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<br />. <br />found to be usable (Appendix 2, Table 8), Percent surface area of the river with usable habitats <br />was lowest (36%) at 60 cfs, even though usable area decreased with flow. At flows over 150 cfs <br />deep runs become the most common habitat type in the sequence. <br /> <br />Combined clusters in Strata 6 <br /> <br />Figure 14 and Appendix 2, Table 9 show habitat composition when all 20 cross sections in <br />Strata 6 are combined. Total river reach represented by the 20 cross sections (5,622 ft) is 3.6 % of <br />Strata 6 (29.9 miles). <br /> <br />Shallow pools (unusable habitat) are the most common habitats available at flows between one and <br />100 cfs. Between 150 and 250 cfs shallow runs are the most common habitats. <br /> <br />Figure 15, gross habi tat versus flow, shows a rapid increase in wetted surface area between one <br />and 100 cfs, but between 100 and 400 cfs surface area increases linearly. Usable surface area <br />increases in a fairly linear relationship with flow between 1 and 250 cfs. The amount of usable area <br />at 200 cfs is only double that of what is projected at I cfs. <br /> <br />With only one cfs of flow, the wetted surface area of the river models to be 97,263 square feet <br />per 1,000 ft of stream (Appendix 2, Tables 6-9). This means the average stream width of is 97.3 <br />feet at just one cfs. The river maintains width at very low flows because of its flat gradient and the <br />low width/depth ratio found at Clusters 73.3 and 77.8. <br /> <br />A width/discharge relationship was determined by averaging the widths of each cross section in <br />a sequence for each of thc simulated flows. (Mean cross-sectional width is not the same as the <br />mean stream width as dctcrmined by Appendix 2, Tables 6-9). The width/discharge relationship <br />was highly variable for cross sections within a cluster and between clusters (Figure 16). High <br />gradient habitats (rimes) had narrower widths at low flows than low gradient habitats with low <br />width/depth ratios <br /> <br />Cluster 73.3 had the lowest average cross sectional width at leI's (54 ft) and Cluster 62,8 had the <br />widest average cross section width at 400 cfs at 242 ft. Between one and 100 cfs, stream width <br />increases rapidly with flow, but at t10ws between 150 and 400 cfs the relationship is fairly linear. <br />Mean channel width, grass line to grass line (all cross sections combined), was found to avcragc <br />about 280 n. and the mean cross section width of this strata at 400 cfs was 229 ft or about 82% of <br />the bankfull width. <br /> <br />33 <br />