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Composietbuien als neerslaginvoer voor rioleringsberekeningen
Vaes, G.; Berlamont, J. (1996). Composietbuien als neerslaginvoer voor rioleringsberekeningen. Water 15(88): 143-148

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  • Vaes, G.
  • Berlamont, J., meer

    Since the beginning of dynamic computer simulations for sewer systems, single storm events have been used as rainfall input. As a heritage, this has been copied for impact calculations. However, it is not so that the frequency of an overflow event equals the frequency of the storm which will just lead to an overflow event. This is true for linear systems, but sewer systems often behave in a very non-linear way. So single storm events can only give a rough estimation of the overflow frequency. Most often the overflow frequency is strongly underestimated. The single storm events which are used at the moment for impact calculations are taken from the UK and do not satisfy the IDF-relationships (Intensity/Duration/Frequency-relationships) which were recently developed for Flanders based on new, detailed rainfall data. Therefore new single "composite" storms were developed. Each of these single storm events has a certain frequency and can be used instead of a whole series of storms with different durations. Therefore they are called composite storms. Besides, these storms include antecedent and posterior rainfall, which are checked with these of historical storms: the mean values satisfy, but the variability is high. The antecedent and posterior conditions of the historical rainfall data have similar characteristics, therefore symmetric storms are assumed. The major advantage of these composite storms is that they are much easier to use: the critical storm duration has not to be know anymore. There is also a benefit: we can obtain more information within the same simulation time. The same type of composite storms can also be used for design purposes.
