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<br />100-year flood discharges were plotted on logarithmic-normal paper and
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<br />
<br />a discharge-probability curve was drawn by using a standard deviation
<br />
<br />
<br />that was prorated from'the computed standard deviations of 0.232 at the
<br />
<br />
<br />Fort Collins stream gage and 0.457 at the Greeley stream gage. The
<br />
<br />
<br />proration was linear, based on channel distance from the respective
<br />
<br />gaging stations. The resulting discharge-probability curves were used
<br />
<br />
<br />to determine the 10-, 50-, and 500-year discharges at each location.
<br />
<br />
<br />Discharges for the Cache la Poudre River from the bluffline to the
<br />
<br />
<br />mouth are siven in table 7. Coalbank Creek is a poorly defined
<br />
<br />
<br />watercourse entering the Cache la Poudre River from the north about 3
<br />
<br />
<br />mdles upstream from Eaton Draw.
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<br />.
<br />
<br /> Table 7
<br /> Cache La Poudre River
<br /> Plains Area
<br /> Discharge-Probability Relationships
<br /> Drainage Flood
<br />Station Area 10-Year 50-Year 100-year 500-year
<br /> (sq. m!.) (c.i.s.) (c.i.s.) (c.f.s.) (c.f.s.)
<br /> B1uffline 1,055 7,000 13,500 17,400 31,000
<br />u/s from Dry Creek 1,102 8,400 13,700 16,200 23,800
<br />D/s from D"y Creek 1,195 10,100 16,600 19,700 28,200
<br />u/s from Boxelder Creek 1,245 8,000 13 ,700 16,600 24,000
<br />D/s from Boxe1der Creek 1,537 17 , 700 23,700 28,500 42,000
<br />u/s from Consolidated
<br />Law Ditch 1,662 2,650 5,200 6,600 10,700
<br />D/s from Consolidsted
<br />Law Ditch 1,707 4,400 8,700 11 ,000 17,900
<br />u/s from Coal bank Creek 1,747 2,250 4,800 6,300 10,900
<br />D/s from Coa1bank Creek 1,810 3,400 7,300 9,600 16,500
<br />u/s from Eaton Draw 1,825 2,680 6,000 8,100 14,600
<br />D/s from Eaton Draw 1,875 3,550 8,000 10,700 19,000
<br /> Mouth 1,890 3,100 7,100 9,400 16,800
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<br /> 22
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