4-02CW271 Supplemental Data

• Case Number: 02CW0271
• Stream Name: La Sal Creek
• Watershed: Gunnison
• Water Division: 4
• Water District: 61
• County: Montrose
• Instream Flow App - Doc Type: Supplemental Data

biologic instream flow recu11imendations. The CDOW has deten-ied that maintaining these
three hydraulic parameters at adequate levels across riffle habitat types, aquatic habitat in pools
and runs will also be maintained for most life stages of fish and aquatic invertebrates (Nehring
1979; Espegren 1996).
For this segment of stream, three data sets were collected with the results shown in Table 1
below. Table 1 shows who collected the data (Party), the date the data was collected (Date), the
measured discharge at the time of the survey (Q), the accuracy range of the predicted flows
based on Manning Equation (240% and 40% of Q), the summer flow recommendation based on
meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3
hydraulic criteria.
Table 1: Data
Party
Date
Q
250 % -40%
Summer (3/3)
Winter (2/3)
BLM
6/29/00
1.51
3.80 - 0.6
5.9(1)
3.0
BLM
7/19/95
6.58
16.4 - 2.6
4.1
2.2(1)
BLM
6/30/00
4.88
12.2 - 2.0
6.1
1.7(1)
BLM = Bureau of Land Management DOW = Div'sion of Wildlife
(1) Predicted flow outside of the accuracy range of Manning's Equation. ? = Criteria never met in R2CROSS Staging Table.
Biologic Flow Recommendation
The summer flow recommendations, which met 3 of 3 criteria and are within the accuracy range
of the R2CROSS model fall somewhere between 6.1 and 4.1 cfs (See Table 1). Averaging the
two summer flow recommendations gives a summer recommendation of 5.1 cfs. The winter
flow recommendations which meets 2 of 3 criteria and is within the accuracy range of the
R2CROSS model fall is 3.0 cfs (See Table 1).
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. There are no currently operated or historically operated
streamflow gages for this reach. The closest gage CWCB staff found was the gage located on
Roc Creek 11 miles North of the La Sal Creek drainage. The hydrograph below was derived
from data collected by the USGS stream gage for Roc Creek near Uranium, CO (ID #09179000),
which has a drainage area of 75.8 square miles. The drainage area upstream of Spring Creek is
approximately 69.5 square miles and the drainage area upstream of the Dolores River is
approximately 113 square miles. Staff used a basin apportionment method to estimate stream
flows above and below Spring Creek for La Sal Creek (See Gage Summary in Appendix C). The
period of record for this gage was 1944 to 1952, the period of record used by staff in their
analysis was 1944 - 1952, or eight years of record. Table 2 below displays the estimated flow of
La Sal Creek upstream of Spring Creek, in terms of a percentage of exceedence.
Table 2:
Exceedences
1%
5%
10%
20%
50%
80%
90%
95%
99%
Janua
Februar
March
April
Ma
June
Jul
August September October November December
6.69
10.76
18.81
202.08
171.55
103.42
20.65
14.38
4.18
7.70 r
6.60 -
7.57
6.42
7.46
11.00
153.12
97.74
67.85
13.94
6.97
3.21
6.42 ''-
5.87
5.68
6.42
6.42 `
9.17
116.44
79.40
44.93
9.35
3.49 '-
2.11
4.99
5.50
4.77
4.95
4.86
8.69
54.10
59.05
22.01
4.31
2.02
1.56
3.12 rr
4.95
4.13
3.67
4.58
5.96
15.59
23.84
6.60
1.38
1.38
1.19
1.56
2.57
3.03
2.35
2.93
3.67
10.09
7.06
2.20
0.64
0.55
0.73
1.19
1.10
0.64
0.73
2.38
3.12
6.33
3.87
1.19
0.46
0.37
0.46
0.92
0.64
0.09
0.73
2.20
2.09
4.40
3.12
0.55
0.37
0.28
0.46
0.83
0.37
0.00
073
2.11
1.65
2.75
2.02 0.46
028
0.18
0.28
0.73
0.13
0.00
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