This article here by Patrick Whitefield summed up what I was always thinking:
http://patrickwhitefield.co.uk/one-permacultures-holy-cows-death-swale/
Much of the benefits of swales seem to be to do with water capture, since we have a lot of rain in the U.K and Ireland and its pretty flat overall I have been trying to determine the need for them here in relation to uk permaculture design. Obviously like the artcile I am not saying they are useless and no site here would ever need them its a case of finding their right application. Swales do provide a raised bank of drier land and catch debris and other runoff and as mentioned in the article could possibly prevent flood waters coming from higher land.
However if swales are not as potentially beneficial for our climate as elsewhere what are the other options for earthworks here? This lead me to think of pre industrial earthworks still around the U.K. Around here there are still some untouched ridge and farrow fields. However as the ridge and farrow run in the direction of the hill slope and now have only sheep grazing on them the benefit of the microclimates and extra surface area they produce would be less beneficial to thier current application.
http://en.wikipedia.org/wiki/Ridge_and_furrow
However I did find some more earthworks:
http://en.wikipedia.org/wiki/Lynchet
Obviously this is very close to a terrace system. Is there a modern terrace example in the U.K?
http://en.wikipedia.org/wiki/Water-meadow
Most people know about these because we foolishly build houses on them.
Can anyone think of any other U.K and Irish farming methods from the past that could be applicable today?