The use of integrated modelling in an urban water system and its influence on flood estimation

摘要: In an urban catchment there are several systems present: a sewer system (a combined or separate system), receiving water body and surface flood pathways created during extreme events. Regulating flooding is very complex because of the interactions between and the system. Presently each policies regulates different part water system, but no that consider as whole. practice this can easily lead to problems. If levels too high can be no free discharge overflow, resulting in backwater These backwater effects cause area if storage filled by a rainfall event. Furthermore overflows have significant effect on peak discharge body. To determine impact models used which calculate scenario occurs average once every few years, so called design-event. If flooding caused by interaction it unclear which design-event should be assess risk return period event, because multiple types events. Although possible occur subsystems catchment, water often modelled without little cross-reference other, although more complicated situations this may required. whether integrated modelling influence design case study was performed. The study industrial De Vosdonk Etten-Leur, town Dutch province Noord- Brabant. Near frequent problems with due limited capacity of insufficient capacity system. The objective compare methods integrated modelling determine the periods near the Vosdonk. There available, their own strengths and weaknesses:  The run separately allow for using level hydrographs, this method easy set up, number iterations required increase the accuracy method, calculation times higher than other methods.  Coupling existing framework. A relatively new modelling framework Open Modelling Interface (OpenMI). At moment, only case studies been done OpenMI none them in the Netherlands.  Fully models. difficult create software limitations, they finished use. main difficulty creating fully current cannot were not built integration mind. To which method preferable the urban system, evaluated of criteria. Since hydrographs fully integrated model gave memory errors long simulation periods, framework OpenMI was preferred study. The calculated floods determined timeseries of precipitation data measurement stations near area. Using fifteen years of precipitation data, two calculations first one stand-alone calculation second using the OpenMI. in both compared small, significant, of floods model. Although did not change much using modelling, depth increased stand-alone calculations. The “stand-alone” already uses simple schematization urban area proved good estimation body. From results concluded no added value when policy based frequency of flooding, since events. However, the policy risk, importance, depths increase added receiving water incorporate the sewer give insight outflow from body. Policy makers plans need plans. necessary to determine how sensitive subsystems. Since this showed influences total will likely case in areas well, especially those similar characteristics Vosdonk. Future research focus characteristics, such smaller catchment compared size, well.