1001 Smart Cities

Permanent project revision

Ville en Alerte — Flood Sensor Network and GEMAPI Duty Room

Revision 2026-08-22-evidence-baseline · effective 2026-08-10

Current revision. This is the snapshot used by the live entity page.

unreviewed

Created the first structured Evidence Passport with 19 claims and 5 source dossiers.

sha256:d7a003a91efa85644fd93545dcf29e3e0deef0db280656822944903de9614792
All revisions → Current entity page →

Change set

  • add /evidencePassport — Added claim-level evidence mapping and source dossiers.
  • add /revisionHistory — Established a permanent, hash-addressed baseline revision.
19
of 19 claims mapped
5
source dossiers
2
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-9c9f00f7b33db332 descriptive
the Lez and the Mosson drain a karst catchment that can take a Mediterranean autumn downpour in hours
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The Metropole's own report describes the karst systems of both rivers and the speed of the resulting floods. Its research chapter on groundwater states that “Le climat méditerranéen, avec ses pluies intenses entre de longues périodes sèches, provoque des crues rapides, dont l'ampleur peut être modulée par le karst selon la saturation des sols et de l'aquifère”, and that the karst “peut augmenter le débit maximal pour 60 % des épisodes et contribuer jusqu'à 80 % du volume de crue, avec des montées parfois très rapides”. The December 2025 review names “une saturation des sols et des systèmes karstiques du Lez et de la Mosson”. For the timescale, the report records the September and October 2014 episodes as “300 mm et 250 mm de pluie en quelques heures”.
Caveat
The report ties the fastest recorded downpours to September and October 2014 and to December 2025; it does not single out autumn as the season for these events.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 2 clm-cce5e6f97e7e073d quantitative
runs about 50 water-level and rain sensors, plus cameras and piezometers
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The 2025 activity report describes “un parc conséquent de 50 capteurs” for flood monitoring and, under its 2025 spending lines, “GESTION DU PARC DE CAPTEURS de suivi des crues et de la pluie (pluviomètres) : pose de 6 nouvelles stations et maintenance du parc de 50 capteurs” — so water level and rain. The same report records piezometers installed at Cournonsec and Cantagrils. France Digues describes the monitoring network as “une vingtaine de capteurs mesurant la hauteur d'eau, de capteurs pluviométriques et de caméras implantées sur le terrain”, which is where the cameras come from.
Caveat
Neither source says the cameras or the piezometers are counted inside the park of 50. France Digues, writing in 2022, put the water-level sensors at about twenty, and the Metropole's own English page still states 22 monitoring sensors; the figure of 50 comes from the most recent report.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
  2. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 3 clm-21fa980f02f998da quantitative
feeding a GIS platform called Ville en Alerte that was built by Egis Eau with Predict Services, Ceneau and Synapse between 2016 and 2021
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Egis lists itself as lead contractor for Ville en Alerte with a project calendar of “Avril 2016 – Avril 2021”, a client of “Montpellier Méditerranée Métropole” and a crisis-management tool delivered “sous format SIG”. The Metropole's own crisis engineer, interviewed by Banque des Territoires, names the four firms: “les quatre prestataires qui ont conçu l'outil « Villes en Alerte », à savoir, Predict Services, Egis Eau, la société Ceneau et la société Synapse”. France Digues describes the result as “une cartographie interactive (type SIG)”.
Caveat
The 2016–2021 window is Egis's own contract calendar, not the life of the system. Egis names its partners differently — “Egis, Synapse et Ceneau Predict” — and the Metropole dates the origin of the tool to the 2012 Ecocite project, with the first sensors going in long before that.

Sources carrying this claim

  1. Egis — Ville en alerte, un dispositif pour anticiper et maîtriser le risque inondation
  2. Banque des Territoires (Numérique360) — Gestion des risques : Montpellier se dote d'un système d'alerte innovant pour anticiper les crues
  3. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 4 clm-dc2bf8ec696d49c5 quantitative
completely renewed in 2021
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The Banque des Territoires case study carries a key-dates panel whose 2021 entry reads “Modernisation et remise à neuf totale du parc avec de nouveaux composants et de nouveaux modes de transmission”.
Caveat
The source applies the total renewal to the sensor park — new components and new transmission methods — not to the Ville en Alerte software itself.

Sources carrying this claim

  1. Banque des Territoires (Numérique360) — Gestion des risques : Montpellier se dote d'un système d'alerte innovant pour anticiper les crues
Claim 5 clm-ecfdcc50e2cf35a9 descriptive
When a gauge crosses a pre-set threshold an SMS goes to the GEMAPI duty service, which sends agents to look before relaying anything to mayors, the prefecture and the fire service.
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
France Digues, writing up a presentation of the tool by the Metropole's own crisis engineer, sets out the chain: “si un capteur détecte le franchissement d'un seuil préalablement défini, une alerte sms est déclenchée au sein du service GEMAPI. Des agents sont alors dépêchés sur le terrain pour une première surveillance visuelle et l'information est relayée aux acteurs locaux.” It names the recipients: the tool “sert aussi bien aux maires et aux servcies techniques dont l'ensemble des informations partagées en temps réel sont indispensables à la Préfecture et aux SDIS”. Banque des Territoires describes the same alert differently: the sensor “envoie une alerte SMS sur un certain nombre de numéros de téléphone, dont celui du maire, des équipes techniques, et le nôtre, les gestionnaires” — that is, the mayor receives the message at the same time as the duty service, not after the field check.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 6 clm-32d1b951b644dd36 descriptive
Nothing is actuated automatically
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
France Digues states that the alert level on a protection structure is set by hand: “Pour l'instant le niveau d'alerte est enclenché manuellement sur la base des données collectées par les capteurs et visites de terrain.” The tool is described as supporting the decisions of local actors rather than taking them.
Caveat
The Metropole's own English page lists “real-time management of water regulation basins” and “triggering of safety measures” among the tool's functions, and France Digues writes “for now”, leaving open whether the manual step is permanent.

Sources carrying this claim

  1. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 7 clm-bd2f55a5ef5c5a53 quantitative
470 flood-prone road points across the 31 communes so that closures can be ordered by people
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The 2025 activity report counts “les 470 points submersibles identifiés au niveau des voiries des 31 communes” among the assets whose safety depends on watercourse maintenance, and records that during the December 2025 episode the protective measures taken included “la fermeture de points bas”. France Digues says the platform is where preventive actions are recorded: “la plateforme permet également de renseigner les actions préventives mises en place telles que les coupures de voiries, les déviations, etc.”
Caveat
The report counts the 470 points in its watercourse-management chapter and does not describe them as a layer of the Ville en Alerte platform.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
  2. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 8 clm-d2ff0f1157675035 quantitative
a park of 50 sensors tracking flood formation and propagation in real time at bridges and protection structures
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report's surveillance chapter reads: “La surveillance des crues et des OPCI : un parc conséquent de 50 capteurs permet de suivre en temps réel la formation et la propagation des crues, et le niveau des cours d'eau au droit des points stratégiques du territoire, notamment au niveau des ponts et OPCI.” OPCI are the flood-protection structures the Metropole operates.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 9 clm-a8be7fec8d3340ea quantitative
six new stations added and €130,000 spent on the sensor park in 2025
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Under “LES PRINCIPALES RÉALISATIONS 2025” the report lists: “GESTION DU PARC DE CAPTEURS de suivi des crues et de la pluie (pluviomètres) : pose de 6 nouvelles stations et maintenance du parc de 50 capteurs. Montant : 130 k€”.
Caveat
The 130,000 euros covers both the six new stations and the maintenance of the existing park; the report does not split the two.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 10 clm-79d121f59a02be07 quantitative
€32,000 on maintaining and modernising the Ville en Alerte tool itself, €30,000 on Météo-France and Predict Services subscriptions
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Two of the report's 2025 spending lines: “MODERNISATION ET MAINTENANCE DE L'OUTIL VILLE EN ALERTE : développement de nouvelles fonctionnalités. Montant : 32 k€” and “ABONNEMENTS à Météo France et Prédict Services : Montant : 30 K€”. The same page gives the chapter's total as 0.3 million euros.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 11 clm-f12508c6fd68c463 quantitative
an average of 65 expert hydro-meteorological bulletins issued each year to the 31 communes
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report states that the duty service “assure en moyenne chaque année la diffusion de 65 bulletins de prévision hydrométéorologiques auprès des 31 communes et des services de Montpellier Méditerranée Métropole”, and that these are expert products: “des bulletins hydrométéorologiques expertisés sont transmis aux élus, DGS et services métropolitains”.
Caveat
Sixty-five is the report's own long-run average. The same report records 110 bulletins actually sent in 2025, the year it covers.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 12 clm-e326c6dc0ebb0740 quantitative
and 110 in 2025 itself
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The same activity report that gives the annual average of 65 expert bulletins records 110 issued during 2025 — so the year the entry describes ran well above its own long-run average.
Caveat
The report does not explain the gap between the average and the 2025 count; the December 2025 rainfall episode described in this entry is the obvious candidate but the report does not attribute it.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 13 clm-2603d274c6296366 quantitative
In the week to 23 December 2025 the territory took about 450 mm of rain — more than half its annual total, including 163 mm in 24 hours at Alco on 22 December
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report's review of the December 2025 event reads: “Sur la période du 19 au 23 décembre, le cumul atteint 330 mm, portant le total hebdomadaire à environ 450 mm sur Montpellier, dont 163 mm en 24 heures sur le secteur d'Alco à Montpellier le 22 décembre. En une semaine, plus de 50 % de la pluviométrie annuelle a ainsi été enregistrée, sans phase de ressuyage significative.” The “more than half the annual total” comparison is the report's own, not a calculation made here.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 14 clm-9f4f938828b9bd78 quantitative
the duty room opened at 08:00 that day, low points were closed and evacuations advised
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report states: “l'astreinte sécurité GEMAPI a été activée dès 8h le lundi 22 décembre 2025, avec l'ouverture du Poste de Commandement GEMAPI détaché”, and that “Des mesures de protection des populations et des biens ont été mises en œuvre, telles que la fermeture de points bas, des préconisations d'évacuation et la sécurisation de secteurs sensibles.” The same section describes the room itself: four screens carrying Météo-France, Predict Services, Ville en Alerte and the flood sensors, with a fifth for videoconferencing.
Caveat
The report does not say who ordered the closures or the evacuation advice; the measures are described at the level of the territory, and communal safeguard plans are the mayors' responsibility.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 15 clm-67d8ff31af7dc34c quantitative
damage to watercourses and structures was put at €1M plus €100,000 of debris clearance
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report records: “une phase post-crue a été engagée afin d'évaluer les dégâts estimés à 1M€”, adding that “Les principaux dommages constatés concernent les ouvrages et les cours d'eau”, and separately that plastic macro-waste deposited in the Lez, the Mosson and the Lironde required “des opérations de désembaclément et de nettoyage pour un montant estimé à 100 000 €”.
Caveat
The one million euros is the report's overall post-flood damage estimate; the report says only that the main damage concerned structures and watercourses, not that the whole sum was spent on them.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 16 clm-8672ccbd4962c635 descriptive
a threshold crossing raises an SMS, not a barrier
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
France Digues describes exactly this: when a sensor detects a pre-set threshold being crossed, “une alerte sms est déclenchée au sein du service GEMAPI”, and nothing physical follows from the reading itself — “Pour l'instant le niveau d'alerte est enclenché manuellement sur la base des données collectées par les capteurs et visites de terrain.”
Caveat
France Digues writes “for now” about the manual step, and the Metropole's English page lists real-time management of water regulation basins among the tool's functions.

Sources carrying this claim

  1. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 17 clm-021410c4ff89226c descriptive
The Métropole sends an agent to look at the river before anything is relayed
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
France Digues: “Des agents sont alors dépêchés sur le terrain pour une première surveillance visuelle et l'information est relayée aux acteurs locaux” — the field check comes first, the relay second. Banque des Territoires describes the same SMS as going straight to a list of numbers “dont celui du maire, des équipes techniques, et le nôtre, les gestionnaires”, which puts the mayor on the first message rather than after the visual check.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier
Claim 18 clm-b64fc31bbd617f65 descriptive
its own report notes that piezometers had to be added at Cournonsec and Cantagrils just to tell when the underground network is saturated
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The report's research chapter on the contribution of groundwater to Mosson floods states: “Pour suivre la saturation des sous-bassins, des piézomètres ont été installés à Cournonsec (Coulazou) et à Cantagrils (Mosson amont), permettant d'identifier les seuils de débordement et d'activer les réseaux karstiques.” The same chapter finds the karst can raise peak flow in 60 per cent of episodes and contribute up to 80 per cent of flood volume.
Caveat
The report presents the piezometers as part of a research study into how groundwater feeds the Mosson, and does not say they were added because the surface gauges were misleading.

Sources carrying this claim

  1. Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF)
Claim 19 clm-cd75907e1ceb43fe quantitative
the first two gauges went in for the 1998 World Cup, because the stadium had been built in a flood zone
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Nils Souteyrand, the Metropole's own forecasting and crisis-management engineer, tells Banque des Territoires: “Historiquement, l'installation des deux premiers capteurs s'est faite à l'occasion de la Coupe du monde de 1998 ! Montpellier était une ville qui accueillait des matchs de foot, notamment dans le stade de la Mosson, qui a été construit en pleine zone inondable.” The article's key-dates panel repeats it: “1998 — Coupe du Monde de Foot et installation des premiers capteurs sur le territoire de Montpellier.”
Caveat
This is a recollection given in a 2024 interview by a serving Metropole engineer; no contemporaneous document is offered for the 1998 installation or for the reason behind it.

Sources carrying this claim

  1. Banque des Territoires (Numérique360) — Gestion des risques : Montpellier se dote d'un système d'alerte innovant pour anticiper les crues

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-22-evidence-baseline effective 2026-08-10 · created 2026-08-22

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:d7a003a91efa85644fd93545dcf29e3e0deef0db280656822944903de9614792
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
19
of 19 claims mapped
5
source dossiers
2
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Montpellier Méditerranée Métropole — service GEMAPI (platform built by Egis Eau with Predict Services, Ceneau and Synapse)
Actor types
city-government
Funding model
Not recorded
Funding description
Montpellier Méditerranée Métropole (GEMAPI levy); the 2012 expansion came through the national Écocité programme
Cost
≈€480,000-510,000 for the 2016-2021 build; €130,000/year sensor park and €32,000/year platform maintenance in 2025
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

5 source dossiers

Montpellier Méditerranée Métropole — La GEMAPI, rapport d'activité 2025 (PDF) montpellier.fr · 12 linked claims

Open original source ↗

Stable source ID
src-c78ec2a66c7c3e4b
Publisher
Name not classified · montpellier.fr
Type / language
pdf · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-10
Dossier created
2026-08-22
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The operator's own annual report, published April 2026. Source for the 50-sensor park, the €130k/€32k/€30k/€20k budget lines, the 65 bulletins a year, the 470 submersible road points, the four-screen duty room showing Météo-France, Predict Services, Ville en Alerte and the flood sensors side by side, and the full December 2025 event narrative (450 mm in a week, 163 mm/24h at Alco, PC opened 08:00 on 22 December, €1M damage, €100k debris clearance).

Descriptive only — not page/paragraph exact
Claims linked
Egis — Ville en alerte, un dispositif pour anticiper et maîtriser le risque inondation egis-group.com · 1 linked claim

Open original source ↗

Stable source ID
src-cb4132173430057f
Publisher
Name not classified · egis-group.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-10
Dossier created
2026-08-22
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The contractor's project page: client Montpellier Méditerranée Métropole, dates April 2016 - April 2021, 37 water-level sensors plus rain gauges and cameras at the time of delivery, €510,000, and the three components (sensor network, historical flood scenario database, collaborative crisis-management software). This is the datable build of the system and the basis for yearStart 2016.

Descriptive only — not page/paragraph exact
Claims linked
Banque des Territoires (Numérique360) — Gestion des risques : Montpellier se dote d'un système d'alerte innovant pour anticiper les crues numerique360.banquedesterritoires.fr · 3 linked claims

Open original source ↗

Stable source ID
src-a3e54da5e79590af
Publisher
Name not classified · numerique360.banquedesterritoires.fr
Type / language
web-page · language not classified
Published
2024-10-22
Updated
2026-07-20
Source last checked
No source-level check date
Record last verified
2026-08-10
Dossier created
2026-08-22
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

October 2024 case study. Gives the chronology (first two sensors installed for the 1998 World Cup because the stadium sits in a flood zone; 2012 start of the Écocité project; total renewal of the park in 2021), 40 stations over ~200 km of watercourses heading for 45, €10,000-15,000 per station and ~€480,000 total, and the four suppliers.

Descriptive only — not page/paragraph exact
Claims linked
France Digues — Ville en alerte, un système de surveillance et de gestion de crue sur la Métropole de Montpellier france-digues.fr · 7 linked claims

Open original source ↗

Stable source ID
src-c319613dee5ac7f0
Publisher
Name not classified · france-digues.fr
Type / language
web-page · language not classified
Published
2022-03-22
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-10
Dossier created
2026-08-22
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Levee-operators' association write-up. Confirms the alert chain in detail: threshold crossing triggers an SMS inside the GEMAPI service, agents are dispatched for visual checks, and only then is information relayed to mayors, technical services, the prefect and the SDIS. Also the real-time metrology view of dykes, retention basins and the Lac des Garrigues dam.

Descriptive only — not page/paragraph exact
Claims linked
Montpellier Méditerranée Métropole — Aquatic environments and floods montpellier.fr · background

Open original source ↗

Stable source ID
src-31f6e2aec4fe17a7
Publisher
Name not classified · montpellier.fr
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-10
Dossier created
2026-08-22
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The Métropole's own description of the tool — forecasting, sensor monitoring, event simulation, real-time management of retention basins, triggering of safety measures and public alerting — and the IRISES trophy won at the Forum sur les risques majeurs in February 2022. States 22 monitoring sensors, fewer than the 2025 activity report's 50; the higher operator figure from the more recent report is the one used here.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Known limits of this passport
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.