Sediment transport rates and sorting through a pool-riffle unit

Pool-riffle morphology is critical in sustaining fish and macroinvertebrate habitat, and a deeper understanding of maintenance mechanisms is helpful for restoration and rehabilitation objectives. Much debate has centred over various mechanisms of morphological maintenance, with most attention devoted to hydraulic reversal. Sediment trapping and tracing is used in this study to investigate sediment routing and sorting through a pool riffle sequence in an upland stream in the UK. The paper explores the role of sediment supply and grain routing upon morphological maintenance through an examination of bedload trap data (transport rate and grain size distribution) and tracer clasts. Tracer and bedload data are supportive of clast routing away from pools, and suggest that hydraulic reversal may not be required for pools to be maintained.