Comments on: A Guide to Back-Flood Swales

By: vivek zade

vivek zade — Sun, 21 Aug 2011 10:58:31 +0000

Good material document .useful to solve the problems

By: Anji

Anji — Tue, 21 Dec 2010 02:17:34 +0000

Fantastic work Cam, good on you for making the time to put it together and get it out.

By: NIck Huggins

NIck Huggins — Mon, 20 Dec 2010 09:08:54 +0000

Great Work Cam.

You know, there’s a book for you to write about this in your spare time.

Talk soon mate.

By: eric seider

eric seider — Mon, 20 Dec 2010 02:26:29 +0000

-
Apparently Design and construction of small earth dams by K Nelson is out of print. And I haven’t been able to find any copies available online. Anyone know where to get a copy or a digital download feel free to share.

cheers

By: Nick Ritar

Nick Ritar — Sat, 18 Dec 2010 21:13:22 +0000

Great article Cam.

We have a PC120 excavator arriving tomorrow morning to do some dam repairs here at Milkwood, but now you have me thinking about what else he could do to our swale/dams/shams/swams.

Apart from the dodgy dam, everything else here has held up pretty well during the recent 1 in 50 (perhaps 1 in 100) year rainfall event.

Looking forward to you teaching water on our upcoming PDC.

Thanks for the excellent information

By: Geoff Lawton

Geoff Lawton — Fri, 17 Dec 2010 10:09:10 +0000

JBob if your water table fluctuates between 60 to 0 inches deep you can create ephemeral chinampas that will become more permanent and less ephemeral over time and after about 7 years they will be a full saturation and permanent in a completely transformed landscape.
Swales create perched aquifers of damp soil when installed and well planted to hardy pioneer trees in large level plains and they do not have to be very deep. On the original greening the desert project in Jordan the swales were just over 2 meters wide and half a meter deep on the back cut with the mound being just half a meter high above the original soil level. On 4 hectares (10 acres) we installed 7 swales with a total length of 1.5 kilometers with an average rainfall of 150 mm (6 inches) and after 3 years we switched the drip irrigation water off on the pioneer trees and it has been switch off now for 7 years and those trees are thriving on the swale in put water. On larger properties you can create much larger swales in dry lands, evaporation reduction through water infiltration, tree shade, wind shelter by trees and organic matter additions from trees plus condensation drip all play a part, nothing is insignificant in good design recovery of dry lands.
Village Homes in Davies California is a classic example of the long term effect of swales where they directed all run off water from the suburb to the swales green ways common areas and measured the rehydration in the soils and got 1 meter the first year 3 meters the second year and 5 meters the third year and after that there is no point in measuring because you can grow anything you like within temperature range when you have 5 meters of damp soil in drylands.

By: JBob

JBob — Thu, 16 Dec 2010 18:29:20 +0000

Geoff, good point. But it is still called a “swale” if I have to dig 8+ feet down? (To leave at least 3ft of water for the fish in dry times.) I just thought that would be called a “pond.” And runoff capture doesn’t matter, I reckon, in the middle of hundreds of square miles of level plains. The water table will do it’s own thing no matter what I do.

By: Geoff Lawton

Geoff Lawton — Thu, 16 Dec 2010 15:07:28 +0000

One of the great things about permaculture is that is and ever evolving system towards a richer more diverse polyculture of production.
At Zaytuna Farm we are using grazing animals to prepare and condition country and facilitate this evolution and as spring waters emerge at the surface between our swales it leads us to increase our aquaculture capacity which is 30 times higher in protein production to area used than grazing animals. We now have 13 dams and our grazing animals are increasing in quality production although they are now on smaller grazing units with longer rotation cycles.
It is just getting more interesting and more diverse in production all the time and swales would have to been one of the main frame component patterns that have and continued to contribute to that on going event.
Every earth works course we install more swales to help people understand these amazing features.
While teaching with Bill Mollison in Turkey just recently he told me of a client he worked for many years ago who really wanted swales on a property in Hawaii but the property was all volcanic highly porous dust and Bill tried to convince the client that swales would not have any effect as there was absolutely no runoff. The client insisted that he still wanted to try to reforest the slopes of the property on contour using swales as the starting point, so Bill designed and directed the installation of 8 swales and the client planted his initial pioneer trees backed up by drip irrigation. The trees grew at a normal expected rate in those conditions using drip irrigation, but as they became closer to being established they start to speed up and their leaf fall and root net started to reduce the porosity of the volcanic dust and the swales started to hold water for a for a few minutes then a few hours after rain events and a humous started to build up in and around the trees and more trees were added and the drip irrigation was used less and less and eventually turned off. With the end result of the whole slope being planted and eventually covered by a productive forest and a layer of high humous soil produced.
Swales still continue to surprise us.

By: Chowgene Koay

Chowgene Koay — Wed, 15 Dec 2010 23:47:17 +0000

Interesting article as always. Always a benefit to have more tools in the box to address various landscapes with an appropriate design.

By: Andrew Carter

Andrew Carter — Wed, 15 Dec 2010 23:31:49 +0000

Great article Cam. I like the depth of the analysis into swales. I’ve often met people who think swales are appropriate in every situation (I call them “Swalians”). The article shows how swales can be modified to make them appropriate in a range of situations. Thanks Cam. How about you do an updated permaculture text?