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<br />Barnes (1967) presented verified n-value data, color photographs, <br /> <br />and descriptive data for 50 stream channels. These verified data are <br /> <br />for ne~r-bankful I disc~arges but do not provide information on the <br /> <br />change of Manning's roughness coefficient with depth of flow. Limerinos <br /> <br />(1970) presented verified n-value data for 11 streams and a predictive <br /> <br />equation for Manning's n for various depths of flow as a function of <br /> <br />relative smoothness. The equation for n developed by Limerinos (1970) <br /> <br />is: <br /> <br />n = <br /> <br />(0.0926) R1/6 <br />R <br />1.16+2.0 d <br />84 <br /> <br />(4) <br /> <br />where d84 is the intermediate particle diameter, in feet, that equals or <br /> <br />exceeds that of 84 percent of the particle diameters determined by <br /> <br />methods described by Wolman (1954); and the other variables are as <br /> <br />described earlier. M~thods such as Limerinos' require particle-size <br /> <br />data. These data may not be availabl~ due to the hydraulic conditions <br /> <br />of the stream, such as large depths of flow, high flow velocities, and <br /> <br />economic or time constraints. <br /> <br />; <br /> <br />/0 <br />