Using probabilistic radar rainfall nowcasts and NWP forecasts for flow prediction in urban catchments

2012 ◽  
Vol 103 ◽  
pp. 80-95 ◽  
Author(s):  
S. Liguori ◽  
M.A. Rico-Ramirez ◽  
A.N.A. Schellart ◽  
A.J. Saul
Keyword(s):  
Radar Rainfall ◽  
Flow Prediction ◽  
Urban Catchments

Sewer Flow Prediction at a Large Urban Scale: Influence of Radar Rainfall Spatial Resolution

2018 ◽  
pp. 794-798
Author(s):  
Sara Simona Cipolla ◽  
Giulia Paola Di Ventura ◽  
Marco Maglionico ◽  
Pier Paolo Alberoni ◽  
Attilio Castellarin
Keyword(s):  
Spatial Resolution ◽  
Radar Rainfall ◽  
Flow Prediction

Comparison of short-term rainfall forecasts for model-based flow prediction in urban drainage systems

2013 ◽  
Vol 68 (2) ◽  
pp. 472-478 ◽  
Author(s):  
Søren Thorndahl ◽  
Troels Sander Poulsen ◽  
Thomas Bøvith ◽  
Morten Borup ◽  
Malte Ahm ◽  
...  
Keyword(s):  
Real Time ◽  
Weather Prediction ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Waste Water Treatment Plant ◽  
Lead Times ◽  
Radar Rainfall ◽  
Drainage Systems ◽  
Flow Prediction ◽  
Time Flow

Forecast-based flow prediction in drainage systems can be used to implement real-time control of drainage systems. This study compares two different types of rainfall forecast – a radar rainfall extrapolation-based nowcast model and a numerical weather prediction model. The models are applied as input to an urban runoff model predicting the inlet flow to a waste water treatment plant. The modelled flows are auto-calibrated against real-time flow observations in order to certify the best possible forecast. Results show that it is possible to forecast flows with a lead time of 24 h. The best performance of the system is found using the radar nowcast for the short lead times and the weather model for larger lead times.

scholarly journals On the sensitivity of urban hydrodynamic modelling to rainfall spatial and temporal resolution

2014 ◽  
Vol 11 (6) ◽  
pp. 5991-6033 ◽  
Author(s):  
G. Bruni ◽  
R. Reinoso ◽  
N. C. van de Giesen ◽  
F. H. L. R. Clemens ◽  
J. A. E. ten Veldhuis
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
Rainfall Variability ◽  
Accurate Information ◽  
Hydrological Response ◽  
Radar Rainfall ◽  
Catchment Size ◽  
Maximum Water ◽  
Urban Catchments ◽  
Water Depths

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.

scholarly journals On the use of radar reflectivity for estimation of the areal reduction factor

2006 ◽  
Vol 6 (3) ◽  
pp. 377-386 ◽  
Author(s):  
F. Lombardo ◽  
F. Napolitano ◽  
F. Russo
Keyword(s):  
Reduction Factor ◽  
Radar Reflectivity ◽  
Medium Size ◽  
Small Scale ◽  
Natural Phenomena ◽  
Radar Rainfall ◽  
Areal Reduction Factor ◽  
Empirical Relations ◽  
Urban Catchments ◽  
Areal Rainfall

Abstract. In order to estimate the rainfall fields over an entire basin raingauge, pointwise measurements need to be interpolated and the small-scale variability of rainfall fields can lead to biases in the rain rate estimation over an entire basin, above all for small or medium size mountainous and urban catchments. For these reasons, several raingauges should be installed in different places in order to determine the spatial rainfall distribution during the evolution of the natural phenomena over the selected area. In technical applications, many empirical relations are used in order to deduce heavy areal rainfall, when just one raingauge is available. In this work, we studied the areal reduction factor (ARF) using radar reflectivity maps collected with the Polar 55C, a C-band Doppler dual polarized coherent weather radar with polarization agility and with a 0.9° beamwidth. The radar rainfall estimates, for an area of 1 km2, were integrated for heavy rainfall with an upscaling process, until we had rainfall estimate for an area of 900 km2. The results obtained for a significant amount of data by using this technique are compared with the most important relations of the areal reduction factor reported in the literature.

scholarly journals The role of storm scale, position and movement in controlling urban flood response

2018 ◽  
Vol 22 (1) ◽  
pp. 417-436 ◽  
Author(s):  
Marie-Claire ten Veldhuis ◽  
Zhengzheng Zhou ◽  
Long Yang ◽  
Shuguang Liu ◽  
James Smith
Keyword(s):  
Spatial Scales ◽  
Rainfall Variability ◽  
Flow Path ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Radar Rainfall ◽  
Peak Flows ◽  
Basin Scale ◽  
Urban Catchments ◽  
The Impact

Abstract. The impact of spatial and temporal variability of rainfall on hydrological response remains poorly understood, in particular in urban catchments due to their strong variability in land use, a high degree of imperviousness and the presence of stormwater infrastructure. In this study, we analyze the effect of storm scale, position and movement in relation to basin scale and flow-path network structure on urban hydrological response. A catalog of 279 peak events was extracted from a high-quality observational dataset covering 15 years of flow observations and radar rainfall data for five (semi)urbanized basins ranging from 7.0 to 111.1 km2 in size. Results showed that the largest peak flows in the event catalog were associated with storm core scales exceeding basin scale, for all except the largest basin. Spatial scale of flood-producing storm events in the smaller basins fell into two groups: storms of large spatial scales exceeding basin size or small, concentrated events, with storm core much smaller than basin size. For the majority of events, spatial rainfall variability was strongly smoothed by the flow-path network, increasingly so for larger basin size. Correlation analysis showed that position of the storm in relation to the flow-path network was significantly correlated with peak flow in the smallest and in the two more urbanized basins. Analysis of storm movement relative to the flow-path network showed that direction of storm movement, upstream or downstream relative to the flow-path network, had little influence on hydrological response. Slow-moving storms tend to be associated with higher peak flows and longer lag times. Unexpectedly, position of the storm relative to impervious cover within the basins had little effect on flow peaks. These findings show the importance of observation-based analysis in validating and improving our understanding of interactions between the spatial distribution of rainfall and catchment variability.

scholarly journals On the sensitivity of urban hydrodynamic modelling to rainfall spatial and temporal resolution

2015 ◽  
Vol 19 (2) ◽  
pp. 691-709 ◽  
Author(s):  
G. Bruni ◽  
R. Reinoso ◽  
N. C. van de Giesen ◽  
F. H. L. R. Clemens ◽  
J. A. E. ten Veldhuis
Keyword(s):  
Spatial Resolution ◽  
Temporal Resolution ◽  
Time Shift ◽  
Hydrodynamic Modelling ◽  
Radar Rainfall ◽  
Catchment Size ◽  
Urban Catchments ◽  
Storm Characteristics ◽  
Water Depths ◽  
Sewer Water

Abstract. 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.

scholarly journals The role of storm dynamics and scale in controlling urban flood response

2017 ◽  
Author(s):  
Marie-Claire ten Veldhuis ◽  
Zhengzheng Zhou ◽  
Long Yang ◽  
Shuguang Liu ◽  
James Smith
Keyword(s):  
Spatial Distribution ◽  
Spatial Scales ◽  
Rainfall Variability ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Radar Rainfall ◽  
Peak Flows ◽  
Basin Scale ◽  
Urban Catchments ◽  
The Impact

Abstract. The impact of spatial and temporal variability of rainfall on hydrological response remains poorly understood, in particular in urban catchments due to their high variability in land-use, high degree of imperviousness and the presence of stormwater infrastructure. In this study, we analyse the effect of rainfall spatial distribution with respect to basin scale and flowpath network structure on urban hydrological response based on a large, high quality observational dataset. A catalog of 279 peak events was extracted from 15 years of high resolution flow observations and radar rainfall data for five (semi)urbanised basins ranging from 7.0 to 111.1 km2 in size. Results showed that largest peak flows in the event catalog were associated with storm core scales exceeding basin scale, for all except the largest basin. Spatial scale of flood-producing storm events in the smaller basins fell into two groups: storms of large spatial scales exceeding basin size or small, concentrated events, with storm core much smaller than basin size. For the majority of events, spatial rainfall variability was strongly smoothed by the flowpath network, increasingly so for larger basin size. Correlation analysis showed that position of the storm in relation to the flowpath network was significantly correlated with peak flow in the smallest and in the two more urbanised basins. Analysis of storm movement relative to the flow path network showed that direction of storm movement, upstream or downstream relative to the flowpath network, had little influence on hydrological response variability. Slow-moving storms tend to be associated with higher peak flows and longer lag times. Unexpectedly, spatial distribution of imperviousness along the flowpath network did not significantly alter hydrological response in relation to spatial storm characteristics. These findings show the importance of observation-based analysis in validating and improving our understanding of interactions between rainfall and catchment variability.

Requirements for radar rainfall data in urban catchment modelling and control

1997 ◽  
Vol 36 (8-9) ◽  
pp. 13-18
Author(s):  
Georg Johann ◽  
Hans-Reinhard Verworn
Keyword(s):  
Radar Data ◽  
Rainfall Data ◽  
Rainfall Runoff ◽  
Radar Rainfall ◽  
Urban Catchment ◽  
Space Resolution ◽  
Time Space ◽  
Urban Catchments ◽  
The University ◽  
And Control

The use of radar rainfall data as input for storm runoff models can procure a real benefit if the hydrologic response of the watershed studied is strongly dependent on the spatial and temporal heterogeneity of precipitation over its area. In dynamic management of urban catchments rainfall runoff simulations are sensitive to the resolution of the input data. In this study the influence of varios time/space resolutions of radar rainfall data on the results of rainfall-runoff simulations is inverstigated. Therefore, X-band radar rainfall data with high resolution in space (0.5 × 0.5 km) and time (360° scan every second minute), are compared with radar data with 14 min time and 1 × 1 km space resolution as input for the HYSTEM/EXTRAN hydrodynamic model of a small urban catchment. The presented invstigations are realized within the research project “realtime control of a combined sewer system by radar estimates of precipitataon” carried out by the University of Hannover and the Emschergenossenschaft/Lippeverband.

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