Particle-size measurements by Coulter Counter of very small deposits and low suspended sediment concentrations in streams

Abstract The Coulter Counter method of particle-size analysis, based on particle volume, is outlined. The method and associated procedures, previously used for soils, have particular use in particle-size analysis of fine sand and silt in quantities below the sensitivity of settling velocity and sieve methods. Schedules are presented here for pretreatment of samples and particle-size analysis by Coulter Counter. Application of the method is illustrated for particle-size analysis of individual sedimentary laminae, small features in soils, and suspended sediment in streams. Concentrations of suspended sediment recently reported for streams in eastern Australia are much lower than those generally published for the United States. The conventional methods used for particle-size analysis of the latter do not seem applicable where suspended sediment concentrations are low; the Coulter Counter method is an appropriate alternative.