Vertical profiles of velocity and suspended sediment in streams near Mount St. Helens, Washington

Vertical profiles of high suspended-sediment concentrations and high velocities in stream near Mount St. Helens were measured between January 1981 and May 1986 at seven gaging stations. Data-collection methods are described and the numerical data are tabulated and plotted. Values for the exponent of the sediment-distribution equation were computed for several sand-size ranges using the least squares method. Logarithms of concentration of a size class at various depths (y) are plotted versus the logarithms of D-y/y (D = flow depth). The ratio of point velocity to mean velocity is plotted versus normalized depth. Selected plots of the logarithms of concentration of fine sand (0.125 to 0.250 millimeters) versus normalized depth (height above streambed/depth) show the vertical distribution of a predominant sediment-size range. (USGS)