The aim of this study was to identify a method for determining the number of tracer particles required to define the mean longshore transport distance of indigenous littoral shingle with a particular level of precision. A method is presented which can be applied to existing tracer data to determine both the precision of the measurements collected and the number of tracers required to achieve a particular level of precision. The method, which utilises well established statistical relationships, is demonstrated by applying it to archive tracer data. The study demonstrates the sensitivity of the number of tracers to the variance of the transport distances of indigenous particles at the site and the precision with which the investigator wishes to define the mean. It is anticipated that application of the method by other practitioners, in the future, will allow a dataset to develop which can be used alongside the method presented here to allow the number of tracers required for a study to be estimated prior to entering the field. Results are presented to initiate the development of this dataset and a “look-up chart” derived using the method is given to aid its application.

The accurate estimation of coarse sediment transport rate remains one of the goals of geomorphological and engineering studies of river channels. This paper describes an experiment designed to assess the accuracy of the Spatial Integration Method (SIM) of determining sediment transport rate or yield, using passive tracers. Tracer dispersion results are presented from five events of different magnitude. The study concludes that the SIM is capable of producing estimates of sediment transport rate that correspond with trapped values. Sources of error are quantified and guidance is given on the appropriate methods for deploying passive tracers for the estimation of coarse sediment transport rates.