The settling speeds of flocs of fine-grained, natural sediments approximately 10--200 μm in diameter have been measured in both fresh water and seawater. These flocs were formed at fluid shears of 100, 200, and 400 s-1 and at sediment concentrations of 10, 100, and 400 mg/L, values typical of conditions in the near-shore areas of lakes and oceans, especially during storm conditions. It is demonstrated that settling speed of a floc is a strong function of fluid shear and sediment concentration as well as of the diameter of the floc, but it is a weak function of salinity. For the same diameter and salinity, flocs, produced at the lower fluid shears and sediment concentrations have lower settling speeds than do flocs produced at higher fluid shears and sediment concentrations. If the conditions of fluid shear and sediment concentration under which the flocs were produced are unknown or ignored, it is shown that the settling speed of a floc is a weak function of diameter and salinity. ¿American Geophyscial Union 1990