9708

• UCREFRP Catalog Number: 9708
• Author: Grand, T.C., S.F. Railsback, J.W. Hayse and K.E. LaGory.
• Title: A physical habitat model for predicting the effects of flow fluctuations in nursery habitats of the endangered Colorado pikeminnow ‎(Ptychocheilus lucius)‎.
• USFW Year: 2006.
• USFW - Doc Type: River Research and Applications
• Copyright Material: YES

FLUCTUATING FLOWS AND BACKWATER HABITATS

1135

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(c) 20% Flow Variation

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(d) 30% Flow Variation

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(e) 40% Flow Variation

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Figure 5, Simulated invertebrate availability (#, m -2) in backwater 5 as a function of within-day flow variation, daily mean backwater
temperature and the invertebrate flushing calibration parameter

over shOlt time intervals, This effect is likely due to our assumption t.hat mainst.em wat.er mixes completely as it
flows into the backwat.er during increasing river flow, and undoubtedly also reflects that. calibration data were
measured at one point in the backwater whereas the model simulated average temperature of the entire backwater.
In general, the water t.emperature model predict.s that, during the summer and fall, backwat.er temperat.ures t.end
to be lower than air temperature but higher than mainst.em water temperature. There is, however, daily variation in
this ranking depending on the backwater's size and the amount of mixing with the mainstem (Figure 6).

Invertebrate model sensitivity analysis

Of the three inputs evaluated, mean daily backwater temperature had the stTOngest and most direct effect on
invertebrate availability (p<O.OOI, r4f= 1,94 for each of the two backwaters). There were also significant
interactions between flow fluctuation magnitude and backwater temperature (p < 0,001, df = I, 94 for each of the
two backwaters) and fluctuation magnitude, backwater temperature and the flushing calibration parameter
(p <0.001, df=4, 94 for each of the two backwaters).

Copyright K;o 2006 John Wiley & Sons, Ltd,

River Res, Applic. 22: 1125-1142 (2006)
DOl: 10, I002!rra