Measurement of the changes in heads initiated by a valve closure are used t
o calibrate the friction factors in a hydraulic system consisting of a seri
es-connected pipeline and a downstream valve joining two reservoirs. The ca
libration is performed by minimizing the inverse least-squares problem repr
esenting the difference between the measured and predicted transient respon
se in the network. The hydraulic transient is modeled using the method of c
haracteristics. Unlike previous approaches, the sensitivity information req
uired for the minimization or error is obtained by direct differentiation o
f the method of characteristic equations and the valve equation with respec
t to the friction factors. The sensitivity of the calibration results to th
e amount of data included in the analysis, the initial friction factor esti
mates, and modeling and simulated measurement errors is discussed.