Author(s): Kristof De Vleeschauwer; Jelle Weustenraad; Vincent Wolfs; Patrick Willems
Linked Author(s): Patrick Willems
Keywords: Conceptual model; Green zone; River; Sewer inundation; Storm water basin
Abstract: This article presents research on the effect of different types of storage options up- and downstream along the sewer system and on the receiving river for the case study of the city of Turnhout, Belgium. The first option consists of storage and infiltration of storm water in open green zones spread over the area of the city. The second option is the installation of storage reservoirs downstream the sewer system, just upstream of the overflows or outlets to the receiving river. The third option is one large storage reservoir downstream the river. The effect of each of these options on the peak flows and flood conditions along the sewer system and the river were studied. This was done by means of statistical postprocessing of long term simulation results using a 100-year rainfall series. To reduce the simulation time, conceptual models have been set up for the sewer network, the catchment runoff and the river system. The conceptual sewer and river models were calibrated to detailed full hydrodynamic models. The results show that the storage in the green zones strongly reduces the flood volumes along the sewer network. When about 1% of the total runoff area of the city is combined with storage in green zones, the sewer flood volume reduces with 30% to 50% . The impact of these green zones on the peak flows in the downstream river is, however, negligible. Storage reservoirs downstream the sewer system have a stronger effect. They strongly reduce the peak flows entering the river. However, due to the time shift between the sewer and river peak flows, this only has small effect on the river peak flows. Downstream river storage was found to have a larger effect.
Year: 2013