Geography Reference
In-Depth Information
More comprehensive approaches to working with, and not against, nature, have
been developed by the Dutch (Bezuyen et al.
1998
Saeijs
1991
; Kabat et al.
2005
;
Scheur et al.
2011
). For centuries they have reclaimed land from the sea and flood
plains by ingenious reclamation techniques and through co-operative efforts. In
the last two decades they have recognized that the increased size and frequency of
floods during this period of global warming means that the older engineering control
solutions alone are not going to be adequate to solve the problems posed by future
flooding levels, solutions that are still being applied world-wide (Zevenbergen et al.
2012
). Hence they have adopted new ideas. One is the '
Building with Nature'
ap-
proach, which attempts to work with nature, rather than only attempting to dominate
or control it. Artificial barriers have been placed in coastal shallow seas, which al-
low natural processes to create salt marshes, while sand dumps have been created to
provide a source of material which will be used by tides and winds to build up exist-
ing dunes that are themselves stabilized by vegetation and will form a more effec-
tive natural barrier against storms. Along water courses the new '
Room for a River'
strategy is important (Rohde et al.
2006
). It recognizes that confining flows through
higher and higher embankments will not cope with the predicted larger and more
frequent floodwaters in rivers. Certainly strengthening embankments with rocks and
concrete on bends still have a place in the fight against floods. But it is realized that
a more effective risk reduction strategy is to create more room for a river, rather than
only artificially confining it, by policies applied not only in one area but throughout
the water-basin. Hence rivers are being given more room in which to flood, such as
by: moving dykes back to widen the rivers; deepening channels to increase water
flow; lowering groynes that protrude into the river and reducing flow obstacles;
removing some riverside areas from current use to act as storage areas or flow chan-
nels in flood conditions. All these areas that are created to make room for floods are
grassed and pathways are added to create new park areas. These add significantly to
the recreational areas of cities, at least when the river is not in high flood. In cities
such as Dordrecht experiments have been carried out to see how flood water affects
particular housing areas, in order to create more effective flood prevention, while
regulations for infra-structure and buildings are designed to minimize water dam-
age. One of the most striking examples of the application of these ideas is taking
place in the city of Nijmegen in the Netherlands. Located mainly on the south bank
of the river Vaal, it grew up around major river bridges that span a river which nar-
rows in a major bend as it passes the city. This made crossings easier, but ensured
that the settlement has always been at risk from flooding. Radical new solutions are
being implemented: moving the northern embankments on the river back an average
of 350 m; creating an artificial channel on the north bank for the main river channel
to straighten out the river to improve flow, which will create an island between the
two river branches; raising the land-level in new urban developments on the north
bank to reduce flood risk; adopting many of the other techniques described above to
widen the river to accommodate high flood levels. The result of the changes will be
to reduce the flow in the old river channel on the edge of the city. The old river chan-
nel and the new island will become a new recreational area within the city, rather
than a dangerous peripheral feature that has often overwhelmed the city with major
