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Protecting people, property, and industry
The Maeslant (Maeslantkering)
storm surge barrier

The Maeslant (Maeslantkering) storm surge barrier is located on the Nieuwe Waterweg; a primary access point to the Port of Rotterdam in the Netherlands. It is controlled by a supercomputer and is closed once every year in September to test its operability prior to the arrival of the storm season which begins in October and goes through February. This gate is part of the "Delta Works" and is one of the largest moving structures on Earth. Its supporting structure and the gate itself measures longer than the Eifel Tower in France.

These gates actually float!
Each of its two sections has 15 watertight compartments that keep it afloat. When being deployed each gate section is moved on top of the water into the channel to a position that, when closed, is one meter from the other. The one meter opening is to ensure that when there is rough water that the two sections do not hit and damage each other.

Once the gate's sections are in place, the watertight compartments are opened -- starting at the shoreline -- until the structure sinks and rests on the bottom of the channel. Once the storm has passed the process is reversed by pumping air into the watertight compartments -- forcing the water out -- and raising the structure back into its floating position. It is then brought back into its open (storage) position.
The Maeslant storm surge gate in the process of closing, September 2019

Click on image (above) to see a video of the gate closing

The red dots on the image below indicate where
the images above and left were taken from.
Image of gate from the seaword sideThe gates almost closed Birdseye view of the Maeslant storm surge barrier
Basin where the gate is stored when in the open position
After seeing this gate in operation, I am a big fan of what the U.S. Army
Corps of Engineers is proposing -- having two smaller versions used at the
entrance to the Houston Ship Channel.

See diagram below
Proposed gates for the Houston Ship Channel