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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I' <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />RM 105.0. The SS site was located at the upper portion of the representative reach. At <br />Sevens the RR station was 4.0 miles in length and was from RM 64.0 to 60,0. The SS <br />site was at the lower section of this reach. The electrofishing raft moved downstream <br />while in operation. The same mark was used for all fish outside the SS site but was <br />changed between days, Duffy RR was electrofished on September IS, 16,22,24 and <br />30. Sevens was sampled on September 17, 18, 23, 29, and October I. <br /> <br />INVERTEBRATE SAMPLES <br /> <br />Aquatic invertebrates were collected at the two study sites using a surber <br />sampler. Six samples were taken in July, August, September and October along an <br />established transect line. Depth, velocity and the distance from the reference pin were <br />measured for each sample. Sample densities were tested for difference based on depths <br />with depths of 0.1 to 0.2 ft considered shallow, 0.4 to 0.6 ft were medium, and 0.8 to 1.0 <br />ft were deep. Most specimens were identified to species and a Shannon Weaver ' <br />Diversity index was calculated for each sample. Miller Ecological Inc. made <br />identification. <br /> <br />At Duffy, the collections were made on July 23, August 20, September 3, and <br />October 8. Samples at Cross Mountain were on the same date except during July when <br />the sample was taken on July 30. Flows on those dates are given in Figure 2, <br /> <br />HABITAT MAPPING <br /> <br />During July and August of 1998, a Pentax PTSm total station was used to obtain <br />XYZ data points (<3cm total error) for two reaches on the Yampa River (Figure 3). The <br />first reach is located approximately 15 miles upstream of Juniper Hot Springs near the <br />Duffy Tunnel diversion. This site is approximately 1.3 Ian long and is represented by <br />3777 data points. The second site is located adjacent to the Sevens Ranch <br />approximately five miles upstream of Cross Mountain Canyon. This site is <br />approximately 1.2 Ian long and is represented by 1900 data points. Both sites have an <br />average width of about 100 meters and have slopes of.08% and .03% respectively. <br /> <br />A Trimble GeoExplorer GPS was used to tie the XYZ data points into a <br />meaningful geospatial reference system. At each of the two sites, at least two ground <br />control points (GCP's) were determined using a 15 minute averaging routine and then <br />were differentially corrected to give centimeter accuracy for each GCP. At each site, <br />one GCP was selected to be the reference position and other GCP's were used for <br />determining aiimuth and as a rough check on total station coordinates. <br /> <br />Data points were gathered during the low flow periods by walking, wading, or <br />floating the channel with a collapsible rod and prism. Instead of shooting bed profiles <br />along transect lines, data points were taken at intervals dependent on the topography or <br />breaks in slope. Where channel topography was highly variable, more points were <br />captured compared to areas with relatively flat surfaces. <br /> <br />A relative measure of channel substrate was recorded for each XYZ data point. <br />Substrate was determined visually on dry land and on shallow riffles, by feel where <br />water was shallow enough to wade yet too deep to visually estimate, and by tapping with <br /> <br />5 <br />