Part B - Technical instructions 
23 
Table 1.7: Investigation of benthos, habitat structures and habitat types in the context 
of installation of cable routes for connecting offshore wind farms. The in the 
following described monitoring programme has to be conducted by the grid 
operator. 
The following investigations have to be implemented by the grid operator. 
Baseline study 
Construction 
phase 
Operation phase 
Objectives 
Description of infauna and 
epifauna, habitat structure and 
habitat types as a basis for eva 
luating potential impacts by con 
necting offshore wind farms to 
the grid. 
Medium and small scale survey of 
infauna and epifauna as a basis 
for assessing potential impacts 
during the construction phase. 
Scope 
The distribution of stations follows the habitat structures as determined by SSS/ 
ground truthing (SSS investigations by transmission system operator). 
Each determined habitat structure along the cable route must be covered by at least 
3 cross-transects. Both at the beginning and end of the cable route an additional 
cross-transect must be established. 
Each cross-transect consists of 5 stations (see study design, fig. 3, p. 43). The central 
station is located on the planned cable route. 2 stations are located in 100 m and, 
respectively, 1,000 m distance above and below the central station. 
Identified areas suspected to be protected habitat types as per § 30 BNatSchG shall 
be demarcated by additional investigations according to the currently valid mapping 
guidelines of the BfN. In the event of numerous small scale areas, the representative 
distribution of stations is possible on the basis of the SSS investigations and in agree 
ment with the BSH. 
Timing 
Once in autumn. 
Once in autumn one year after 
commissioning of the cable. 
Method 
Sampling strategy infauna: 
• The seasons are defined as follows: Autumn: 15.08.-15.11. 
• 5 stations per cross-transect are investigated, each consisting of 3 parallel 
samples. 
• Equipment standard: Modified van Veen grab, 0.1 m z sampling surface, 60-80 kg, 
sieve covered lid, warp-rigged. Grab sampling depth may vary depending on sedi 
ment conditions. Should the grab sampler weight require adaptation to the sedi 
ment structure (e. g. 25-40 kg for muddy/silted sand and 70-100 kg for coarser 
sediments, depending on the grab sampler’s starting weight), this must be effected 
in such a manner so as to maintain the comparability of sampling stations with 
similar sediment structure. 
• Sieve with 1,000 pm mesh size. In case of large proportion of coarse and medium 
grained sand or gravel, the sample should first be decanted through the sieve and 
rinsed at least five times. This is followed by batch-wise sieving. Fixation of the 
sample in 4 % buffered formalin. 
• Sample processing must be documented and standardised 
(according to ISO/DIS 16665). The condition of the catching device must be docu 
mented. 
• Biomass shall be determined as wet weight per species 
(according to ISO/DIS 16665, Annex C).