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9. <br />RESULTS AND DISCUSSION <br />Habitat Observations <br />Yampa River Trend Zone <br />The Yampa River between Maybell and Sunbeam, Colorado, is a mature, <br />meandering river flowing entirely on an alluv4--1 bed of cobble and smaller <br />substrate (Table 1). The reach is generally characterized by run-crossing <br />bar sequences, sparsely vegetated alluvial islands and exposed bars at low <br />flows. Few deep-water areas occur in the reach, and gradient is essentially <br />constant at less than 0.001. The entire reach to station F is bordered on at <br />least one side by irrigated agricultural areas. <br />Major positive habitat attributes: <br />1. Deep-pool area below the bridge north of Maybell. <br />2. Low-flow backwater areas at stations A, B and C. <br />Major areas of concern: <br />1. Shallow, low gradient nature of reach and deposition of <br />sediment during low flow years. <br />2. Intense grazing during winter and spring and resultant <br />bank destabilization, especially between stations C and F. <br />3. Instream activities near the bridge at station A. <br />4. Critically shallow crossings which might impede migrations <br />or movement during low-flow periods. <br />Water quality impacts: <br />1. Temperature effects of summer low-flows because of extreme <br />shallowness. <br />2. Salinity effects of irrigation return flows. <br />Water quantity impacts: <br />1. Proposed dams upstream. <br />2. Irrigation diversions <br />Land-use impacts: <br />1. Water quality associated impacts from agriculture and grazing.