Bed grain size plotted as a function of distance and flow depth

Bed grain size plotted as a function of distance downriver and flow depth. Each of the 8 plots represents a different survey. Each dot shows the location of an individual grain size sample; color of the dot represents mean grain size of that sample. Because sampling density is too great to plot without most points being concealed by other points, the location of each point on the plot is shifted by a small random displacement. The background color is a smoothed surface fit to the data (color-coded using same color scale as used for individual points).