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average of 0.25 metre additional subsidence in this century, up to 1.0 metre in
some locations.
The Dutch approach
The method of flood defence that the inhabitants of the Netherlands have
developed and applied - with varying degrees of success - throughout the centuries
is dike building. Ever since the eleventh century, when the earliest primitive dikes
and embankments were built, the task of keeping the hungry sea and rivers at arm's
length has been a matter of dogged perseverance and trial and error. Since then the
main outlines of the Dutch coast have changed very little. The Dutch success
resulted in 1113 in a contract of the King-Bishop Frederik I of Bremen with a
group of Dutchmen under leadership of Priest Heinricus to reclaim Northwest
German lowlands in a Dutch style. Dutch engineers invited by the Japanese
Emperor (Ming dynasty) assisted in the regulation of water management problems
and land reclamation (Johannes de Rijke). As military history has demonstrated,
the shorter the lines, the stronger the defences. The first real major improvement in
the Dutch coastal defences came in 1932, when the Afsluitdijk (Zuyderzee Barrier
Dam) was built, linking the coasts of the provinces of North Holland and Friesland.
This dike shortened the 1900-km coastline to 1300 km. It was a flood disaster in
1916 that gave the final impetus to the decision to link up the two coasts. After
1945 new plans were made to improve the country's defences against the sea and
major rivers. But governments learn slowly, and it took another disaster to give the
impetus to carry the Delta plan into the execution stage.
Figure 17.3 Maeslandt Barrier; the gates are as long as the Eiffel tower is high
The Delta-sea project
In February 1953 the dikes of the delta area in the southwest Netherlands were
breached during a severe storm. 1835 people lost their lives and the material
damage was enormous. The following Delta Act in 1956 provided for reinforcing
the dikes and completely damming off the largest estuaries. Only the Western
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