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# The relative delay times of catchment model storages

thesis

posted on 2017-02-08, 03:39 authored by Soste, Leon IlgvarThe original aim of this research was to determine the best means
of calculating the relative delay time parameter of the Laurenson runoff
routing method of flood estimation. Early testing conducted as a part of
achieving this end showed that the model could be quite insensitive to the
means used to calculate relative delay. Model sensitivity to the means
of calculating this parameter had apparently not yet been verified, and
if it was insensitive, the best means of calculating the parameter was
not required. Hence it was decided to test the thesis that the model was
insensitive to the means of calculating the relative delay time parameter.
The thesis was tested by applying the model to a range of flood sizes
on two catchments using five different means of calculating relative delay
time. The differences in model output produced by these delay hypotheses
were examined in relation to the average model error. In a number of cases
the effects on model performance of these different delay hypotheses were
quite small, but in other cases they were quite large. Hence the conclusion
had to be drawn that the model is sensitive to the means of calculating
relative delay time. The fact that the means of calculating relative delay.
time Has unimportant in a conditional sense left the possibility that the
model could be used under these conditions, if they could be defined.
However, in the long term it meant that the best means of calculating
relative delay time was required.
During the course of the investigation a number of problems in relation
to model use were encountered. The attempts made to solve these problems
should provide useful information on model application in the future.