Amsterdam city center narrowly avoided a massive flood due to a tech failure that opened the seven sluice gates in IJmuiden that normally keep the North Sea water out of the Netherlands. For around two hours on November 2, billions of liters of North Sea water flowed toward Amsterdam unnoticed. Only an alert employee of the Amstel, Gooi, and Vecht water board closing the 14 locks to the city center prevented a disaster, NH Nieuws reports based on a Rijkswaterstaat report.
Storm Ciarán battered the Noord-Holland coast with strong winds and high water levels that night, but ships still passed through the locks at IJmuiden. At 3:52 a.m. on November 2, the control system of the sluice gates in IJmuiden switched to manual operation, and all seven gates were left fully open. The cause of this glitch is still unknown, but it nearly caused a disaster because, from that moment on, seawater flowed freely into the North Sea Canal toward Amsterdam.
Almost two hours later, at 5:45 a.m., Rijkswaterstaat operating staff noticed that the water level in the North Sea Canal was about 20 centimeters higher than normal. They also noticed that the sluice gates could only be operated manually, but they did not connect the two and attributed the high water level to Storm Ciarán. It was only when an alert employee of the Amstel, Gooi, and Vechtstreek water board pointed out that the open sluice gates were causing the high water levels that action was taken.