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

CHAPTER VI: WATER
climate change, including risk management in one coast area aquifer. The results
obtained from this case study can be applied to other similar aquifers, as it outlines
possible threats that would impact shallow groundwater resources, considering the
implications for the management of water resources in different sectors. On the
other words, on the basis of this one case study it was possible to create a model of
potential risks for groundwater and water supply at this aquifer.
The selected case study area was a large sand and gravel formation at Hanko
peninsula, Hanko aquifer, in the Southwestern coast of Finland. The Hanko aquifer
was chosen because the permeable sand and gravel layers of this aquifer extends
until the seashore, the water of the aquifer is in public use, and there are lots of
human activities in the area. In addition, the hydrogeology of the area had already
been studied intensively, so that much data was available. Also, the Hanko Town
Water Work was a very cooperative partner. There are several of comparable
aquifers in Finland, in Sweden and in other countries on the coastline of Baltic
Sea, so that the results may be easily adapted to other areas.
The potential effects of climate change on the Hanko shallow groundwater
resources and infrastructures would cause risks not only from the change of
precipitation and warmer temperature, but also from the rise of sea water level,
making the coastal aquifers more vulnerable to this change than the aquifers in the
main land. The study also describes how the infrastructure and management of
Hanko Water might economically adapt and respond to changes in climate, in
context of higher future population and change in land use and technology.
Shallow groundwater resources have been studied extensively in Finland, and
some local groundwater risk assessment has been done, but the study of effects of
climate change on coastal aquifers is a new point of view. The discussion of all
these factors together in relation to a coastal aquifer is also new.
6.2 METHODOLOGY AND MATERIALS
Method and materials
The study method was to produce knowledge about risk assessment and risk
management concerning groundwater in one coastal aquifer. The results provided
from this case study area can be applied to other similar aquifers. Some
information was collected from previous studies and a part produced by this
current study.
All available data from Hanko aquifer was collected. Data was mainly
collected from the Geological Survey of Finland, the Hanko Town Water Works,
the Uusimaa Regional Environment Centre, and the Finnish Institute of Marine
Research (FIMR).
The most empirical and original part of the material, the groundwater level
monitoring data of the Hanko aquifer, was produced by GTK between 12 February
2007 and 12 June 2007 in two observation wells owned by Hanko Town: HP306
observation well in the north-west side and HP66 observation well in the southeast
side of the aquifer. The locations of the observation wells are shown in Figure
5. The observation well HP306 is located in the Hopeasanta beach, about 100 m
from the coast and about 100 m from the Hanko Town main water works. The
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