“A swale is a ditch dug on contour. This means that water is not draining in one direction — instead it spreads evenly across the slope and sinks into the soil. Traditionally, the earth that is dug out is placed on the downhill side and planted out with a mixture of perennial and annual crops (but always perennial to ensure that the earth is stabilized with good long-term root structure).”
Tips for using swales as pathways: Use low cost agricultural by-products such as rice hulls, saw dust and wood chips in the swales so the paths are not too muddy. Plan ahead so the pathways are wide enough for whatever size wheelbarrow or garden cart you’re going to use. You may need to plant vetiver grass, etc. along the sides of the raised beds to prevent erosion of soil into the swales.
More details and photos at Permaculture News.org