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| Titel |
On the sensitivity of urban hydrodynamic modelling to rainfall spatial and temporal resolution |
| VerfasserIn |
G. Bruni, R. Reinoso, N. C. van de Giesen, F. H. L. R. Clemens, J. A. E. ten Veldhuis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-04), S.691-709 |
| Datensatznummer |
250120617
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| Publikation (Nr.) |
 copernicus.org/hess-19-691-2015.pdf |
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| Zusammenfassung |
Cities are increasingly vulnerable to floods generated by intense rainfall,
because of urbanisation of flood-prone areas and ongoing urban
densification. 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 cities. In this paper, a detailed study of the
sensitivity of urban hydrodynamic response to high resolution radar rainfall
was conducted. Rainfall rates derived from X-band dual polarimetric weather
radar were used as input into a detailed hydrodynamic sewer model for an
urban catchment in the city of Rotterdam, the Netherlands. The aim was to
characterise how the effect of space and time aggregation on rainfall
structure affects hydrodynamic modelling of urban catchments, for
resolutions ranging from 100 to 2000 m and from 1 to 10 min.
Dimensionless parameters were derived to compare results between different
storm conditions and to describe the effect of rainfall spatial resolution
in relation to storm characteristics 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 that for rainfall resolution lower than half the catchment
size, rainfall volumes mean and standard deviations decrease as a result of
smoothing of rainfall gradients. Moreover, deviations in maximum water
depths, from 10 to 30% depending on the storm, occurred for rainfall
resolution close to storm size, as a result of rainfall aggregation. Model
results also showed that modelled runoff peaks are more sensitive to
rainfall resolution than maximum in-sewer water depths as flow routing has a
damping effect on in-sewer water level variations. Temporal resolution
aggregation of rainfall inputs led to increase in de-correlation lengths
and resulted in time shift in modelled flow peaks by several minutes.
Sensitivity to temporal resolution of rainfall inputs was low compared to
spatial resolution, for the storms analysed in this study. |
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