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

1138

T, C. GRAND ET ilL

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Figure 9, Simulated daily minimum wetted area (m2) fix backwaters I (a), 2 (b), 3 (c), 4 (d), 5 (e) and 6 (f) at 0, 10,20,30 and 40% within-day
flow variation

Invertebrate availability

The proportion of daily invertebrate product.ion t.hat we calculat.e remains in t.he backwater after exchange with
the mainstem is strongly affected by the magnitude of within-day flow fluctuations and differs between backwaters
(Figure 10). The proportion of invertebrate production remaining mirrors the effects of flow fluctuations on the
propOltion of the backwater's mean daily volume exchanged with the mainstem and represents the direct effect of
backwater flushing on invertebrate availability. The effects are most pronounced in small, relatively shallow
backwaters (3, 4 and 5),
As a consequence of difTerences in the proportion of the backwater's daily volume exchanged with the mainstem
(and possibly smaU differences in backwater temperature, particularly during the first two months of the
simulation), invertebrate availabilit.y (d;) varies with the magnitude of within-day flow fluctuations (Figure I l).
Typically, as within-day flow fluctuations increase, invertebrate availability declines. This effect is .most
pronounced for small, shallow backwaters (backwat.ers 3, 4 and 5; Figure 11).

Copyright !(:' 20(J6 John Wiley & Sons, Ltd,

River Res, A.pplic, 22: 1125-1142 (2006)
DOl: IO,1002/rra