BOARD00087

• Board Meeting Date: 1/27/2004
• Description: ISF Section - Instream Flow Appropriations - North Fork West Creek
• Board Meetings - Doc Type: Memo

Hydrologic Data

After receiying the cooperating agency's biologic recommendation, the CWCB and BLM staff,
conducted an eyaluation of the stream hydrology to determine if water was physically ayailable
for an instream flow appropriation. Although there is a substantial amount of streamflow gage
data ayailable for the Uncompahgre Plateau and Glade Park, most of this data is seyerely
impacted by diyersions and irrigation use. This situation makes it difficult to estimate the natural
flow regime for the watersheds on the Plateau. Without specific gage data to eyaluate, the next
best approach is a regional equation that estimates annual flow characteristics. The USGS has
deyeloped regional equations (Estimation of Natural Streamflow Characteristics in Westem
Colorado, Water Resources lnyestigations Report 85-4086, 1985) that apply to the Uncompahgre
Plateau and Glade Park based on basin drainage area, mean annual precipitation, mean basin
e1eyation and mean basin slope. The report "Uncompahgre Plateau and Glade Park Annual
Hydrograph Estimation" in Appendix C, explains staff's water ayailability analysis in more
detail. Table 2 below displays the estimated stream flow of North Fork West Creek.

Table 2: Estimated flow North Fork West Creek.

January
0.42

February
0.91

March
1.3

April
20

M',
72

June
33

July
1.7

August September October November December
0.65 0.54 0.51 0.5 0.46

North Fork West Creek Estimated Stream Flow

5

4

3

J!!
u

2

1

o

JAN

FEB

M'\R

Affi

M'\y

JUN

JUL

AUG

SEP

OCT

NOV

CEC

Month

Table 2 shows that the summer flow recommendation of 3.7 cfs is only ayailable April 1"
through June 30th. Table 2 also shows that the winter flow recommendation of 0.8 cfs is only
ayailable from July 1" through July 31" and February 15th through March 31". The winter flow

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