9605

• UCREFRP Catalog Number: 9605
• Author: Schmidt, J. C. and e. al.
• Title: Flow Recommendations for the White River, Utah-Colorado Draft Report.
• USFW Year: 2002.
• USFW - Doc Type: Logan, UT.
• Copyright Material: NO

Haines, and Tim Modde, U.S. Fish and Wildlife Service. The individual reports addressed

separate objectives and are presented as individual, complete studies that stand alone.

Study findings:

An integrated flow recommendation was determined through these two independent

stduies, one to evaluate the peak flows needed to maintain channel stability and diversity, and the

second to identify a minimum base flow needed to maintain habitat for the Colorado pikeminnow

population.

Channel maintenance flow/high flow recommendations: There are two approaches to

determining the discharges necessary to maintain channel diversity. One is to directly measure

channel bed movement measuring sediment transport and bed scour and fill in those parts of the

channel that are critical habitat. A second is to determine those discharges at which habitats are

maintained on typical alluvial streams. We pursued both in these studies.

Several lines of evidence indicated that a high-flow component of an instream flow

should preserve most of the natural flow regime greater than approximately 40 m3/s (~1 ,400

ft3/s).

Historical discharge and depth records at our study site near the Watson, Utah U.S. Geological

Survey gage showed that flows of this magnitude scoured the bed, and thus flows greater than

this were capable of transporting fine bed sediment. We inferred that bedload movement

occurred at 51 m3/s (1,800 ft 3/S), because bedforms were detected on fathometer traces at those

cross sections with fine-grained bed material at this discharge.

The White River is a sediment supply-limited stream, becau~e much more suspended

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