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<br />o <br />r:l and across the stream made possible recurrent measurenh3nts at the same <br />N <br />W locations.. The basic :!T~ormation obtained from these ;:;tudies is <br />to <br />eo illustrated in Plate VI.. <br /> <br />530 An analysis of the data. obtained in this rnal1'.1er brought to light <br /> <br />valuable information regarding the effect of wp.ter volumes and velocities <br /> <br />upon aquatic h8.bitat types.. Because of inherent differences in the amount <br /> <br />of habitat historically provided by the reach above Willow Creek as compared <br /> <br />with the reach below Willow creek~ and the water requirements necessary to <br /> <br />preserve that habitat9 it was found that the data for each of these sections <br /> <br />(;f the river had to be analyzed sep~ra.tely.. Paragraphs 54 through 56 refer <br /> <br />to the reach from Granby Dam to the mouth of Willow Creek, while pa.ragraph <br /> <br />57 refers to that part of the river between the mouths of Willow Creek and <br /> <br />Fraser River.. <br /> <br />54.. Abov.e 800 cubic feet per second9 it was observed that all pool <br /> <br />and riffle areas disappeared and the entire habitat l'ITaS deep-fast water. <br /> <br />At this stage9 the stream. was rurming bank~full or over, and aquatic habitat <br /> <br />occupied 100 percent of the stream bed.. Below 800 cubic feet per second, <br /> <br />deep~fast water occupied progressively less area.. In its place pools and <br /> <br />riffles developed.. The maximum percentage of stream bed in pool and riffle <br /> <br />area was reached at between 130 and 140 cubic feet per second.. Below 130 <br /> <br />cubic feet per second the percentage dropped swiftly. These findings are <br /> <br />illustrated in Figure 1.. Conditions as shown by the graph are projected <br /> <br />to 800 cubic feet per second as the point at Which the percentage of pools <br /> <br />and riffles reaches zero and the stream bed becomes 100 percent aquatic <br /> <br />habitat.. <br /> <br />550 Pools and riffie s are of extreme importance. A sepa.rate analysis <br /> <br />of the data concerning each of these types showed that the maximum. number of <br /> <br />-20- <br /> <br />,.; <br />