BOARD00154 ‎(2)‎

• Board Meeting Date: 3/13/2007
• Description: ISF Section - Notice of 2008 Instream Flow Recommendations and Summary of ISF Workshop
• Board Meetings - Doc Type: Memo

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Table 3. Summary statistics of estimated mean daily discharge through Arapaho Creek based aerial
apportionment of the watershed above uas gage 7105000. For each month, the 50% exceedence is
highlighted. Yellow indicates summer months and blue indicates winter months.

Station: Arapahoe Creek at Monarch Lake Outlet 10: 09016500
Prameter: Daily Average Statistic: Daily Discharge
Year: 1944-1971 Latitude: 40 06'45"
State: CO Longitude: 10544'57"
County: Grand Elevation: 8310 It
Drainage Area: 17.4 mi2
Monthl Statistics
Jan Feb Mar A r Jun Jul Au Oct Nov Dec Annual
# days 837 762 837 810 810 837 837 837 810 837 9861
Avg Day 2.9 2.5 2.5 11.5 151.6 69.4 23.1 8.4 5.1 3.5 30.61
Max Day 6 6 9 141 430 365 102 60 24 24 430
Min Day 1.67 1.67 1.48 1.67 43.75 5.93 0.48 1.78 0.07 1.52 0.07
# months 27 25 27 26 26 27 27 27 27 27 25
Sdev Month 0.75 0.65 0.74 9.82 43.00 35.68 8.85 6.33 2.51 1.10
Skew Month 0.70 2.10 2.33 2.93 0.16 1.62 0.96 2.76 0.92 0.87
Min Month 1.80 1.73 1.67 3.15 29.89 67.42 28.53 9.88 2.63 1.61 1.65
Max Month 4.57 4.95 5.35 51.42 135.48250.94 190.73 46.79 34.24 11.41 6.32

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Percentiles.
1% 4.82 5.19 5.56 79.52 258.88 355.92 237.68 73.02 53.66 44.81 15.51 7.42 243.24
5% 4.45 3.52 3.78 50.45 197.56 275.61 162.55 47.68 27.27 22.32 10.75 5.19 152.02
10% 4.08 3.19 3.19 25.99 153.73239.16 131.63 39.08 16.69 14.46 8.90 4.82 99.37
20% 3.56 2.92 2.89 16.69 112.94 202.90 98.26 31.52 13.35 10.38 6.30 4.45 46.35
50% 5.19 61.92 141.09 55.62 19.28 6.30
80% 2.15 2.00 1.89 3.26 28.55 90.47 32.63 13.35 6.30 3.52 3.03 2.60 2.71
90% 2.04 1.85 1.78 2.67 17.80 72.30 27.07 10.38 4.82 2.97 2.52 2.30 2.22
95% 1.93 1.78 1.71 2.11 13.35 62.29 22.25 8.16 3.71 2.60 2.26 2.07 1.93
99% 1.76 1.67 1.56 1.79 8.66 51.24 17.19 2.36 2.80 2.00 0.24 1.59 1.67

. Percentiles estimate the value (discharge) in the record associated with a given percentile. They provide an estimate
of the percentage of days on which a given flow is exceeded. Percentiles were calculated using the PERCENTILE
function in MicroSoft Excel.

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