Terracing or Keylined Swales?

Hello all.

I am in the planning stage for a project and could do with some guidance.

I am looking taking over some land and then going the whole Sepp Holtzer on it. It's a mess at the moment, but very repairable given time and effort.

The land is in the north of the UK - wet, sandy soil.

I know that swales are the cool thing at the moment, but Holtzer goes all all for full terrances. If I am going to be getting in heavy plant anyway for the swales, then going the full terrance route isn't vastly more effort. I.e Key-lined terraces.

My thinking is that I would make a series of terrances around 60 foot wide, with a berm at the edge of each terrance. Heavy planting with a mixture of shallow and deep rooted on the berms and job done.

I know this would move more sub-soil to the surface, but I am planning on a restoritive grazing approach, and so this would really just add a couple of years to the process.

Apart from the initial investment in time and labour, are there any other benefits of a swale/berm approach over a full terrance approach, assuming I follow all the resat of the keyline principles?


Thanks

Steve

Hi Steve,

We chose a combined approach, both terraces and swales. The main reason is management of water flows in times of too heavy rains to prevent the terraces from getting too soaked. Our terraces lean into the slope and drain of into the swales, which transport excess water to our ponds. The ponds overflow into the next subsystem until they reach the end of the property (sink) and excess water can leave through the existing gullies / seasonal streams.

Wow - I like that very much indeed.

So - how did you do this? You put in a very mild slope - say 1 degree? - so that normal rain sinks in, but deluges wash away?


How much of an impact did you find in terms of the large engineering leading to sub-soil being at the surface? Were you able to cope with it?

Steve

Hi Steve,

We work small scale,digging by hand. Yes, the terraces lean only slightly back, I believe 2 degrees is considered optimal. Excess water drains from the back through a stone filled channel that cuts through the terrace.

I think you want to work with machinery to get it done. In that case you could have them scrape the topsoil off first and put it back after the terraces have been shaped.

Main point I believe is that choosing earthworks should not be an either / or choice, but should combine different solutions depending on the site and on what to grow. We use the terracing for our garden and crop systems, but if we don't manage the water flow in the wet periods our terraces will wash out. For our tree systems we just use swales.