Context
Recent flash flood events have affected the French Rivera (Côte d´Azur: Nice Metropolitan territory, Cannes,) as well as Corsica Island. Among the most significant flash flood events that occured in this region stand out:
• 2015 Oct.03 (Nice Metropolitan territory & Cannes)
• 2016 Nov.24 (Corsica Island, Bigugliga catchment)
• 2020 Oct.02 Alex storm (Nice Metropolitan Area – Vésubie valley)
• 2023 Oct.20 Aline storm (Nice Metropolitan Area – Vésubie valley)
The Var Catchment that includes the Vesubie sub-catchment is located in southeast France, in the French Riviera. The catchment covers the most of Alpes-Maritimes department as well as a small part of Alpes-de-Haute-Provence department. The catchment has a total area of 2.800 km2 and is characterized by a variation of altitude from 0 m at the Mediterranean Sea, to 3.132m at the mountain peaks of the Southern Alps.
In 2020, ALEX storm blew in from the Atlantic to impact France’s western coastline with wind gusts reaching as high as 180 km/h with rainfall of more than 500 mm registered over 24 hours in Saint-Martin-Vésubie. The rainfall was induced by three stationary convective cells that where never observed before in France. Damages in the Alpes Maritime region of southern France and the Nice area were estimated at more than US $1.75 billion, on an economic basis and with 9 victims. Extreme flood events like this have occurred in 1994 and 2015 as well. In these events, due to the fast-occurring flash floods, field measurements were often unavailable as measurement instrument were destroyed by the floods. Also, water pollution from the combined sewer overflow (CSO) systems and other industrial facilities added more challenges to the management and recovery from the flood. These types of flood event are typical representations in the Mediterranean coastal cities in France and Italy. The climate evolution analysis produced by Meteo France assume that this type of event could be more frequent in the coming years.
In 2023, the Aline Storm affected the Vésubie sub-catchment. Impacted again by a flash flood event this sub-catchment hydrological, hydraulic and hydrogeomorphological configuration requieres a step- back on the employed monitoring, modelling methodologies and tool for an in depth analysis.
Presentation
Flash Flood in France: Var and Vésubie Introduction
Video of the introduction presentation (recorded)
Accidnetal water pollution: introduction Var and Vesubie catchment
Basic data sets
DEM (EU-DEM 25 m resolution)
HR DEM (classified dataset) LiDAR HD(10pts/m2); from IGN: Vésubie and Boréon confluence at Saint-Matin de Vésubie
(Metadata in French:https://geoservices.ign.fr/documentation/donnees/alti/lidarhd)
CORINE Land cover 2018 (100m resolution; Copernicus Link)
CORINE Land cover 2018 (100m resolution French government website; Metadata in French)
Geological information:https://infoterre.brgm.fr/viewer/MainTileForward.do
Rainfall and gaging stations data sets
1- All the hourly rainfall data history for all the French stations can be downloaded there for 10 years duration period since year 1880 (for statistical analysis for the different stations of interest) : https://meteo.data.gouv.fr/datasets/6569b4473bedf2e7abad3b72 (type “departement_06” in the research bar) The description of the fields is accessible there https://www.data.gouv.fr/fr/datasets/r/5d0f9af9-149b-463a-9472-445dafb698d9 (FYI column RR1 is the one with the hourly rainfall quantity)
2- Event of the 10.02.2024 : Rainfall datasets 14 stations in the Var Catchment extracted from Meteo France eventshttps://drive.google.com/file/d/125v5NBhQSFwVm54g4Rw8JJkliShAvPHE/view?usp=sharing
3- the 2020-2021 (for the Alex storm) and 2022-2023 (for the Aline Storm) hourly rainfall dataset for all the department of Alpes-Maritimes rainfall gages station are stored for your convenience there.
https://drive.google.com/file/d/1RxXUhDyGUgjBwQMbJiGb6FC1YLFKE7ja/view?usp=sharing
4- Gaging Stations Napoléon III and Utelle bridges, Aline Storm (20.Oct.2023)
Literature
Brigode, P., Bourgin, F., Yassine, R., Delestre, O., & Lagrée, P. Y. (2022). Are hydrologic-hydraulic coupling approaches able to reproduce Alex flash-flood dynamics and impacts on southeastern French headwaters?. In Advances in Hydroinformatics: Models for Complex and Global Water Issues—Practices and Expectations (pp. 419-436). Singapore: Springer Nature Singapore. Link
CEREMA. 2021. RETEX technique ALEX - Inondations des 2 et 3 octobre 2020 - Consensus hydrologique. Rapport établi pour le compte de la DDTM06, version 2 du 14 Sept., 59 p. (In French).
Chochon, R., Martin, N., Lebourg, T., & Vidal, M. (2022). Analysis of extreme precipitation during the mediterranean event associated with the Alex storm in the Alpes-Maritimes: atmospheric mechanisms and resulting rainfall. In Advances in Hydroinformatics: Models for Complex and Global Water Issues—Practices and Expectations (pp. 397-418). Singapore: Springer Nature Singapore. Link
Payrastre, O., Nicolle, P., Bonnifait, L., Brigode, P., Astagneau, P., Baise, A., ... & Sevrez, D. (2022). Tempête Alex du 2 octobre 2020 dans les Alpes-Maritimes: une contribution de la communauté scientifique à l’estimation des débits de pointe des crues. LHB, 2082891. https://doi.org/10.1080/27678490.2022.2082891