Patterns of gullying in Zimbabwe

Abstract

In Zimbabwe four contrasting gully locations and associated gully patterns are present, reflecting spatial variations in precipitation, bedrock, soil type and landuse. Deep dendritic gullies, associated with landslip activity and subsurface piping, characterise the wet Eastern Highlands and areas with sodic soils. Shallow discontinuous gully systems characterise bornhardt terrain in the Communal Lands. Dambo gullies tend to form a continuation of the fluvial system. The pattern and temporal variation of gullies was studied in three areas of Communal Land (Mhondoro-Ngesi, Mangewende, Mutema) with particular reference to the influence of average slope and landuse on gully development. In areas of sodic soils the gullies appear to be largely the product of natural processes and their development has only partly been influenced by landuse changes. In contrast the shallow gullies developed on granitic/gneissic terrain tend to occur on cultivated or recently cultivated land. The case studies indicate that a full assessment of gully development can only be achieved if a temporal perspective is also considered.