Homepage 2019 » Forums » Permaculture Design » Need help designing swales.

This topic contains 4 replies, has 4 voices, and was last updated by  jluvalle 2 years, 10 months ago.

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    What do you do if you don’t have good contour lines? Where i want swales my property slopes North – South towards the road AND East – West toward driveway. My thoughts are to dig a level trench E-W to form the swale. Soil (sandy clay) would need to be moved end to end to create a level berm. Unfortunately the ideal place to put the overflow would be on the uphill end of the berm. I have about 4-5 foot elevation change over about 800 ft (3 acres). Average rainfall of 40 inches (1 meter) so a lot of rain water is leading the property. Summers are often mostly rain free if you can imagine that.

    Most of the earthworks will be done by hand creating 4-6 ft (1 – 1.5 meter) wide hugal swales. I will pobably need 2 small ponds in final phase. I live in zone 8-9 semi tropical area, high heat and humidity.

    Can anyone help?



    A swale needs to be level following the contour. There shouldn’t be an uphill end. If you try to do anything that is not level you will just end up fighting against water and erosion. Consider moving the swales higher or lower on the slope. In some areas I have staggered swales. As the water overflows from one swale to the next it slowly gets moved to where I want to store it. Or are you concerned with the actual direction of the contour? As in you wanted them to run east to west but they run north to south?



    Swales. How big? How many? How far apart?
    Its a small urban lot, near the creek, in Austin. Its either drought or flood down here. When it rains (hard) all the water from the neighborhood flows downhill, through my yard, towards the creek.
    I’ll eventually add gardens, food forest, pond, greywater, etc. For now, I figured start with the big earthworks part first. Is there a guideline for sizing out swales and berms?



    You might consider using an A frame level, and using fish scale swales (small crescent ones that cover the slope, so overflow goes to the one below and so forth. That avoids the problem of having a very large swale, and you can do it more incrementally. If you really want the long swale use landscape flags to identify the ends of the A frame level, then measure the next section and mark that, then just dig the swale between the flags.
    If you lay out 4-5 flags you can identify the count our pretty well, and you avoid winding up with a drastically non level swale.

    Regards, John



    Darn spell check. That is “identify the contour” not “identify the count our”

    sorry bout that,


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