The Limburg flood disaster (2021): 5 lessons on flooding

What happened

On 13 and 14 July 2021, more than 150 millimetres of rain fell in parts of South Limburg, and locally as much as around 90 millimetres in two hours. The water rose at breakneck speed via the tributary streams such as the Geul, the Gulp and the Geleenbeek in the south, and via the Roer in North Limburg.

In Venlo and the surrounding towns of Baarlo and Kessel, more than 10,000 people were evacuated; evacuations also followed in places including Stein, Sittard-Geleen, Echt-Susteren, Roermond and Roerdalen. From 15 July, an emergency ordinance with compulsory evacuation was in force. The damage was estimated at several hundred million euros. Research (including by Deltares) showed that this was a situation that had not been anticipated in this way, and that such heavy downpours will occur more often as a result of climate change.

Lesson 1: Warn early, even amid uncertainty

When water rises quickly, the time between 'it looks manageable' and 'we have to evacuate' is sometimes only a few hours. So do not wait for complete certainty. Warn early, explain that things can change quickly and tell people what they can already do now.

Use several channels at once: NL-Alert, the water authority's and municipalities' own channels, and the regional broadcaster. An early, honest warning saves belongings and sometimes lives, even if it turns out afterwards that things only just went well.

Lesson 2: Make evacuation information concrete

An evacuation raises many practical questions. Answer them as concretely as possible, both in advance and during the crisis.

• Who does the evacuation apply to, and from exactly when?
• Where can people go, and what should they bring (medicines, pets, documents)?
• How can people who cannot leave on their own get help?
• Where can people find the latest status and when may they return?

Lesson 3: Plans help, but reality differs

An important lesson from 2021 was that the water rose in a way that was not set out as such in the operational plans. Small streams caused major problems. Plans are indispensable, but you must be able to improvise when the situation differs.

That calls for a team that quickly forms a shared picture, dares to make decisions with incomplete information and scales up flexibly. So practise not only the standard scenario but, above all, the unexpected.

Lesson 4: Work as a chain with a shared picture

A flood affects the water authority, the safety region, municipalities, Rijkswaterstaat, emergency services and sometimes neighbouring countries all at once. All these parties must have the same picture of water levels, threatened areas and decisions taken at lightning speed.

Agree in advance how you scale up (GRIP), who communicates about what and how you share information. A shared crisis picture prevents parties from working at cross purposes or residents receiving contradictory information.

Lesson 5: Think about the aftermath and the reporting obligations

When the water recedes, a long aftermath begins: damage, recovery, health (contaminated water) and psychosocial aftercare for those affected. Set up that aftermath deliberately and keep communication going, even once the acute crisis is over.

Drinking-water and water-management organisations are critical entities under the Critical Entities Resilience Act (CER), which specifically concerns all-hazards resilience, such as natural disasters. A significant disruption must be reported within 24 hours. During and after the crisis, record which decisions and reports were made, also with a view to the evaluation.

How CrisisRadar helps

CrisisRadar brings the water authority, the safety region, municipalities and Rijkswaterstaat together in a shared crisis picture. You record facts and water levels with their source, draft a warning and evacuation information within minutes, reach vulnerable residents in a targeted way and publish the current status on your own page. Afterwards, the platform provides an evaluation report for the aftermath.

Would you like to see how an acute flood unfolds step by step in the platform? Then take a look at the accompanying practice scenario.

Stappenplan

Veelgestelde vragen

What caused the flood disaster in Limburg in 2021?

Extreme rainfall on 13 and 14 July 2021, with more than 150 millimetres locally, caused streams such as the Geul, Gulp and Geleenbeek and the river Roer to burst their banks at breakneck speed. More than 10,000 people were evacuated.

Why were the plans not adequate?

The water rose via small streams in a way that was not set out in the operational plans. The lesson is that plans are indispensable, but that a crisis team must also be able to improvise when reality differs. Research also indicates that such downpours occur more often as a result of climate change.

What matters in the aftermath of a flood?

After the acute phase comes a long aftermath: dealing with damage, recovery, health issues from contaminated water and psychosocial aftercare. Set up that aftermath deliberately and keep communication going. Critical water and government organisations record decisions and reports, also for the evaluation.