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

158 CONTROL PROGRAM
14.4 Current conditions
In order to get a comprehensive view on the hydrographic
impact that the turbines cause, a proposed
control program has been developed by SMHI (Attachment
13.3).
The program intends to map the average salt water
levels and the variability during the season that the
mixing is most intense and it is most likely that an
inß ow occurs. The survey is conducted by measuring
the water ß ow with acoustic current-meters mounted
on the seabed at various positions at Kriegers Flak
during a period of three autumn or winter months. The
salt level and temperature variations are also measured
during this period.
In connection with the installation, recovery and
service of the measuring instruments, information is
gathered by acoustic current-meters mounted on ships
as well as by a salt and temperature probe.
To get a detailed picture of the variation of the
mixing process close to a wind turbine, the turbulence
around a wind tower is measured from a ship using a
free-falling microstructure meter, which also measures
salt levels and temperature ß uctuations. The measuring
is done during an intensive period of about one
week. Information about the current in lee of the tower
is measured during the same intensive period with a
ship-mounted acoustic current meter. From these readings,
a detailed picture of the increase in turbulence
and mixing can be calculated.
A calculation of the total effect of all the towers in
the farm can therefore be made using the mapping of
the mean condition.
The procedure enables a complete veriÞ cation of the
calculations done on the farm’s impact on the deep-water
situation in the Baltic Sea.
14.5 Shipping / Risks
A proposed control program for shipping has been developed
by the SSPA. The program will verify that the
calculated risks have not been underestimated and it
will be focused on minimizing risks and consequences
of collisions between ships and the farm.
During both the development and operational
phases, the area will be sectioned off and surrounded
by a safety zone. The program includes routines and
information duties for the follow-up of the sea traf-
Þ c that passes by the farm, measures for when ships
deviate from the recommended distance of passage,
measures if there is risk of collision, as well as measures
if a collision occurs. The different parties will be
identiÞ ed as well as their responsibilities and tasks to
ensure that the program is obeyed effectively. Special
measures for smaller ships including Þ shing boats and
recreational vessels will be given. Responsibility for
the information will be speciÞ ed.
The proposed control program in Attachment 12.3
should be seen as a backbone of a more complete
program. An operative control program can only be
developed when the conditions for the construction of
the farm have been formulated, areas for sectioning
off etc. have been decided and actions and decisions
within the German and Danish zones have been made