Aarhus Universitets segl

Kortlægning af områder med forøget sandsynlighed for landsænkning

Publikation: Bog/antologi/afhandling/rapportRapportForskning

  • Niels Henrik Broge, Geodatastyrelsen, Danmark
  • Karsten Vognsen, Geodatastyrelsen, Danmark
  • Frands Steffensen, Geodatastyrelsen, Danmark
  • Ian B. Sonne, Geodatastyrelsen, Danmark
  • Carlo S. Sørensen, Kystdirektoratet, Danmark
  • Per Knudsen, DTU Space, Danmark
  • Mogens Humlekrog Greve
  • Holger Lykke-Andersen, Danmark
Land subsidence has been observed locally on dikes, in urban areas residing on land fill deposits, in areas dominated by bogs and meadows as well as in rural areas where drainage is predominant. Despite this fact, no systematic mapping of land subsidence zones or rates has yet been attempted in Denmark. Plausible explanations are that such an attempt may be very labour intensive, and that land subsidence issues have not gained much attention in a national context
up until the present. Furthermore, the levelling points of the Danish reference network have been established in areas considered to be relatively stable with respect to vertical land movements, thereby making an assessment difficult.
However, there now is an increasing demand for knowledge in the public about land subsidence and vertical land movement in general, amongst other things in relation to climate change adaptation and construction works at the municipality
On this basis, a map of areas with an increased probability of land subsidence at the local scale has been produced in collaboration between the Danish Geodata Agency, the Danish Coastal Authority, the National Space Institute and the University of Aarhus (refer to figure on page 6). The map has been produced from the union of selected soil maps, geological maps and geospatial
information about low-lying areas and areas characterized by landfill. The geological maps comprise registrations of freshwater sediments (peat, mud, clay and sand), landscape elements (Littorina deposits, young marine deposits and
reclaimed areas) and lowlands (bogs, meadows and marsh). Low lying areas (0–3 m a.s.l.) have been identified using the national digital elevation model (DK-DEM) and landfill areas around major harbours have been digitized using the
most recent available orthophotos.
The mapping process was supported by calculated rates of vertical change based on time series
of selected calculated heights from GST’s database of levelling measurements, and used to validate the map.
The map represents a first attempt to identify areas with increased likelihood of land subsidence at the local scale. This is expected to form the basis for further development and research work on land subsidence in absolute values and mapping in Denmark.
Antal sider32
ISBN (Trykt)978-89-72107-62-6
StatusUdgivet - 2013

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