This environmental impact assessment for Kriegers flak ... - Vattenfall

70 PRESENTATION OF THE AREA
1995). During normal winter storms the water level in
Kattegat increases and, in comparison to the southern
Baltic, there will be a height difference of ca 1 metre.
This increased water level generates a greater inß ow
of salt water from Kattegat via Öresund, increasing the
Correlation between wind speed and current flow speed
salination level in the Baltic. Periods of Þ ve to ten days
of storm will also increase saltwater currents through
the Bælts for the same reason.
With a frequency of three years or more, large
additions of salty water occur caused by prolonged
winter storms preceded by periods of high pressure,
forcing water from the Baltic, thus lowering the water
level considerably. This prolonged inß ow means that
the Belt sea front, where the bracken water mixes with
the salty sea water, is shifted forward to the Darss
threshold. This makes it possible for a mixed water
plume with a salinity of at least 17 PSU to move into
the Arcona basin and later Þ ll up the other basins with
heavy and oxygen rich water. These large additions of
salty water are less frequent, resulting in a shortage of
oxygen in the deep basins of theBaltic.
11.2.2 Salinity, temperature and oxygen
content
The area at and around Kriegers Flak is hydrologically
well documented. SMHI has since 1958 a measuring
station in the Arcona basin east of Kriegers Flak measuring
temperature, salination and oxygen content once
or twice a month at each Þ ve metre interval from the
surface down to a depth of 45 m (BY2). This measuring
series can be downloaded from www.smhi.se.
IOW in Rostock is working on a model for the salt
level balance of the entire Baltic, taking into account
the cumulative effects of establishing a number of
offshore wind farms. Results should be known during
2005.
On behalf of the Group, the water conditions around
Kriegers Flak have been researched continuously by
IfAÖ during 2002-2003. This was carried out simultaneously
with other water related environmental
Hydrographical data (median values +/- SD) during the three fishing campaigns in the test area in 2003
Spring 2002
Salt content
[PSU]
Water temperature
[C°]
Oxygen content
[mg/l] [% fullness]
Surface Seabed Surface Seabed Surface Seabed Surface Seabed
Median values 7,6 7,9 15,6 13,9 9,1 8,6 91,5 83,1
Standard deviation 0,2 0,6 0,3 1,3 0,2 0,2 1,9 1,9
Differens surface/seabed
Measurements: n=10
-0,3 1,7 0,5 8,3
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