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Table 4. Current velocity in meters /sec, measured November 15 and 16, 1994, and observed <br />substrate size <br />distribution at each sample location. <br />SiM Mean <br />Velocity <br />Thalweg Velociy <br />Substrate Size Distribution <br />U5 <br />0.41 <br />0.72 <br />100 % boulders <br />U4 <br />U3 <br />0.48 <br />0.73 <br />50% boulders, 45% cobble, 5% gravel <br />U2 <br />0.51 <br />0.42 <br />0.61 <br />70% boulders, 25% cobble, 5% gravel <br />U 1 <br />Q,U <br />0.65 <br />42% boulders, 52% cobble, 2% gravel, 4% silt <br />QJA <br />58% boulders, 40% cobble, 2% gravel <br />Average: <br />0.43 <br />0.65 <br />DI <br />0.67 <br />0.77 <br />62% boulders, 37% cobble, 1% gravel <br />D2 <br />0.32 <br />0.52 <br />60% boulders, 33% cobble, 7% silt <br />D3 <br />0.49 <br />0.93 <br />67% boulders, 30% cobble, 3% gravel <br />D4 <br />0.51 <br />1.02 <br />93% boulders, 7% cobble <br />D5 <br />U-6 <br />Q <br />72% boulders, 26% cobble, 2% gravel <br />Average: <br />0.47 <br />0.75 <br />mainly of narrowleaf cottonwood and box elder trees, with varying amounts of shrub <br />understory, including gambel oak, chokecherry, serviceberry, snowberry, and red osier <br />dogwood. Trees were smaller and there were more shrubs in immature woodland than in <br />mature woodland. Unvegetated ground consisted mostly of boulder riprap placed by the <br />Colorado Department of Transportation during highway reconstruction, as well as areas <br />adjacent to the river channel covered by cobbles. Access to the river is generally restricted on <br />the south side. We found no large areas of recent disturbance, and other than areas of riprap, <br />or cobble areas near the river channel, most of the riparian land is well vegetated adjacent to <br />the river. Table 5 shows the percentage of each cover class bordering the channel. There was a <br />small percentage of the stream bank where the ground was eroded to form vertical banks (also <br />included in Table 5), however, most of the stream banks appeared to be stable. There were no <br />areas of overhanging banks or overhanging vegetation. <br />Water Quality: <br />The discharge plume was detectable by taking measurements of conductivity while wading <br />back and forth across the channel. The plume was only a meter or so wide at D1 and gradually <br />widened to encompass the northern third of the channel by the time it reached D3. Field <br />measurements of electrical conductivity taken at the sampling stations in March and October <br />reflected the presence of the plume, and were highest immediately downstream of the <br />15 <br />