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<br />Multiple-point vertical-velocity measurements were randomly taken <br /> <br />for several depths of flow at several of the sites to determine if the <br /> <br />vertical-velocity distribution of steep-gradient streams is logarithmic. <br /> <br />The velocity-profi les at two of the sites are shown in figure 9. All of <br /> <br />the vertical-velocity curves for different flow depths and at different <br /> <br />sites had this general shape. This shape probably is a result of rough- <br /> <br />ness caused by the larger bed particles protruding into the total depth <br /> <br />of flow. Near the channel bottom, the flow is retarded and the curve <br /> <br />shifts to the left of the logarithmic curve; near the surface, the flow <br /> <br />accelerates and the curve shifts to the right of the logarithmic curve. <br /> <br /> The differences between the integrated velocity, the velocity at the 0.6 <br />~B~~ depth (VO.6)' and the average of the velocities at the 0.2 and 0.8 <br /> 4. ~Theoretically, " <br />depths (VO.2+0.8) shown in table if the flow \ <br />(nur llIAl are on \ <br /> \ <br /> <br />these streams were deep enough, the vertical-velocity distribution would <br /> <br />approach a logarithmic curve. However, it is unlikely such depths of <br /> <br />flow would occur in steep-gradient streams. The discrepancy between the <br /> <br />measured vertical-velocity distributions and the logarithmic curve <br /> <br />becomes greater as the depth of flow decreases. The mean velocity was <br /> <br />underestimated at all sites at which vertical velocity;neasurements were <br />made, except Clear Creek at Lawson. <br /> <br />T~ ~ ~_~,fA ~ ~ ~ j---.J <br />~ ~..,;t~O.1th~. <br /> <br />-; <br /> <br />