Use of raingauges network data in the short term prediction of

urban pluvial floodsI) Methods of interpolationII) Cloud trackingIII) Future Work : radar images & Flood modelling

Maureen Coat ENSTA Paristech

Database available : 88 Raingauge Stations Rainfall Rate every 30 min Between 06/06/2006 and 19/10/2009

Rainfall Data

42 Raingauge stations in London :

Code in SQL , easy selection of rainfall rate: At any date At any time In London

Only a discrete set of data… But rainfall is a continuous phenomenon => Interpolation in regular grid cells

Many methods exist : Inverse Distance Weight Liska’s Method Polygone of Thiessen …

The more efficient : Kriging Method : Designed for geophysical variables with a

continuous distribution Based on statistics => Many data are required (Database) With Matlab

Methods of interpolation

Rainfall Rate Interpolation in London : (07/07/2009)

The 07/07/2009 : Flash flood in London

Victoria Station , Edgware road, and Paddington have been evacuated

Cloud Tracking ?

Rainfall Rate (mm/h) in London (07/07/2009) :

Victoria Station Latitude : 51.5104444 Longitude : 0.1872222

Rainfall Rate (mm/h) in London (07/07/2009) :

Rainfall Rate (mm/h) in London (07/07/2009) :

Rainfall Rate (mm/h) in London (07/07/2009) :

Rainfall Rate (mm/h) in London (07/07/2009) :

Weather radar : Estimated rainfall rates are derived

indirectly from measurements of reflectivity => subject to a combination of systematic

and random errors Conditional Merging ?

Future work :Comparison with radar images

Bemus (Belgrade Model of Urban Sewers) : Rainfall Data is in Input

Influence of intensity Influence of interpolation Method

Flood modelling :

Thank you for your attention

Maureen Coat maureen.coat@ensta.fr