Controls of soil pipe frequency in upland blanket peat

Soil pipes were surveyed in 160 British blanket peat catchments using consistent application of ground penetrating radar. Soil pipes were found in all catchments. The mean frequency of piping was 69 per kilometer of surveyed transect. Land management (moorland gripping) appears to exert the most important control on hillslope pipe frequency in blanket peats. Management practice in peatlands may therefore induce more rapid subsurface erosion, carbon loss and landform denudation via enhanced preferential flow. Topographic position is also important, with topslopes having greater pipe frequencies than footslopes, followed by midslopes with lowest frequencies. Slope gradient, however, is not a significant factor in controlling blanket peat pipe frequency. I propose that peat structural properties inherited from the way a blanket peat develops on a hillslope strongly control pipe network development. This is manifested in the way slope position appears to control pipe frequency. Aspect appears not to influence frequency in blanket peats except that it does play a weak role in catchments with annual precipitation less than 1500 mm. Here southwesterly-facing slopes tend to have more frequent piping.