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FEATURE STORY 55
how development will change these factors. The Alter ra
group is trying to integrate meteorological and hydrologi-
cal models and use them to evaluate various scenarios of
climate and land-use change. "All the di erent components
of the model are available somewhere," says Eddy Moors,
a hydrometeorologist at Alterra. "There s a Dutch model,
a Ger man model, a hydrological model, a meteorological
model. It s a matter of nding a way to combine those com-
ponents, more than inventing something new."
One of the factors the researchers are considering is
that radical changes are expected in European land use.
Dutch planners say that by 2050, European agricultural
land totaling an area larger than Germany will give way
to development or, in some cases, revert to forest. That,
in turn, will a ect the way oods propagate---by altering
the ability of the land to absorb water, for example. "If we
take these changes into account and look into land use, we
can perhaps promote some land-use changes which will
assist us," says Moors. "We want to see the feedback of
those changes." As part of his study, Moors has even been
investigating how trends in land use might change the local
weather. By running meteorological models, he found that
tur ning farmland into forest is likely to stimulate more
local precipitation. Whether this is good or bad depends
on whether it happens during a summer drought or a win-
ter ood. Either way, analyzing such e ects is important to
understanding the larger system.
In addition to forecasting the e ects of changing land use,
the Alterra group is trying to predict the e ects of intensi ed
weather extremes. The Intergovernmental Panel on Climate
Change, the U.N.-sponsored body whose work represents
the global scienti c consensus on the subject, recently pre-
dicted that warmer temperatures worldwide could make
droughts harsher and precipitation more intense. And in
winter, precipitation will tend to fall more as rain than snow
in some areas, including the Swiss Alps, at the Rhine s head-
waters. As a result, wintertime river ooding---already a
problem in the Netherlands---could get far worse. Bu er sys-
tems of some kind will probably be required. These might
be impoundment areas upriver, perhaps even in Germany,
or underground tanks beneath Dutch developments. But
planners need to know where to put these bu er systems,
and how to manage them so they re empty when deluges
are expected but full when droughts are near. This calls for
better long-range forecasts. "To adapt, it is important to have
forecasting systems," says Moors. "To be able to do that, you
have to couple meteorology and hydrology models."
Developing these sharper predictive tools is a pursuit
common to planners in The Hague, New York City, and
Califor nia (see "Planning for a Climate-Changed World,"
May/June). But in the Netherlands, the need is acute. "Our
whole country is at stake," says Piet Dircke, director of the
water program at Arcadis, an engineering and consulting
rm based in Maastricht that is participating in national
planning e orts. "So we are moving from an engineering
kind of approach to a systems approach. You never know
which part is going to change, and which one will be rel-
evant, until you look at the complete system."
Once the risk analysis is complete, it will help guide deci-
sions on where and how to build. Development is already
restricted in some stretches of river oodplains and may
soon be in others. But with
population continuing to
rise, there s great pressure to
develop tracts of low-lying areas
like those in the southwest pol-
der. And besides, defying the
sea is a point of patriotic pride.
"It is our culture to cope with
water," says Chris Zevenbergen, director of business devel-
opment at the construction company Dura Vermeer and a
professor at the Unesco-IHE Institute for Water Education
in Delft. "Retreat would give a very bad signal to the world.
Suppose we are not building; this will have an enormous
impact on the climate for foreign investment. And from a
technological point of view, [construction] is feasible. We
need to adapt to that kind of development."
To demonstrate what is possible, Dura Vermeer has
built a oating housing development in a hamlet called
Maasbommel, in the r ural province of Gelderland, near
the center of the country. There, 46 amphibious houses are
perched on the outer edge of a dike that holds back the River
Maas, adjacent to a marina. Sixteen are oating at the riv-
er s edge, in conjoined pairs, with sealed hollow basements
providing buoyancy. Between each pair of houses are two
vertical concrete piles; if water levels rise, the houses rise
around the piles. Flexible water, sewer, and electrical con-
nections are una ected. Thirty similar houses sit on slightly
higher ground, on concrete slabs a meter or so above the
waterline. They, too, have piles and hollow basements that
"Katrina raised awareness in the Netherlands.
To the general public, it wasn't, 'Silly Americans
can't take care of water management.' It was,
'Oops---this can happen' ... a feeling of solidarity."
To experience historical and possible future flooding in the
Netherlands, visit technologyreview.com/holland.
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