Past flooding data Belgium Wouter Vanneuville 19-05-2011 CRED, Brussels

Outline Belgium? Flanders? Sources of data about past floods Conclusions Database

Belgium? or Flanders? Meteorology: B Water level / flood predictions: regions Water management: regions ( + provinces, cities and villages, …) Crisis management (civil security): B (+ provinces, cities and villages Decree on integrated water management: Flanders Law on natural hazards (insurance): federal Belgium

Belgium? or Flanders? For this presentation: Partim past floods: Belgium Partim database: Flanders

Past floods

Past floods Weather events (1901-2000) Floodings due to rainfall Floodings due to storm tide (to a limited extend) Quantitative: mm rainfall Qualitative: flood impact “no information” for calibration of flood hazard and risk maps as defined in EU Floods Directive

Past floods Zenne catchment (part of river Scheldt basin, incl. city of Brussels) 1900-1974 Very detailed in its description Limited quantitative information

Past floods Socio-economic evaluation of the 1995 floods Focus on tangible effects Not only direct damage, insured damage, households and agriculture Belgium

Past floods Evaluation of tools Flood delineation Flood damages Results of models compared with data from the disaster fund No perfect match!

Past floods municipality level versus (sub)catchment Public goods Franchise influencing number of file records?

Conclusions – past floods Preliminary exercise! Heterogeneity of source data used Focus on rainfall driven events We got a file with 23 events 1 unknown 44 new subjective selection based on descriptions 12 information added Mostly qualitative information

Database Belgium: CALIS (Service public fédéral Intérieur - Direction des Calamités) Since 1993 Event and impact 65000 records

Database Flanders: Recently flooded areas (ROG) ROG information since 1988 (first compiled in 2000) Event information GIS layer (vector)

Helicopter with WES cam makes movie during flood Database Collection of information: Topographic maps given to municipalities to draw contours Helicopter with WES cam makes movie during flood Interpretation of images by Agency for Geographic Information Flanders (AGIV), since 2007

Database Collection of information: “Correction” of information based on digital elevation model (DHM Flanders) 2010-2011: Coordination Commission for Integrated Water Management (CIW) visits all- affected municipalities, information directly drawn on computer Impact information is collected as well (water levels above doorstep, damages, …)

Floods in Flanders 10/2009: river IJzer Return period Q IJzer (main river): > 100year Flooded area > 30km² - Damage limited

Flood maps LOT Foto overstroming rond sluis Lot (14/11/2010 14u) Overstromingskaart omgeving Lot (14/11/2010 14u)

30/11/2009 AGIV - WATLAB Samenwerking met AGIV-Robberechts Rampenfonds – Afijken Modellen – Snel overzicht voor beheerders AGIV - WATLAB 18

Conclusions Different databases at different levels Detailed event information separated from detailed impact information Different reactions on collaboration with insurance industry since ‘law on natural hazards’ came into force