Towards a Baltic Sea Region Strategy in Critical ... - Helsinki.fi

CRITICAL INFRASTRUCTURE PROTECTION IN THE BALTIC SEA REGION
rise of 1.30 m during the storm surge of 09 January 2005 (based on the
observations since 1887, (FIMR 2007)). Therefore, by the end of the 21 st century
the sea level rise in Hanko coastal area could possibly reach approximately 2.64 m
in the high case scenario. Figure 11 presents the topographic map of the Hanko
coastal area. The areas below a two-metre-contour line are vulnerable to flooding.
This may affect not only the aquifers but could also cause some land loss.
Figure VI—11 Topography map of Hanko main groundwater area with a 2-metre-contour line
in red. (Modified from Breilin et al. 2004)
Change of Groundwater Properties Through Changing Temperature
Warmer temperatures would change the pattern of precipitation and evaporation,
which would possibly affect the hydrological system, groundwater resources and
their management. In south Finland, by the end of the 21st century winter
temperatures could increase by as much as 6.5 °C and precipitation might increase
by 10-20% (Kropp 2007). Because the recharge of Hanko shallow groundwater is
mainly from snowmelts and rainfall, the earlier snowmelts and the longer hot and
dry summer could cause higher evaporation and mean less water recharge to the
aquifer. This could cause a lower groundwater level, and consequently the
reductions of the groundwater budget. On the other hand, increased precipitation
(10-20 %) may cause increase of the groundwater table. It is also possible that the
changes in precipitation and in temperature and evaporation may compensate each
other.
208 NORDREGIO REPORT 2007:5