G'day Allmost all the swales you saw are drains ie compacted banks with fall designed into them
the more modern ones are flatter (plough over) design
they are somewhat effective if WELL designed,the problem being the large volume of water concentrated in a small area
the best thing they do is to get the tractors to drive in the right direction (almost on contour)
Most date back to the 50s the soil conservation service used to promote such activity
proper swales have a lot of potential in these environs or these drainage banks could be converted quite
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easily
A few months ago, whilst driving east along the Gwydir HWY (NSW, Australia), I was taken by the amount of swaling that was visibly taking place in the roadside paddocks. Some appeared to be very fresh, while others appeared to be much older. At the time I had my lap top with me, and when I later pulled up at Gravesend (for fuel and to checkout the old railway station retro-fitted into a radio station) I decided to jump onto Google Maps and have a look. What I saw astounded me. For hundreds of kilometres, farmers everywhere had been swaling. Some of the older ones have been furrowed and cropped over by later seasons of 'straight-line' plowing, but the old swales are still visible. The newer ones appear to be well maintained. For anyone who might be interested in having a look , start at Moree (NSW), where the Gwydir HWY meets the Newell HWY, and track your way east using Google maps with the scale bar set to 500m/1000ft.
If anyone knows anything of the history of swaling in this area - when did it first start, how efficient is it, why have some stopped? - I'd be very interested to know, and I think we could all probably learn a great deal from this area of intense swaling. I note 'barely run' (Cathy) is from Glen Innes (NSW), perhaps she can shed some light on the subject?
Google searches uncover many different applications for swales in this area - agricultural, urban, stormwater retention, flood mitigation, revegetation works - but the results of my searching thus far are thin when it comes to the efficacy of swales, and if we are going to promote swales as a positive practice when it comes to permaculture projects (particularly on the larger scale), we need to have evidence. Obviously I will keep up with the research from my end (early days yet), but would be very intrested to learn, maybe even first hand from someone who is actually swaling in this area.
G'day G
Welcome to the PRI Forum.
Congratulations on uncovering the the old art (and science) of swaling in your district, hopefully you can convince the farmers as to the benefits of swales and Keyline plowing. Concerning Keyline, I presume you have read everything by its founder P.A. Yeomans? If not, his books should (hopefully) be available at larger libraries. Try searching for
Keyline Plan (1954), Challenge of Landscape (195
and Water for Every Farm (196
. Good luck with it, and don't forget to let us know how you get on. Further concerning Keyline: Darren Doherty (see:
http://www.permaculture.biz/education/c ... tegoryID=2) runs a Keyline course, but has nothing scheduled at the moment. Darren is currently in the USA however, running a Carbon Farming course across California. Maybe you can catch up with him sometime in the near future?
Cheerio, Mark.