molisons manual might be better
I am familiar with the location of your link...as I live in Oaxaca, and have visited this site many times...and know Oliver, the manager of the project....are you working with INSO? Are you still in Oaxaca? I'd be curious to hear of any responses to the question you posed in this forum. You can also contact me at [email protected]