Stream velocity profiles and longitudinal dispersion

Cross-sectional velocity distribution measurements from the Sacramento Delta, Northern California, have been analyzed in order to extract values of the parameters that characterize longitudinal dispersion. These parameters are the velocity deviation intensity ratio and a dimensionless constant derived from the velocity profile by triple integration. Fischer estimated these parameters by combining laboratory measurements, theoretical derivations for ideal cases, and data from real streams. The results presented in this paper show that the parameter values used by Fischer may lead to a significant overprediction of dispersion in the delta channels. With a view to future numerical modeling, a quartic profile function was defined and shown to provide a reasonable model of measured transverse velocity profiles.