Values of calibration parameters embedded in open-channel flow equatio
ns normally are ascertained using observation data that often contains
Gaussian noise. These values subsequently suffer from induced errors
even if they are determined by using optimization methods. If these pa
rameters are to be considered a reliable representation of their true
values, investigations are needed to establish their response to a ran
ge of factors, such as data errors, through statistical methods. A sys
tematic study was carried out by a set of synthetic database for effec
tive control of test conditions and by using typical flood events. The
investigations showed that the identified parameters could be affecte
d by such factors as data error, objective function, or gauge sites. H
owever, through a better understanding of the behavior of the induced
errors the mean of the identified parameters was found to lie within a
prescribed confidence interval that contained the true value, even in
the presence of high noise levels. Selection of objective function wa
s found to be prone to undue biases affecting the identified parameter
s, which could be avoided through a careful consideration of the probl
em.