BOARD00154 ‎(2)‎

• Board Meeting Date: 3/13/2007
• Description: ISF Section - Notice of 2008 Instream Flow Recommendations and Summary of ISF Workshop
• Board Meetings - Doc Type: Memo

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DRAFf INSTREAM FLOW RECOMMENDATION

Mr. Dan Merriman
Colorado Water Conservation Board
1313 Sherman Street, Room 721
Denver, Colorado 80203

Dear Mr. Merriman:

The Bureau of Land Management (BLM) is writing this letter to formally communicate its
instream flow recommendation for Black Sulphur Creek, located in Water Division 6.

Location and Land Status. Black Sulphur Creek is tributary to Piceance Creek near Rock
School approx.imately 20 miles southwest of Meeker. This recommendation covers the stream
reach beginning at the confluence with Canyon Creek and ex.tends downstream to the headgate of
the Duckett Ditch. Approximately 65% of the 5.12-mile reach is federally owned, while the
remaining 35% is privately owned.

Biological Summary. Black Sulphur Creek is a low gradient stream with small substrate and a
stable channel. Cover, water temperatures. and food supplies are good for salmon ids, but fish
habitat is impacted by both natural and human-caused erosion. The stream supports a self-
sustaining population of Colomdo River Cutthroat Trout. The genetic quality of these trout
appears to vary, with some evidence of cross breeding with rdinbow trout evident. Because this
habitat is remote and sepamted from other water bodies by physical baniers and diversions that
dry up the creek downstream from the proposed reach, the creek has the potential to serve as a
reintroduction site for genetically pure Colorado River Cutthroat Trout. The riparian community
is vigorous and diverse, providing sufficient cover for maintaining water temperatures suitable
for salmonids even during low flow, high temperature periods.

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.

] .6 cubic feet per second is recommended for the high temperature period from May I to
October 31. This recommendation is driven by the average velocity criteria and wetted
perimeter criteria. Many portions of this reach have large substrate, and it is important to
provide adequate velocity and physical habitat in this type of environment 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.

1.2 cubic feet per second is recommended from November 1 through April 30. This
recommendation is driven by the average depth criteria. This flow rate win allow fish to
survive in pools, provide sufficient physical habitat in riftles between pools, and will
prevent the riparian environment from being seriously stressed.