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The sub-basins which make up Flume and Pyeatt gulches in the eastern portion <br />of the permit area, vary in basin slope from approximately 11 percent to over 24 <br />percent. Their drainage area ranges from about 150 acres to just under 1346 acres. <br />Geomorphic basin characteristics are summarized in Table 2.7-12b. <br />The drainages were classified to be first, second, third and fourth order <br />drainages, according to the Strahler method of stream ordering. Drainages were <br />defined using the contour crenulation method developed by Morisawa (1957) on a 1" _ <br />400' scale, 5 foot contour topographic map. <br />The number of each stream order was counted in the eight sub-basins to <br />determine the average number of lower order streams required to form a next higher <br />order stream. This number is called a bifurcation ratio (Schumm, 1977). In <br />- general, if a basin is elongated, a bifurcation ratio should be greater, than if a <br />basin is circular. This ie a result of a higher percentage of the area of a basin <br />being nearer to the main drainage in the axis of the basin. <br />The bifurcation ratio between first and second order streams ranged between <br />3.0 and 6.67 with an average ratio of 4.25. The elongated basins had the higher <br />ratios. The bifurcation ratios between eecond order and third order streams do not <br />relate to basi^ shape in the Trapper permit area. The values range from 2.0 to 4.67 <br />with an average of 3.46. These ^umbers imply that on average, there are 4.25 first <br />order streams for every second order stream and 3.46 second order streams for every <br />third order stream. <br />Drainage density defined as total stream length smiles) divided by basin area <br /> <br />2-454a REVISED ~ 13 '87 <br />