Mapping climate change - barriers and opportunities for action

More frequent storms will pose a challenge for road sign portals:
More powerful storms will expose road sign portals to greater force.
Permanent links:
Rising water levels and precipitation may affect Danish permanent links:
For the permanent links cross the Great Belt and the Sound an increase in precipitation will
mean a greater amount of surface water which will have to be pumped up from surface
drainage systems in tunnels and roads. This in turn means there may be a greater demand for
pumping capacity. A rising water level and more powerful storms may combine to enhance
the risk of flooding of tunnels and lead to longer periods of interruption. More powerful
storms may also mean that bridges will have to be closed down temporarily more often.
Division of responsibilities between the authorities and private citizens
It is the responsibility of the individual road authority to dimension road drainage systems to meet
the recommendations in Danish road regulations. In situations with flooding and damage to sewer
lines, the responsibility rests with the individual owner of the line. This applies to all types of line.
Section 102(4) of the Danish Public Roads Act stipulates an absolute ban on diverting wastewater
onto road surfaces, including into trenches and road drainage systems.
In situations with extreme downpours, in which sewer lines are insufficient to manage the water
amounts, the road authorities may make claims for compensation against the owners of the sewer
line if they can substantiate that the owner has neglected to maintain his lines to a sufficient
capacity.
With regard to surface water run-off from adjacent land at higher ground, the road authorities are
however not protected under the Danish Public Roads Act.
Possibilities for adaptation
With warmer winters, the thickness of the sand and gravel layer (i.e. the anti-frost layer) may be
reduced. The resulting reduced amount of raw materials required for the anti-frost layer means
construction costs will be reduced. However, studies are still needed to determine the frost-free
depth. Warmer winters also provide opportunity for using alternative road surfaces which e.g.
reduce the risk of aquaplaning, mitigate the discharge of pollutants into the surroundings, and which
have noise-reducing properties. Application of salt may however be difficult on certain types of
alternative road surfaces, and the durability of these surfaces may be poorer than that of traditional
materials.
When planning and constructing new roads, the road drainage system will be dimensioned so it can
manage considerable amounts of surface water. This dimensioning of the capacity of the drainage
system must, however, be performed on the basis of an assessment of the financial costs as well as
the risk linked to the system's inability to cope with every conceivable situation. In socio-economic
terms, it will not be cost-effective to dimension a road so that it can withstand every conceivable
situation.
Opportunities also exist for testing alternative drainage methods. For example, the Kliplev-
Sønderborg motorway in the southern part of Jutland has been fitted with linear drainage. If it turns
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