BOARD01130

• Board Meeting Date: 1/26/2000
• Description: ISF Section - Instream Flow Appropriations - Water Division 5
• Board Meetings - Doc Type: Memo

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the most upstream survey to the most downstream survey. Table I shows who collected the data
eparty), the date the data was collected eDate), the measured discharge at the time of the survey
eQ), the accuracy range of predicted flows based on Manning's Equation e240% and 40% of Q),
the summer flow recommendation based upon meeting 3 of 3 hydraulic criteria and the winter
flow recommendation based upon 2 of 3 hydraulic criteria.

Table 1: Data

Party Date 0 250%-40% Summer (3/3) Winter e2/3)
BLM 7/8/98 2.87 7.2 - 1.1 2.7 2.1
BLM 7/8/98 4.18 10.4 - 1.7 2.1 1.5(1)

BLM = Bureau orLand Management (I) Predicted flow outside of the accuracy range ofMannmg's EquatIOn.
? = Criteria never met in R2CROSS Staging Table.

Biologic Flow Recommendations
The BLM recommended a 2.3, 1.9 and 1.1 cfs summer flow and a 0.8 cfs winter flow based on
their July 8th, 1998, data collection effort and their water availability analysis. Staff has
reviewed the data collected by the BLM. The summer flow recommendations which meets 3 of
3 criteria and is within the accuracy range of the R2CROSS model fall somewhere between 2.7
and 2.1 cfs. Averaging the two summer recommendations gives a summer recommendation of
2.4 cfs. The winter flow recommendation, which meets 2 of 3 criteria and is within the accuracy
of the R2CROSS model, is 2.1 cfs.

Hydrologic Data

After receiving the cooperating agencies' 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 hydrograph was derived from data collected by the USGS
stream gage for East Fork Parachute Creek near Anvil Points (ID #09092960), which has a
drainage area of 14.5 square miles esee Gage Summary in Appendix C). The period of record for
this gage is 1976 to 1983, the period of record used by staff in their analysis was 1976-1983, or
seven years of record. The estimated drainage area of East Fork Parachute Creek upstream and
including Second Anvil Creek is approximately 8.1 square miles. The drainage area upstream of
First Anvil Creek is 11.7 square miles. Tables 2 and 3 below display the estimated flow of East
Fork Parachute Creek at the confluence with Second and First Anvil Creeks, in terms of a
percentage of exceedence. The blue shading highlights how often the summer and winter flow
recommendations have been available.

Table 2: E. Fk. Parachute Ck downstream of Second Anvil Creek
n n F M ,h A ril M Ju u Au ust tem r to r Nvm r D m ,
1 % ,2 1.1 7. 1. 1, 1.06 0,84 ,7
20% 0.41 0.51 1.12 10,06 53.07 11.73 2,57 1.28 0.78 0.87 0.61 0.51
50".. 0,35 0,39 0,56 3.30 22.07 4.08 1.45 0.84 0,56 0,55 0, 1 0,36
% ,21 .1 O. 2 ,56 ,19 .12 .1 .1