Hydrodynamic simulation of the operational management of a proposed flood emergency storage area at the Middle Elbe River
2008
Förster, Saskia | Chatterjee, C (Chandranath) | Bronstert, A (Axel)
Emergency storage areas can be an effective structural flood protection measure. By their controlled flooding the risk of inundation for downstream areas with higher vulnerability can be reduced.In the present study, the flooding and emptying process of a proposed storage area at the Middle Elbe River is simulated. The storage area has a maximum capacity of 40 million m³ and is divided into two polder basins. It is designed for the attenuation of extreme floods of 100 years or more return period.A one-dimensional hydrodynamic model is set up for a 20 km reach of the Elbe River, wherein the storage area is schematised by two storage cells each representing one polder basin. Flow between the storage cells and the Elbe River is controlled by adjustable gates, which operate based on the pre-defined conditions.Four flood scenarios which differ in flood magnitude and hydrograph shape are simulated. The scenarios are derived from analyses of a 70 years discharge record. Furthermore, for each flood scenario two gate control strategies are investigated.The results show that during large floods the utilization of the storage area with controlled gate operations significantly reduces the Elbe River peak discharges. However, the magnitude of the attenuation depends on the steepness of the flood hydrograph and the applied control strategy with well-timed gate operations.
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