Capillary Zone from a Watertable

An artificial perched watertable was constructed by a watertable construction machine at about 0.5 m depth from the soil surface in an area where the annual precipitation occurs only in the summer season to retain summer runoff in this watertable. The zone of capillary diffusion from the underground watertable during dry season for seven months from September to March in which no rain occurs was determined in an indoor soil bin which had a transparent side and a float and needle system to maintain water at a constant level. The results showed that water proceeded quickly into a whole sand layer and then into a clay soil layer. When the capillarity diffused into three-dimensional clay soil layer, the maximum length of the capillarity was 4.1 m in horizontal direction and the minimum length was 0.95 m in vertical direction for the seven months. Hence, the distance required to operate the watertable construction machine was 11.2 m.