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

30 DESCRIPTION OF THE WIND FARM
5.5. Obstacle marking of the turbines
The Maritime Administration and the Civil Aviation
Authority will decide the exact obstacle marking of
the wind turbines.
During the construction phase, the area will, wherever
necessary, be marked with light buoys.
According to the Maritime Administration, they
will decide that during the construction phase, all
wind turbines will be marked with luminous tape.
The corners of the wind farm and the sides every two
nautical miles will be marked with a yellow ß ashing
hazard light, night-time lightening and numbers. The
towers will be painted yellow up to 15 metres above
the mean water level or, alternatively, with horizontal
yellow/white tape with a minimum width of two metres.
Lights, names and spotlights will be mounted 15
metres above the highest water level. To further protect
against collisions, the Morse Code letter “U” will be
ß ashing continuously. The maritime obstacle marking
will be in accordance with international recommendations
issued by IALA.
Currently, the rules and regulations surrounding
hazard lights are being reviewed and are expected to
be ready during the spring 2005. Proposals for hazard
lighting are being made by individual countries and
the Þ nal rules will thereafter be decided by ICAO, the
International Civil Aviation Organisation.
As the height of the wind turbines is likely to
exceed 150 metres, they will probably be equipped
with ß ashing lights. According to the Swedish Civil
Aviation Authority, the highest point of the turbine, i.e.
the tip of each rotor blade, should be marked. In view
of several important arguments against this marking,
the Authority seems to have abandoned this idea. Instead,
the thinking now is to place the ß ashing light on
top of the nacelle.
The following working hypothesis for wind turbines
higher than 150 metres is currently (November 2004)
being used by the Authority:
The tower shall be equipped with a low-intensive
red light at two locations.
The nacelle shall be equipped with one high-intensive
light that ß ashes 60 times per minute.
The light will be directed so that it will not be visible
on the ground within a distance of 5 km from the
wind turbine.
As mentioned above, this is only a Swedish working
hypothesis and it is currently not possible to have a
Þ rm view on future obstacle marking.
5.6. Description of the different
project phases
5.6.1. The Development phase
During the period 2002 – 2004 several surveys have
been carried out (see chapter 19.1). The most important
of these are summarised below.
a) Geophysical and geotechnical surveys.
In order to gain information about the impact on
seabed-based ß ora and fauna and to be able to work
out foundation proposals, the seabed has been investigated
using different geophysical methods. The seabed
proÞ le has been studied using sonar and the structure
of the surface layer has been studied using sidescan
sonar. To gain information about sedimentary strata
and the distance to solid rock formations, a seismic
boomer was used. These investigations were carried
out by the companies Weigt and Marin Mätteknik. In
order to chose a suitable technique and to calculate the
dimensions of the foundations, test drillings have been
conducted on the German side of Kriegers Flak.
Furthermore, an inventory of the available geotechnical
and geophysical studies that have been carried out
in Denmark and Sweden has been made by SGI.