Piping in loess-like and loess-derived soils: case study of Halenkovice site, Czech Republic

Abstract

The soil piping that occurs on luvisols in the vicinity of the village of Halenkovice was studied for 5 years. These piping phenomena can only be found where arable land meets the forest or a belt of shrubbery. If there is a scarp in the locality, which usually changes from 6° in the field to approximately 30° in the forest, soil pipes are more likely to occur. Before the scarp, the slope flattens out and it is almost horizontal. This factor makes it possible for the overland flow to seep into the slope. This seepage results in soil piping, which is formed in loess loam and colluvial deposits. There are about 15 sites in the vicinity of the village of Halenkovice, where soil piping occurs. In one of them, Halenkovice 1 (an area of 900 m2) we closely studied 47 partial cavities. Their internal volume is 3.8 m3. The volume of the sink holes is 23 m3. There are two types of soil pipes – vertical, which on average tend to be shorter (40 cm) and lead the water under the surface, and soil pipes parallel with the slope, which are on average 81 cm long. Water flows through the pipes during a thaw or precipitation, which often takes away the top soil. The intensity of this process depends on the intensity of precipitation, which occurs outside the growing season, when there are no crops in the fields.