Observations of sound wave backscattering by turbulent water (free of particulates) in a water flume using a high resolution, 1.5 mm wavelength, Doppler sonar, are presented and discussed. The results show that the backscattering produced by water turbulence yields well defined Doppler spectra containing velocity variance information relevant to the study of water turbulence characteristics. Near the flume bed, the observed Doppler velocity spectrum width is greater than that expected from the turbulent velocity spectrum and other known sources of spectral broadening. The excess Doppler spectrum width may be explained assuming that the temperature structures acting as sonar targets tracing the velocity eddies, have a transient nature. ¿ American Geophysical Union 1990