Spatial and Temporal Variation of the Particle-Size Characteristics of Fluvial Suspended Sediment

Although recent expansion of river monitoring programmes is generating a growing body of data on the magnitude of the suspended sediment yields of world rivers, much less is known about the particle-size characteristics of the sediment involved. Such information is, however, of increasing importance for a wide range of applications.Existing evidence indicates that there is considerable spatial variability in the particle-size characteristics of suspended sediment at the global scale and that rivers may also exhibit contrasting patterns of temporal variation. In response to a need for an improved understanding of the nature and controls of such variability at the local scale, this paper reports an investigation of the particle-size characteristics of suspended sediment transported by the River Exe and its tributaries in Devon, UK. Sediment samples were collected from eight measuring sites and the particle-size data obtained are used to emphasise the considerable contrasts in river behaviour that may exist at the local scale and to identify some of the important controlling factors.