10 ‎(2)‎

• Board Meeting Date: 11/18/2007
• Description: ISF Section - Uncontested 2007 Instream Flow Appropriations
• Board Meetings - Doc Type: Memo

Iti' RIiPLY R8I'IiR lY):
February 10, 2006
BUREAU OF LAND MANAGEMENT
Colorado State Office
2850 Youn~fielci Street
Lakewood, Colorado 80215-7093
Mr. Dan Merriman
Colorado Water Conservation Board
1313 Sherman Street, Room 721
Denver, Colorado 80203
Dear Mr. Merriman:
U.S. DEPARTMENT OF THE INTERIOR
BUREAU O~ LANG MANAGEMENT
www.co.blm.gov
The Bureau of Land Management (BLM) is writing this letter to formally communicate its
instream flow recommendation for Willow Creek, located in Water Division 6.
Location and Land Status. Willow Creek is tributary to the Little Snake River north of the
Colorado-Wyoming border. This recommendation covers the stream reach beginning at the
confluence with Spring Creek and extends downstream to the headgate of the Willow Creek
Ditch. Approximately 52% of the 3.95-mile reach is federally owned, while the remaining 48%
is privately owned.
Biological Summary. Willow Creek is a moderate gradient stream with small substrate and a
stable channel. Water quality, cover, and aquatic insects are good for supporting native fish
populations. Fish surveys indicate that the stream supports self-sustaining populations of
speckled dace, mottled sculpin, white sucker, minnow, and creek chub. This diversity of native
species is unusual on streams managed by BLM in northwest Colorado.
R2Cross Analysis. BLM's data analysis, coordinated with the Division of Wildlife, indicates
that the following flows are needed to protect the fishery and natural environment to a reasonable
degree.
2.6 cubic feet per second is recommended for the high temperature period from April 1 to
August 31. This recommendation is driven by the average velocity criteria and wetted
perimeter criteria. It is important to provide adequate velocity and physical habitat during
this time for fish spawning and incubation of eggs. Protecting flows during this time
period is also important for recharging the alluvial aquifer, which discharges water to the
stream and maintains flow levels during later summer.
United States Department of the Interior