Updating the original urban Sobek model with the rural area of Culemborg. This update is done with aid of digital information, field experiences and two 'old' Duflow models.
Modeling of the urban area in a Sobek-model: Pilot Culemborg
Hydrological models are used by the water board to test the rural areas on inundation standards, national water management agreement (NBW). In the future also urban areas should be tested on these standards. Nevertheless, in the existing models the urban areas are only schematized in a simplified manner. It is necessary to model the urban areas more sophisticated before testing on the inundation standards. The aim of this study is to find out which manner is the best to provide the existing models of an update. Especially about the method, the pros and cons of the actualization, required time and collecting information. The Sobek model of the urban area of Culemborg is used as a pilot during this study.
Information of the urban water system is available in four different data sources: two ‘old’ Duflow models, field experiences, digital information (Legger) and the existing Sobek model. The locations of the reaches and hydrological structures are analyzed for the different data sources. This resulted in three different maps. These maps were mutually compared and resulted in a new map, where duplications were omitted. The latest map is used to update the existing Sobek model.
During the study it became clear that it is hard to define one manner as the best. It became clear that using only one data source for updating the original model is not sufficient enough. Information from the Duflow models was not representative enough, due to the fact that a new neighborhood was taken into account. Information from the Legger was not sufficient enough; because essential information about hydrological structures was not always available. Therefore, the choice was made to use different data sources for updating the original model. The original model and the updated model are calculated for the period of 1 March till 1 June 2004. The results of both models are compared to nine different locations on the water level, velocity and discharge. These locations are based on the main discharge routes in Culemborg. Results of the updated model show that peaks in water levels, velocities and discharges are simulated higher in comparing with the original model. Next to this also the troughs in the water levels, velocities and discharges are smoother simulated.