Risques d’inondation : pourquoi les diagnostics actuels ne suffisent plus à protéger vos entreprises et maisons ?

Flood risks: why are current diagnostics no longer sufficient to protect your businesses and homes?

📆 Since 2003, Property owners must provide their buyers and tenants with a report on the main dangerous phenomena (pollution, flooding, earthquakes, etc.) to which their property is exposed. Purchaser and Tenant Information (PTI) is valuable information for making a decision to purchase, install, open a business, set up a workshop, store machines or products, etc.

🔢 A diagnosis of exposure to natural risks is mandatory before any transaction , and the minimum information that must be included is defined by article R. 125-24 of the Environmental Code. It is not necessary to use an approved professional to make a diagnosis. It is sufficient to indicate whether the building is located in an area affected by one or more natural risk prevention plans (PPRN), to specify whether the PPRN is prescribed, anticipated, approved, or approved and under review[1], and finally to list the natural risks concerned.

🌍 To find out the updated status of the PPRN and therefore the vulnerability of the property, the owner is referred to the Géorisques website ( www.errial.georisques.gouv.fr ). Géorisques is produced in partnership between the Ministry of Ecological Transition and Territorial Cohesion and BRGM. BRGM is the French public institution for Earth science applications. By entering the address on the site, the platform provides a diagnosis of technological risks (industrial installations, soil pollution, pipelines for transporting hazardous materials, etc.) and natural risks (flooding, ground movements, earthquakes, shrinkage and swelling of clays, radon).

❓ Is this enough? Let’s take flood risk for example. Flood risk is the leading natural risk in France. Floods affect more and more businesses and individuals. Nearly 10 million jobs in France, or about a third of jobs, are located in risk areas, in other words in flood zones, generally covered by a PPRN. But floods are not just the result of rising water tables or river floods. In fact, The vast majority of floods are caused by sudden, intense rainfall or violent storms which cause runoff and accumulations of water that cannot be drained away by pipes. In Ile-de-France, for example, 92% of municipalities were subject to at least one Cat-Nat (Natural Disaster [2]) order for flooding phenomena between 1982 and 2021, but 88% were due to runoff phenomena [3]. In most cases, these floods did not occur in a flood zone, in other words in an area affected by a PPRN. Finally, let us note that we all indirectly finance the Cat-Nat fund and that the latter is intended to grow in order to deal with the effects of climate change ("The scheme is financed by an additional contribution based on the premium of insurance contracts, the "CatNat surcharge", the rate of which will increase from 12% to 20% on 1 January 2025"). [4] Excessive use of the Cat-Nat regime induced by the use of obsolete and unsuitable climatological indicators has the direct consequence of a loss of purchasing power for individuals, businesses and communities.

🔎 In practice, a company or a trader who consults Géorisques to find out if they are affected by flood risk will obtain a response in accordance with the meaning of the environmental code, but not in the sense of the risk manager who must preserve the work tool and the safety of property and people . This is all the more critical as rainy episodes causing significant runoff are increasing. Many regions have been affected this year, such as Lorraine for example.

✒️ This is the same information that is transmitted to future buyers of a residence when they sign at the notary: among the large number of documents reviewed, there is this same statement of risks which should be a tool to help with the purchasing decision. Well informed of the risks involved, the future buyer must be able to make an informed decision with full knowledge of the state of the perils to which his future property will be exposed. Being poorly informed means heading towards possible disappointments with more or less serious consequences.

❗To illustrate our point, here is a real example of a restaurant for which the diagnosis Géorisques does not indicate any flood risk at the address indicated (Fig. 1). However, the restaurant was flooded following a storm, much to the dismay and surprise of its owner (Fig. 2).

Fig 1. Extract from the Georisk Diagnosis

Left image credit Google Maps | Right image credit Le Républicain Lorrain

Fig 2. Before / After an intense storm episode.

☔The risk report indicated to the owner that his restaurant was not prone to flooding, so he did nothing to prevent the risk and minimize the damage (damaged equipment, loss of business, partial unemployment).

🎯To anticipate these risks, Tardigrade AI's Climate Performance Diagnostic (CPD) provides a complete diagnosis of climate vulnerability that informs the tenant or owner of a site or building about its exposure to around ten climate hazards, including flooding.

⛈️The DPC actually confirms that the restaurant in question is not exposed to river flooding, but highlights significant exposure to rain flooding. The DPC indicates a risk of 80 cm of water in the restaurant in 2024 with a probability of occurring of 2% within 20 years, and an even higher water level by 2050 based on climate projection models based on IPCC scenarios (Fig. 3) .

Excerpt from the DPC Tardigrade AI

Fig 3. Extract from the Tardigrade AI Climate Performance Diagnostic

🔬 The climate is changing, and so is the way we measure and anticipate flood risks. Based on science and technology, The DPC Tardigrade AI provides the geolocated water height to which a property is exposed. This water height is obtained from a digital twin of the terrain which reproduces the building concerned and its environment, integrating the surrounding constructions, the nature of the soil, the slopes, the height of the buildings, etc., on which the historical data and projections of precipitation are applied.

🔢 A static diagnosis , based on the PPRN, which does not script or project climate knowledge is certainly compliant, but does not allow adaptation or prevention actions to be taken which should have been taken or led to inappropriate responses.

💡When we know, we can anticipate , not store products or key documents in an exposed area, raise equipment and machines, dining rooms or offices, provide sandbags or removable devices (cofferdams), preposition pumps, etc. When we know the information before setting up, we can also simply choose to set up elsewhere. A business leader cannot stop the rain from falling, but today he has a tool to preserve his work tool and the jobs of his employees as much as possible: the DPC Tardigrade AI.

Would you like to obtain a diagnosis for your business? Contact us on contact@tardigrade-ai.com

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