Reclamation of the Zuiderzee

Abstract

On a voyage of exploration northwards from the Rhine in the year a.D. 9 a Roman general discovered a large lake which he named ‘Flevo Lacus’. It was roughly triangular in shape, probably no more than 250 square miles in extent, and at least 40 miles inland. During the ten succeeding centuries the North Sea gouged great gaps in the northern coastal dunes, swallowed the Flevo Lacus and swept farther and farther inland. By 1450 the Waddenzee and Zuiderzee covered an area of about ten times the size of the original Flevo Lacus, and further penetration was held in check only by building and maintaining massive dikes along the 186 miles of coastline: an enormous effort for human muscle-power wielding only shovels.¹