ISFAPP01512

• Case Number: 03CW0269
• Stream Name: Red Dirt Creek
• Watershed: Rock Creek
• Water Division: 5
• Water District: 53
• County: Routt
• Instream Flow App - Doc Type: Supplemental Data

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Hydrologic Data

After receiving the cooperating agency's biologic recommendation, the CWCB staff conducted
an evaluation of the stream hydrology to determine if water was physically available for an
instream flow appropriation. The hydro graph below was derived from data collected by the
USGS stream gage for Egeria Creek near Toponas, CO (ill #09060700), which has a drainage
area of 28.2 square miles (See Gage Sw:nmary in Appendix C). The total drainage area of the
Red Dirt Creek Drainage upstream of Rock Creek is approximately 11.6 square miles. The
period of record for this gage was 1965 - 1973, the period of record used by staff in their
analysis was 1965 - 1973, or 8 years of record. Table 2 below displays the estimated flow of
Red Dirt Creek upstream of Rock Creek, in terms of a percentage of exceedence.

Table 2: Red Dirt Creek estimated flow upstream of Rock Creek.
Exceedences Janua Februa March A ril Me
1% 2.67 3,02 6.17 30.03 lI8.a2
5% 2.52 2.47 6.11 20.57 !;3A8
10% 2.39 2.34 5.43 17.28 45.25
20% 2.14 2.22 3.78 11.11 :~8.79
50% 1.85 1.89 2.14 6.17 '6.45
80% 1.65 1.65 1.81 2.96 5.76
90% 1.23 0.90 1.73 2.63 3.50
95% 1.23 0.90 1.65 2.47 1.94
99% 1.23 0.90 1.65 1.99 J.53

November
3.37
3.09
2.88
W
2.14
1.81
\.73
\.60
1.51

December
2.92
2.63
2.22
2.06
1.89
1.65
1.56
1.48
1.40

J,I
4.74
2.98
W
2.02
1.23
0.86
0,53
0.32
0.12

Au usl
5.76
3.87
3.25
2.84
1.77
0.90
0.70
0.58
0.31

Se tember
4.11
3,70
3.04
2.76
1.89
1.32
1.23
0.88
0.74

October
4.94
4.06
3.87
3.37
2.30
1.65
1.35
1.23
1.17

June
25.67
19.74
14.40
9.87
1.89
0,99
0.66
0.53
0.16

Red Dirt Cree.c Estimated Stream Flow

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4
3.5
3
2.5
2
1.5
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FEB

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Am

M<Y

JUN

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51"

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Month

Table 2 above shows that the summer and winter recommendation of 1.75 cfs is available from
August 15th to June 14th The summer recommendation was reduced to 1.25 cfs June 15th to
August 14th based on limited water availa'Jility.

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