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

reworking by measuring sediment transport and bed scour and fill in those parts of the

channel that are important habitat. A second approach is to determine those discharges at

which habitat maintenance is known to occur, on average, in typical alluvial streams. We

pursued both approaches in this study.

The most widely accepted surrogates for establishing discharges necessary to

transport significant amounts of sediment and, thereby, maintain the channel are the

concepts of bankfull and effective discharges. Frequently occurring floods of moderate

magnitude transport the greatest amount of sediment and are believed to accomplish the

greatest amount of geomorphic work in alluvial rivers (Wolman and Miller 1960). While

extremely high discharges can carry huge amounts of sediment, large floods are rare, and

the majority of sediment is typically transported by more frequently occurring moderate

floods. The discharge that accomplishes the most geomorphic work is known as the

effective discharge. Andrews and Nankervis (1995) calculated effective discharge in 17

gravel-bedded streams, and found that effective discharge typically fell in the range of

0.8 and 1.6 times the bankfull discharge. Andrews (1980) found that the range of

effective discharges had a recurrence interval of between 1.2 and 3.3 years in the Yampa

River basin. The bankfull flood, because of this association with effective discharge, is

often used as an indicator of the moderate flood which typically creates the form of the

channel (Andrews and Nankervis 1995).

Background -- Geomorphic Research about the White River and Its relationship to the

Requirements of Endangered Fish

Although streamflows have been gaged in the White River basin since 1904, there
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