Cottonwood Creek Appendices

• Case Number: 05CW0149
• Stream Name: Cottonwood Creek
• Water Division: 4
• Water District: 60
• County: Montrose
• Instream Flow App - Doc Type: Supplemental Data

Table 1: Data
Part)'
III.M

Hall'
7/18/1995

o
1.48

250.Yo--IO%
3.7 - 0.6

SummcfO/Jl
2.9

Wirllcr t2lJl
1.6

Ill.M -IlUltduufl.anJ ~l.m.lgnntnl uow. UI\"IS101l0fWlldhfe
IIII'INIC'''''' th..... Ol,I'~llk of the accura..:y range or MdI\I1l1l!l" I:qUllIlOll ? - Cllttn" tM;'Vtr met In K2CROSS Stagmg Tablt

IJiolol?ie Flow Rec()mmendation
The summer flow recommendation. which meets 3 of 3 criteria anJ is within Ihe accuracy range
of the R2CROSS moJcI is 3.0 cfs. It is our belief that recol1unenJations that fall outside oflhe
accuracy range of the model. over 250% of the measured discharge or under -10% of the
measureJ Jischarge may not give an accurate estimate of the necessary instn:am I1mv requin:d.

Hydrologic Data

Allcr receiving the cooperating agency's biologic recommendation. the CWCB stall' conducted
an evaluation of the stream hydrology to detcnnine if water WlIS physically available for .HI
instream I1m\' appropriation. The hydrograph beluw was derived from Jata collected by the
USGS stream gage for Cottonwood Creek. CO (Ill #0(174500). \vhich has a drainage area or
3X.X square miles (See Gage Summary in Appendix C). The drainage arcll of the Cottonwood
Creek upstream of Linle Cottonwood Creek is approximately 24.0 square miles and the tolal
drainage area or the Cottonwood Creek upstream or the San ~liguel River is ilPproximatcly 47.2
square miles. The period of record for this gage was 1942-1951. the period of record used by
stair in their analysis was 1942-1951, or 10 years of record. Table 2 below displ<lYs the stream
now of Cottonwood Creek. in terms of a percentage of exceedence.

Tdblt 2. Slttam 110'" Conon"'utJd Cft~k

Exceedences Jan Feb Ma, Ap, May Jun Jul Aug Sep Oct Nov Oee
1% 0.3 1.0 11.2 131.5 123.7 30.0 1.8 6.8 1.5 0.7 0.5 0.3
5% 0.3 1.0 1.5 93.5 71.5 16.0 1.2 0.7 0.3 0.5 OA 0.2
10% 0.3 1.0 1.5 69.0 56.0 12.0 1.0 0.5 0.3 OA 0.3 0.2
20% 0.1 0.1 OA 51,0 42.0 7.3 0.7 OA 0.3 0.3 0.3 0.2
L60'!.. '0:1-0.'-0.1_1.4.0_1~0_2.2-D.<!-!l.2_0.2_0~0.1_0:1:1
80% 0.0 0.0 0.0 1.1 7.1 1.1 0.3 0.2 0.1 0.1 0.0 0.0
90% 0.0 0.0 0.0 0.0 5.3 0.7 0.2 0.1 0.1 0.1 0.0 0.0
95% 0.0 0.0 0.0 0.0 3.8 OA 0.2 0.1 0.1 0.1 0.0 0.0
99% 0.0 0.0 0.0 00 1.8 0.3 0.1 0.1 01 0.0 0.0 0.0

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