Bed stresses in the bottom boundary layer of the York River estuary, Va., were estimated from 3D near-bottom velocities measured by Acoustic Doppler Velocimeters (ADVs) and also by a profiling array of electromagnetic current meters. By assuming the measurements were made in a constant stress layer, four methods of stress estimation were evaluated using ADVs: (1) direct covariance (COV) measurement; (2) turbulent kinetic energy; (3) inertial dissipation utilizing the Kolmogorov spectrum; and (4) log profile. The four methods yielded similar estimates of frictional velocity U* based on ADV output from both 14 and 44 cm above bed. All eight estimates of average U* were consistent with the overall mean of 1.10 cm/s to within the 95% confidence interval for individual burst estimates. The COV method worked slightly better nearer the bed, possibly because of the sensitivity of COV to the upper limit of the constant stress layer. The inertial dissipation method performed marginally well at 14 cm above bed, like...