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that rubbish would accumulate in
them.’
Wanted: concrete manufacturer
Hans Hill went looking for a concrete
manufacturer. ‘It was still difficult to
find a good factory that was prepared
to take on a new block.’ It was only
when Martens Beton agreed to make his
block that he had something to show
customers. And then things went fast.
After tests in the old Delta Flume at
Deltares and a pilot project in the
Stavenissepolder, it was possible to
perfect the Hill Block. ‘Normally, it is
not the force of the waves that degrades
dike revetments; the problem is the
suction forces when water gets into the
hollow spaces between the blocks. If the
openings are too small, the water rips
the blocks off the dike.’
Rijkswaterstaat, the Dutch govern-
ment agency that is responsible for the
dikes, was enthusiastic about Hans
Hill's invention. They wanted to see
whether it could be useful in Dutch dike
construction and they commissioned
a large-scale study of new and existing
dike-revetment blocks in the new Delta
Flume.
There is also increasing interest abroad
in the Hill Block. ‘But at the moment
we have more than enough to do in the
Netherlands.’
Family company
Alongside Hans Hill, the Hill Block team
now includes four people, including his
wife and daughter. They work from an
office on the 19th floor of the World
Trade Centre in Rotterdam. While con-
tinuing his work as an inventor, Hans
Hill hasn't entirely given up on his old
job of making photographs and films. ‘I
still go and have a look at the Zeeland
bridge near Zierikzee from time to time.
When there's a big storm, I make films
to see how the blocks respond.’