Valencia: the last straw?
On 29 October 2024, the Valencia metropolitan area in Spain was hit by yet another flood, caused by a meteorological phenomenon. The first messages, and many more afterwards, blamed it on climate change and fossil fuels. Yet some thirty floods have been recorded since 1238, the most recent in 1957, 1982,1987 and 1996, already without global warming. So?
What does the IPCC say about floods?
“In summary, it is very likely that floods larger than those recorded since the 20th century occurred during the past 500 years in northern and central Europe, the western Mediterranean region and eastern Asia. There is, however, medium confidence that in the Near East, India and central North America, modern large floods are comparable to or surpass historical floods in magnitude and/or frequency. (AR5, 5.5.5, p. 425).In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale. (AR5, 2.6.2.2, p. 214).”
Valencia and floods: an infernal couple
Since flood records began in 1238, 30 floods of the Turia river have struck the city and its province, the most recent in 1957, 1982, 1987 and 1996. Their number and recurrence make them an essential element in the functioning of the city, a permanent danger, and they ought to guide local policies.
The Gran Riada South Plan
In 1958, after the 1957 floods, the city, the autonomous community and the Spanish State launched and carried out the Gran Riada South Plan. This plan was chosen rather than the solutions to the North or in the centre. This. major river diversion project consisted of building a canal reaching the sea and retention basins, in a market-gardening area, the Valencian huerta, uninhabited at the time. A relevant project in terms of flood control, since it made it possible to turn the agricultural plain into a vast floodplain.
This project removed the river’s course through the city and made it possible to undertake major works to embellish the city and restructure the port, the largest in terms of freight.
The article by Jean Sermet[1] states that from then on “the development of the city towards the agricultural plain of the Huerta (the name of this southern part of the city) is prohibited and no building permits will be granted”.
Map showing the location of the South Zone
Source: Michelin map
Comment: the Turia diversion canal appears between Manises and Pinedo.
An administration whose competence is open to question
The Valencian Community, the 3rd largest in Spain, has 2,400,000 inhabitants and the city, also the 3rd largest, 800,000 inhabitants, which is very significant.
Map of the Valencian Community
In Spain, the regional administration of the autonomous community is responsible for safety and for alerts in the event of a disaster. Various daily press articles state that President Mazon hesitated for 2 hours before triggering the alert at 8.10 pm, thereby trapping many people returning from work on the motorways. He thought long and hard before asking the emergency services under the State administration, the Military Emergencies Unit (which he had previously criticised as too costly) to intervene. The central State administration itself did not take the decision to raise the alert level or to declare a state of emergency.
This slowness is very probably largely responsible for the 230 deaths and the chaos.
“Libération[2] suggests that dozens of deaths could have been avoided if the alert had been given by the authorities, telling residents that they must on no account take to the roads, go down into car parks or stay on ground floors; many of the victims would still be alive, most of them having drowned in their cars swept away by the force of the waters. ‘We know that an alert issued twenty-four hours before the arrival of a storm or a heatwave can reduce the resulting damage by 30%,’ Celeste Saulo, Secretary-General of the World Meteorological Organization, told Libération[3].”
4 November 2024 / Association des climato‑réalistes
Flood figures
Source: Copernicus
Comment: the positioning of the deaths around Valencia is very approximate.
A city centre spared and southern districts badly hit
The flood impact map published online by Eduscol speaks volumes.
While this area is the epicentre of the floods, which also came from two other rivers further south, the Jucar and the Magro, dry during the summer, , it did indeed spare the centre of Valencia.
In the south, on the other hand, the Huerta plain is the epicentre of this flood.
This is therefore a different event from the Turia floods, for which the canal and the floodplain were put in place. Fate?
Map of flooded areas
The patch in the right-hand corner of the map corresponds to the city of Valencia
The brown tongue corresponding to the flooded area represents the Huerta plain
Source: Eduscol ENS Lyon
Priority urbanisation in a prohibited zone
“According to L’Express[4], one million homes are located in flood-prone areas, more than a quarter of them in the province of Valencia alone. The diversion of the course of the Turia river, following the great flood of 1957, made it possible to protect the centre of Valencia. The flip side was that the flood flows shifted to the surrounding suburbs, in Chiva, Picanya, Paiporta.”
4 November 2024 / Association des climato‑réalistes
We thus discover that the agricultural plain of the Huerta, set aside for flood expansion and closed to urbanisation as early as 1958 …. continued to be urbanised by the local authorities.
Neither the temperature of the Mediterranean water nor the eruption of the Tonga volcano is responsible.
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Description of the cold drop phenomenon that hit Spain |
Conclusion
The local administrations of Valencia and its autonomous community were responsible, on several occasions, for decisions that raise questions. By acting unprofessionally at the time of the flood of 29 October 2024, which the president of the autonomous community acknowledged at a press conference. Perhaps the results of political conflicts, which the flood should have silenced.
On the other hand, the floods of the Jucar and the Magro created an unprecedented situation that the South Plan did not address.
An event that revealed administrative drift, soil sealing and the construction of numerous buildings on the Huerta plain, where building is prohibited and which has been set aside for flood expansion since 1958.
The climate and the cold drop completely masked this drift, which developed construction in a zone prohibited since 1958, almost uninhabited at the time, a flood expansion zone.
They concealed this massive, illegal urbanisation and the responsibility of elected officials and town planners.
Mr Dominique MUSSLIN
Architect, graduate of the Lille school of architecture
Town planner, graduate of the Brest institute of Geo-architecture
Lecturer at the Universities of Montpellier and Strasbourg
Sources
- La défense de Valence contre les crues du Turio - Jean Sermet - Revue géographique des pyrénées et du sud ouest européen, 1958, pages 293‑295
- Inondation dévastatrice à Valence - 13.11.2024 - Clara Loïzzo, Alex Prados Linde - Eduscol ENS Lyon
- Bulletin Meteo France -30/11/2024
- Bulletin des climato‑réalistes - 4/11/2024
Illustration by BAM!
[1] Revue géographique des Pyrénées et du Sud‑Ouest, tome 29, fascicule 3, 1958. - Persée
[2] Inondations dans l’est de l’Espagne : les morts évitables – Libération
[3] Tempêtes, ouragans, pluies torrentielles : “Ce sont des rappels tragiques de notre nouvelle réalité climatique” – Libération
[4] Inondations en Espagne : quand l’aveuglement politique conduit à la catastrophe – L’Express
