Research is currently underway to investigate the physical mechanisms which cause loss of coherence in scattered light. It has been shown that, for Brownian motion of particles in a scattering medium, the coherence of incident light decreases rapidly with path length and diffusion coefficient. Experiments confirm that laser light scattered by a water column loses coherence as a function of path length and water turbidity. An experiment has been performed which measures coherence length versus temperature, optical path length, and water quality. The results are reported here. Based on these results and research into the causes of spectral broadening, experiments are proposed to measure each type of broadening mechanism with a much higher degree of accuracy.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.