RD&D-Programme 2004 - SKB

model that includes these factors and processes. Such a model can then be used to describe
historical and possible future shorelines. The project will use the calibrated ice sheet model
described above. The GIA modelling can also provide feedback to the ice sheet modelling,
since the change in the shoreline is evidence of what ice load the earth’s crust may have been
subjected to.
21.2 Permafrost domain
Permafrost is divided with respect to its thickness into sporadic, discontinuous and continuous.
The presence of permafrost, or rather of frozen ground, affects the hydrological conditions.
Groundwater recharge is assumed to decrease and the groundwater flow is limited to unfrozen
ground. Salt exclusion affects the groundwater composition.
Conclusions in RD&D 2001 and its review
SKB observes that current knowledge concerning the occurrence of permafrost in Scandinavia
far in the future is limited. Moreover, the hydrological conditions and groundwater composition
caused by permafrost should be studied more closely. SKI considers it positive that SKB is
planning co-ordinated efforts to investigate permafrost.
Newfound knowledge since RD&D 2001
A literature review of permafrost, with a focus on hydrology and conditions in the bedrock, has
been carried out /21-22/. The study concludes that even though some information is available on
permafrost at greater depth from e.g. the arctic mining industry, most references deal with nearsurface
processes. An important observation is that permafrost in general does not occur beneath
large lakes and rivers. Furthermore, exclusion of salt and hydrates occurs in today’s permafrost
areas. It can also be observed that mechanical effects of freezing are limited to the surface or
near the surface.
(m)
Continuous Discontinuous Sporadic
100
200
300
400
500
0 5
(km) 0 5 (km) 0 5
(km)
Figure 21-4. Illustration of sporadic, discontinuous and continuous permafrost.
Permafrost
Unfrozen ground
Lake, sea
298 RD&D-Programme 2004