On steep land, land subject to slip or excessive erosion, or land in a climate where heavy and severe storm rain events are sporatic and infrequent Swales may cause problems of erosion and are best avoided. Similarly in very hard rocky areas, sometimes swales are simply not possible without extreme effort or maybe heavy machinery. In these situations, Contour Hedgerows can perform the essential task of helping more rainfall to pemnetrate the soil, but avoid the possible risks of swales. Contour Hedgerows will generally be slower to establish and be effective than the vegetation possible along a swale system, but sometimes the risk of swales is not warranted.
Start by carefully marking the contours of the site, by A-frame or water level. It depends largely on slope and soil type, but a hortizontal distance of 10 m. is reasonable. Shorter distances are possible if you want a more forrested result. Larger distances if agriculture or grazing is required.
Along this line, loosen the soil with a pick, for a width of 0.5m. If available, place a row of rocks along this line - three rocks high is great - but a lot of work!
Plant this line with whatever plant you have available, that will survive and plant as densely as possible. Any small bushes are good. Vetiver grass is very effective, but may need some irrigation to get established in very dry climates. Lemon grass is similar, but not for colder areas.
Often some care will be necessary in the early years. This may mean irrigation. It certainly will involve excluding grazing animals for many years. If mulch material is available, the lines could be mulched.
Carlos Caballero, (Tlaxcala, Mexico) has reforested a whole mountain (a small one) simply by roughening the surface of the soil and then laying down a layer of composted goat droppings (from his stables) - all of this on contour lines. The compost holding better moisture, so herbs start growing along this line, this traps more moisture and soil (being eroded from above), which helps hold more moisture. When the herbs die in the dry season they add to the organic layer, and again support more life in the next rains. Soon bushes are established. In some cases pine seedlings can be found established along these lines, amongst the herb layer within three years of placing the compost. In twentry years the whole montain was reforested, without ever planting a tree - Carlos replaced the lost organic materiasl from the site, and Nature did the rest!
In areas where animals are important for milk or work animals, it is better to cut and carry the forage to the animals, than allow them free access to the slope. If animals are permitted access, it must be very controlled and for short times only, with the animals being removed at the first sign ov damage to the plant truncks.
This form of working with the slope and shape of the landscape has been used in intensively used areas like Asia for thousands of years.