7945

• UCREFRP Catalog Number: 7945
• Author: Bovee, K. D. and T. Cochnauer.
• Title: Development And Evaluation Of Weighted Criteria Probability-Of-Use Curves For Instream Flow Assessments
• USFW Year: 1977.
• USFW - Doc Type: Fisheries, Instream Flow Information Paper No. 3.
• Copyright Material: NO

approximately 40% of the redds. Movement of the 40 mm gravels would
result in destruction of 78% of the redds, etc. The same technique was
used~for other trout and salmon species.
Equation (5) was again utilized to determine the critical depth for
a given slope. .Again, critical tractive forces were obtained from Chow
(1959) or Leopold et aT. (1964).
EVALUATION CRITERIA
Because of the varying types of data used in the construction of
the probability curves, some curves may be used with confidence for
any level of instream flow assessment, while others should be used
judiciously for only reconnaissnce level studies. Therefore, accompan-
ying each set of probability curves is an outline matrix (see page )
describing: (1) source material used in the construction of the curve,
(2) analysis technique(s) used (frequency analysis, parameter overlap,
etc.), (3) IFG evaluation rating, (4) Comments concerning specific
curves, and (5) references cited.
The IFG evaluation for each curve was developed by strict adherence
to the following criteria and guidelines:
I. Excellent
A. Frequency analysis utilizing at least 200 individual measure-
ments, with samples collected over a wide range of hydraulic
parameters and combinations of parameters.
B. Laboratory experiments with >200 replications, covering
a wide range of hydraulic conditions.
C. X2 test of optimum showing p<0.10 of significant difference of
frequencies within optimum.
II. Good
A. Frequency analysis with suspected sampling bias; <200 measure-
ments, or range of hydraulic conditions limited.
B. Frequency analysis using a mix of measured and calculated
parameters; at least 100 measurements from a wide range of
hydraulic conditions.
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