Development of piping erosion conditions in the Benson area, Arizona, U.S.A.

Abstract

Summary Piping is a subsurface form of erosion which involves the removal of subsurface soils in pipe-like erosional channels to a free or escape exit. Although it develops in different types of soils and under a wide range of physico-chemical conditions, piping materials are commonly highly erodible. The present study in the Benson area, Arizona shows that piping commonly develops in alluvial deposits in the vicinity of arroyo-cuts and deeply incised gullies actively trenching in the flood plain deposits. It shows also that soils susceptible to piping usually comprise silts and silty sands with a low clay content, and that they are generally of low dry density, high void ratio, and have collapsing properties. It was found that overgrazing the area of study in the past and misuse of the land, combined with the climatic conditions of long dry summers with intermittent short rain storms, have contributed to the initiation and development of piping erosion. Gully erosion and badland topography are quite extensive in the area of study due mainly to the collapse of the pipes at an advanced stage of their development.