Print Email Facebook Twitter On the sensitivity of urban hydrodynamic modelling to rainfall spatial and temporal resolution Title On the sensitivity of urban hydrodynamic modelling to rainfall spatial and temporal resolution Author Bruni, G. Reinoso Rondinel, R.R. Van de Giesen, N.C. Clemens, F.H.L.R. Ten Veldhuis, J.A.E. Faculty Civil Engineering and Geosciences Department Water Management Date 2014-06-06 Abstract Cities are increasingly vulnerable to floods generated by intense rainfall, because of their high degree of imperviousness, implementation of infrastructures, and changes in precipitation patterns due to climate change. Accurate information of convective storm characteristics at high spatial and temporal resolution is a crucial input for urban hydrological models to be able to simulate fast runoff processes and enhance flood prediction. In this paper, a detailed study of the sensitivity of urban hydrological response to high resolution radar rainfall was conducted. Rainfall rates derived from X-band dual polarimetric weather radar for four rainstorms were used as input into a detailed hydrodynamic sewer model for an urban catchment in Rotterdam, the Netherlands. Dimensionless parameters were derived to compare results between different storm conditions and to describe the effect of rainfall spatial resolution in relation to storm and hydrodynamic model properties: rainfall sampling number (rainfall resolution vs. storm size), catchment sampling number (rainfall resolution vs. catchment size), runoff and sewer sampling number (rainfall resolution vs. runoff and sewer model resolution respectively). Results show catchment smearing effect for rainfall resolution approaching half the catchment size, i.e. for catchments sampling numbers greater than 0.5 averaged rainfall volumes decrease about 20%. Moreover, deviations in maximum water depths, form 10 to 30% depending on the storm, occur for rainfall resolution close to storm size, describing storm smearing effect due to rainfall coarsening. Model results also show the sensitivity of modelled runoff peaks and maximum water depths to the resolution of the runoff areas and sewer density respectively. Sensitivity to temporal resolution of rainfall input seems low compared to spatial resolution, for the storms analysed in this study. Findings are in agreement with previous studies on natural catchments, thus the sampling numbers seem to be promising as an approach to describe sensitivity of hydrological response to rainfall variability for intra-urban catchments and local convective storms. More storms and different urban catchments of varying characteristics need to be analysed in order to validate these findings. To reference this document use: http://resolver.tudelft.nl/uuid:8b805f3b-c30c-4bee-adfe-963e1ffa9a0d DOI https://doi.org/10.5194/hessd-11-5991-2014 Publisher European Geosciences Union ISSN 1812-2108 Source Hydrology and Earth System Sciences Discussions, 11 (6), 2014 Part of collection Institutional Repository Document type journal article Rights © 2014 The Author(s) 2014CC Attribution 3.0 License Files PDF 310199.pdf 1.81 MB Close viewer /islandora/object/uuid:8b805f3b-c30c-4bee-adfe-963e1ffa9a0d/datastream/OBJ/view