English: The design of the Afsluitdijk was based on calculations by the Staatscommissie Lorentz (SCL - English: Lorentz State Commission) had carried out for the very high storm surge of December 22-23, 1894. In the North Sea, a level had been reached that was considered the highest of the past century. The flow to the basin of the Zuiderzee was very strong, and in connection with this, the storm surge levels in the Wadden Sea were relatively low. If the Zuiderzee had already been closed off during that storm, the water in the Wadden Sea would have risen much higher.

This graph shows the results from the SCL design works for a number of locations, the level reached in 1894 (Z), the calculated increase (Δ), the calculated maximum with the closed-off Zuiderzee (A) and the predicted increase in wave run-up indicated by the SCL due to the greater water depth in front of the dike (ΔG). All values are in centimetres above Normaal Amsterdams Piel (NAP - Amsterdam Ordnance Datum).

Data from Thijsse (1972), who based his figures on the SCL report, table 42