A new model for the vertical distribution of suspended sediment, which has the form of an error or Gaussian distribution function, agrees with the classical model in the central flow region and has a major advantage in that its integral over the flow depth converges to a consistent estimate of the measured average sediment concentration. The average concentrations predicted by the model compare favorably with concentrations derived from sediment load measurements in both the laboratory and the field. The theoretical diffusion coefficient distributions associated with classical and error function models are also similar.