The barrier consists of two vertical lift gates, and in length. The gates have a height of above
NAP when closed. The
water level at this location can become higher, but in order to prevent flooding of the
Europoort-area the gates were designed to allow the water to overtop the gates in extreme situations. The amount of water would be too small to cause any problems in the protected area but it does limit the surgelevel in the unprotected areas. In the raised position the bottom of the gates is at above NAP, slightly higher than the
Hartelbrug (
nl) next to the barrier. The barrier is equipped with a construction to fend off floating debris, which could damage the gates. The Hartelkering was constructed at the same time as the
Maeslantkering as part of the
Europoortkering, a system of
levees in addition to the two flood barriers. The barrier was built with the expectation to close once per five to ten years. The decision-making algorithm that sequences storm surge-triggered events in the Maeslantkering is run entirely by computer. ==8 November 2007 storm==