www.developpement-durable.gouv.fr

Ministry of Ecology, Sustainable Development and Energy

France – UK Workshop on Resilience to Severe Weather

21 October 2015

Flood forecasting in France

Isabelle LELEUSCHAPI

(Central Service for Hydrometeorology and Support to Flood Forecasting)

General Directorate for Risk Prevention

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Flood Forecasting in France

The « Vigicrues » system today

Plans for tomorrow

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The « Vigicrues » system today (1) A flood vigilance map : provides risk levels on the river

sections that are monitored by the State services (~22000 km)

4 colours used :

With vigilance reports, at both national and local levels, when possible including forecasts (expected values of water level or flow)

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The « Vigicrues » system today (2)

Access to real time data

> 1500 water level or flow stations

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The « Vigicrues » system today (3)

The vigilance information is updated at least twice a day (at 10:00 am and 4:00 pm)

Vigilance maps and reports (with forecasts) are made available to the public via the Internet :

http://www.vigicrues.gouv.fr

They are simultaneously pushed to the civil security and local authorities

→ The « Vigicrues » system is regularly updated and extended in a process of continous improvement and progress, and through feedback on past events.

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Plans for tomorrow (1)

The "Vigicrues" system currently gives satisfaction but improvement needs were expressed by different types of users :

Publish graphs combining water level (or flow) observations and forecasts

Predicting areas likely to be flooded (in connection with the water level forecasts)

Better warn people about the risk of flash floods

Develop custom services on mobile

→ Major projects have been carried out for several years to meet these needs.

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Plans for tomorrow (2)Predicting areas likely to be flooded

Flooded area scenarios in connection with 3 water levels at a given hydrometric station

Mapping of potential flooded areas related to Custines station

(Moselle river in France)

(scan25® from IGN ; potential flooded areas from

©DREAL Lorraine / SPC Meuse-Moselle)

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Prefects are informed

Plans for tomorrow (3)Better warn people about the risk of flash floods

Observed rainfall amount (from radar data)

Automatic hydrological modelingin each river basin and comparison of predicted flow with critical thresholds

River basins expected to

exceed threshold

Automated Flash Flood warning Automated Flash Flood warning sent to concerned municipalitiessent to concerned municipalities

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Plans for tomorrow (4) Early 2016 :

Graphs combining observations and forecasts on « Vigicrues » website

Potential flooded area maps produced for > 20 % of our forecasting points (~1400 municipalities are already concerned)→ first access restricted to local authorities

End of 2016 : Opening of the automated Flash Flood warning service

Later (2017/2018) : A more ergonomic « Vigicrues » website offering a wider range

of services

With custom services on mobile

→ To better assist the national and local authorities, communities, economic actors, stakeholders and individuals in crisis management

www.developpement-durable.gouv.fr

Ministry of Ecology, Sustainable Development and Energy

Thank you !

Tarn river in Arthès (Tarn, France) - Nov 2011