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<br />0':. . <br />Co' <br />'l::'" <br /> <br />c <br /> <br />. , <br /> <br />Diurnal Flow Pattern - Examination of daily streamflow fluctuation at West Beaver Creek gage <br />indicates that the general pattern of flow (represented by the ratio of the hourly flow to the mean <br />daily flow) as shown in Figure 2 is very similar from day to day and year to year. The minimum <br />flow occurs near 12 noon and the maximum somewhere between 7:00 and 10:00 pm. The <br />hourly flow fluctuates approximately 20 percent above and below the mean daily flow. <br /> <br />Further anaiysis reveals that the pattern changes slightly as the melt season progress. The <br />magnitude of the fluctuation decreases as does time between the minimum and maximum flow. <br />Figure 5 presents the diurnal flow patterns for early and late in the melt season. The early <br />pattern has minimum and maximum flows that vary approximately 20 percent above and below <br />mean daily flow. The minimum flow occurs at approximately 13.0 hours (1:00 pm) and the <br />maximum at approximately 22.0 hours (10:00 pm). The late pattern has daily extreme flows <br />that vary approximately 15 percent above and below the mean daily flow. The minimum flow <br />occurs at approximately 12.5 hours (12:30 pm) and the maximum occurs at approximately 19.5 <br />hours (7:30 pm). The time of the minimum occurs at approximately the same time throughout <br />the melt season. The time of maximum shifts to earlier times as the melt season progresses. <br />Table 7 presents the mean and standard deviations for extreme points of these two patterns. <br /> <br />Predictabilitv - The standard deviations of the extreme points presented in Table 7 can be used <br />as a measure of the reliability of hourly flow estimation in the eariy and late segments of the <br />melt season. The standard deviations are larger for the early segment of the melt than those for <br />the late segment. This indicates that the curve representing the pattern in the early segment of <br />the melt season is a somewhat less reliable predictor of hourly streamflow than the curve <br />representing the pattern tor the late segment. The variability of the early season minimums and <br />maximums are twice those of the late season flows. On anyone day, the minimum or <br />maximum flQw early in the melt is more likely to differ from the mean value than late in the melt. <br /> <br />:-1 <br /> <br />:"1 <br /> <br />7 <br />