A casual glance might lead you to believe that farmers carve them into hillsides, using the dug-up rock to build the retaining walls and the excavated earth to level the terraces. Well ...

See Hardscaping 101: Retaining Walls. Above: Granite stairs bordered by ferns are cut into the hillside. Photograph courtesy ...

The builders move a large amount of gravel from the slope above to fill in the area behind the retaining wall. Whenever possible ... channels dug into the hillside, a wooden sluice, or some ...