Water as Leverage - Wadden Sea Region

Water as Leverage for Climate Adaptation: Wadden Sea Region
Ribe
Water threats
from all sides
Challenges
HERITAGE IN DANGER!
In the city of Ribe, the stream
is raised via four stems (small
sluices). This heightened water
table heavily affects the humidity
and groundwater level of the soil,
which consists of a high percentage
of organic material. How come?
Historically, new buildings were
always built on the debris of the old
ones (often in wood), creating a soil
which contains organic materials.
In short, they call this kind of soil a
‘cultural swamp’. It renders the soil
very sensitive to changing humidity
conditions. As such, the current
water table must be maintained or
sometimes even kept high enough
as to not compromise the structural
characteristics of the old buildings.
Changes in the urban fabric have
proven to be dangerous — for
example, the recent repavement
of the square around the church
affected the water table and the
consistency of the soil, which
impacted the stability of some
old buildings, as cracks started to
appear. Climate change is bringing
periods of more extreme rainfall and
drought, thus surely impacting these
soil conditions even more, putting
the valuable built heritage of the city
at risk.
WATER FROM THE EAST,
WATER FROM THE WEST
Each year, Ribe has to deal with
flooding, coming from different parts
of the water catchment area. There
is an excess of water coming from
the whole catchment area in the
east, which spans over 960 km 2 . In
winter times, the land more upstream
becomes too saturated with water,
which causes a sudden flash flood
— or flom — to arrive in the urban
center of Ribe. The stems, which
regulate the water level, cannot
handle this huge amount of water,
and the river exceeds its borders.
The waterways in the city center are
literally bottlenecks, and flooding
happens regularly.
From the west, the water threat
is coming from the sea. The sea
dyke with the sluice Kammerslusen
was built in 1912 and is currently 7
meters high. This infrastructure is
a critical point in the whole water
protection of Ribe on two levels. On
the one hand, the dyke and sluice
need to be renewed in the future in
order to deal with the predicted sea
level rise. On the other hand, there
are currently floods happening when
the discharge of water through the
sluice into the sea is not possible.
There is a build-up of water at the
level of the sluice, and when heavy
rains occur, this huge amount of
water reaches the city center of
Ribe. The area between the dykes
and Ribe city is covered by the water
every year during winter months.
More and more often, the water
even reaches the city center... It is
inevitable that this will only worsen
in the future, when heavy rains occur
more frequently. This two-fold threat
in the west poses a lot of questions
related to the renewal of the dyke
and sluice.
10
Ribe