Where should all the rain that still falls in the Aa and Maas water board area go?

The telephone of area manager Gijs Kerkhof (38) rings. The sensor in the pumping station indicates a malfunction, time to take action. Due to the high water levels in recent days, all kinds of things float with the water and the pumping stations around Den Bosch can become clogged more quickly. The pumping stations ensure that the water level in the area remains manageable and that the water does not flow into Den Bosch and the surrounding towns and villages.

In recent days, the Aa en Maas water board, which manages the water flows in the area between Brabant and Limburg: from Deurne, Helmond, Erp and Veghel, to Den Bosch, has been very busy. Since the end of summer it has rained so much that the soil is completely saturated with water. The measured precipitation has never been this high since measurements began in 1906.

Every drop of rain that still falls has to go somewhere, because it can no longer sink into the ground. Gijs and his colleagues check the measuring points along the Aa river every day. At the bridge at Berlicum, just outside Den Bosch, the Aa flows into the full width of the stream valley.

Normally the water flows under the bridge here at about 5,000 liters per second, now it is 30,000 liters per second. The water level is one meter higher than normal, a boat can no longer pass under the bridge, if the skipper wanted to on the swirling water in the pouring rain.

‘What if scenario’

The protocols have been in place for this ‘what if scenario’ for years. The big question is how much rain will fall. Things will be exciting in the coming days, right around Christmas. Should the storage areas in the meadows be used as a basin to ‘buffer’ the rainwater? It would be the first time, but they are ready for it here and the areas are designed for it.

Gijs Kerkhof’s car comes to a stop on the bumpy road just in front of the meadow where the pumping station is located. Sopping through the swampy meadow with a rake under his arm, Gijs explains why the pumping stations are so important. “Without the pumping stations, the water from the Aa and Maas rivers cannot be properly regulated. Compare it to a clogged shower drain. If you don’t empty it in time, everything will flood too. It’s that simple”.

In the grid of the green pumping station, the problem is visible just above the swirling water edge. The muck is piled up against the grid through which the water flows. Gijs screws together the meter-long rake and scoops the muck out of the water. Just visible behind the bare winter trees, on the edge of the meadow, is a new residential area in the village of Vorstenbosch. “If we don’t do this now, those houses there will soon be flooded.”

Back in the car, Gijs is unraveling his long rake again when the next phone call comes. The municipality’s control room asks about the state of affairs. “It depends on the rain,” says Gijs. “We can’t stop them.” Everyone is alert during Christmas dinner on Monday and keeps their phones on the table.

Along the way, Gijs points out a flooded cycle path and a clogged water canal along the side of the road. “The pipe is clogged and needs to be flushed out. But that is a task for the municipality, we will discuss this immediately.”

Scaled up to level 1

Jeroen Haan is dike manager of the De Stichtse Rijnlanden water board (which includes 14 municipalities in the province of Utrecht and a small part of South Holland). Haan is also director of Water Safety at the Union of Water Boards. He plays a leading role in daily conversations about water safety.

What is the current state of affairs?

“We have been scaled up from level 0 to level 1 for two weeks now. The emergency scale runs from level 0 to level 5, with 5 being a national disaster.”

What happens now?

“Scale 1 means that the dike guards carry out daily inspections. They look to see if there are any cracks or damage through which the water is seeping.”

Is this worrying?

“We are alert but not yet worried. The water boards and dike authorities communicate with each other daily about the water levels. It is not yet a threat to water safety. We can still drain these peaks of water.”

How come?

“We are dealing with two waves of water in a short period of time. It is a combination of high river discharge, high sea levels and storm Pia. We are now preparing for a second wave with high discharge over the Rhine, which we expect on December 28 and 29. These are both because a lot of rainwater falls in the Rhine and Meuse river basin in combination with meltwater from the Alps.”

Also read
The limits of the Dutch water system have been reached

Is this exceptional?

“It is high water season, we have seen this coming in the weather forecasts for a few weeks. But now there is suddenly quite a lot of rain. It is one of the wettest years on record.”

What is happening in the country, which points are vulnerable now?

“The water level is now at 13.5 meters, with an expected rise to approximately 14.5 meters above NAP. This was even higher, but the expected rise in water has subsided slightly in recent days.

At Lopik we packed the dike last Thursday with a whole team of volunteers. That is, extra cloths were placed to strengthen the dike. We also do this so that we don’t have to do this during the holidays.

In Overijssel, the Vecht is in danger of filling up and could overflow its banks. Sandbags have also been placed against the dike in Limburg.

All 12 of the 21 water boards located along the rivers, especially the Rhine, are busy absorbing the oncoming wave. Yesterday the water board placed beams at openings in the dike at Delfzijl. All six Rijkswaterstaat storm surge barriers have closed, preventing water from the sea from flowing into the rivers. But then the rivers cannot drain freely into the sea. For the first time in 20 years, the Maeslantkering near Rotterdam (part of the Delta Works, ed.) has closed automatically. This is special.”

Why?

“The thing has been there for twenty years now and has never closed automatically before. We will now have to deal with extreme weather more often. The water discharge in the rivers will occur more in peaks, with both high water and low water during drought. The sea level will rise slowly. The stormwater barriers will then close more often. In addition, the water boards are busy thinking differently about discharging water into the rivers. For example, by installing additional pumps or temporarily storing the water.

Our emergency situations, protocols and systems are based on existing standards that suit the current situation. We will have to step up our game to cope with the weather extremes as predicted by the KNMI and the IPCC (the UN climate panel).”

To share





Email the editor