Brussels prepares emergency plan for large-scale flooding

The Brussels region is developing a plan to tackle large-scale flooding, which is expected to become more frequent as a result of climate change.

Flooding is one of the main natural risks for Brussels, which is why the region already has done significant work in prevention and protection, especially when it comes to building stormwater basins in recent years.

“But what was still lacking was a plan for how we would react when all these measures were no longer sufficient and we really reached a crisis point,” said Michael Antoine, an engineer in the water department of Brussels Environment.

“The aim of the crisis plan is really to be able to cope, to be resilient and therefore to anticipate a whole series of actions that can reduce the damage to property and people in different contexts.

"It's not about panicking, but it's above all about developing this risk culture and having the right reflexes that can also be used for smaller-scale flood crises."

The new emergency plan is based on rainfall levels observed in the country at large and revolves around four main risk scenarios: extreme sewer backup in basements and on road surfaces, high water levels in rivers overflowing their banks, obstruction of the central channel of the Senne river, and extreme water run-off via roads, also known as flash flooding.

The fatal floods in Wallonia in summer 2021 were also considered.

“It's rare, but these episodes are realistic and indeed, climate change is going to make this type of event more frequent,” said Antoine.

“We can see that thunderstorms are becoming increasingly intense, with little mobility and therefore also generating large quantities of water.”

Up to a third of the population - about 430,000 inhabitants - of Brussels could potentially be affected by large-scale flooding and a quarter of the region's buildings are located in flood-prone or partially flood-prone areas. In Brussels city centre, a major flood could potentially affect 8,000 buildings.

While the plan lists sensitive areas, it is and above all a tool for coordinating the fire and rescue services.

“The most important thing is coordination,” said Sophie Lavaux, in charge of crisis management in Brussels.

“In other words, the various people in charge, not just the authorities, but also the fire brigade and the police, sit down around the table to take the different measures depending on the situation, but also on the data and elements that will be available to us.”

A series of measures are already listed in the plan in the event of a crisis, including evacuation procedures.

“As an authority, we can ask the population to evacuate vertically: in other words, if there is a major flood, what we ask everyone to do is to climb as high as possible and get to safety,” Lavaux said.

“Obviously, this means listening to the requests and instructions of the authorities, not taking your car and not putting yourself in danger. And we will be able to take other measures, such as banning certain major events, closing parks, closing certain tunnels.”