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<br />The location of the deepest velocity observation was determined by the <br />method of current-meter suspension and the presence of obstacles on the chan- <br />nel bottom. When it was necessary to suspend the current meter from a cable <br />with a sounding weight, the current meter could be placed no closer than <br />0.5 foot above the channel bottom. If large boulders were present in the <br />vertical, this minimum distance above the bottom was even less. For a stream <br />only 3 feet deep, the deepest possible reading is at 0.83 depth. In some <br />verticals a reading could not be obtained even at 0.80 depth. <br /> <br />The first set of velocity observations was made at Cottonwood Creek. <br />Velocities across the entire cross section were recorded using first one of <br />the two current meters, then the other. After the readings for the first <br />current meter were completed, and the second current meter was placed in the <br />water, the river stage had changed. To alleviate this problem in all subse- <br />quent observations, the current meters were alternated at each vertical. All <br />point velocities in a vertical were measured using one of the current meters. <br />Immediately afterwards, velocities were measured using the other current meter <br />in the same vertical. Time between readings by different current meters was <br />greatly reduced. No further problems with changing stage occurred. In all <br />subsequent measurements the depths of flow in each vertical were the same for <br />both current meters. <br /> <br />Placing each of the current meters in identical locations was difficult <br />during cableway and bridge measurements. High velocities and turbulent flow <br />conditions caused the current meters to move horizontally, even when heavy <br />sounding weights were used. There were no problems with vertical angles. The <br />cableways and bridges were all close to the water surface and depths were <br />usually shallow. When measurements were made while wading, exact placement of <br />the wading rod using alternate current meters was difficult at times because <br />of swift flow and shifting cobble and gravel on the channel bottom. <br /> <br />Water-Surface Measurement <br /> <br />Water-surface measurements were necessary to describe conditions in the <br />stream reach studied. Water-surface elevations were obtained by transit <br />~tarlia sllrvPy,..m~~~o._o....c...c_as.ions at pac:h sitp _Yla~~ac~ plpv::lti()n_~_ <br />readings usually were made at one point upstream of the measurement section, <br />at the measurement section, and at a point downstream of the measurement <br />section. Total horizontal distance of the slope measurement was normally <br />about two and a half times the stream width. Because of the often greatly <br />fluctuating water-surface and the soft bottom conditions sometimes found, it <br />was difficult to exactly locate the water surface. <br /> <br />Bed-Material-Size Measurement <br /> <br />Bed-material data was collected at each station. Because of the range of <br />bed-material size usually found, the Wolman method was used (Wolman, 1954; <br />Benson and Dalrymple, 1967). A measuring tape was stretched across the full <br />width of the stream, perpendicular to the stream axis. Particles were exam- <br />ined at intervals along the tape, usually at 3-foot intervals. Additional rows <br />of particles were examined 3 feet upstream and 3 feet downstream of the tape. <br /> <br />9 <br />