Factors controlling the distribution of piping in Britain: a reconnaissance

The distribution of piping in Britain has been studied from a survey of 74 piped basins, and a number of in-depth studies at the individual basin scale. The survey suggests that nearly 30% of Britain is susceptible to piping erosion. This is the area covered by soils with histic and vertic properties or with impermeable subsoil horizons, lying in upland regions with high annual water balance and steep slopes. intrabasin scale, the intensity of piping shows a broad correspondence with the as drainage index, although there is no fixed relationship and some significant deviations are found. Inhomogeneities in soil properties and differential exposure to cracking may be the main cause. Landuse and vegetation cover may also affect distributions. However, the clearest intrabasin links between pipe distribution and vegetation patterns are found in upland moorland, where the pipes are the cause rather than the product of patterns in both soils and vegetation.