NREL - National Renewable Energy Laboratory

Evaluation of the Effect of Sediment Spill from Offshore Wind Farm Construction on Marine Fish

Publication TypeReport
Year of Publication2001
Document Number1980-1-03-2-rev.1.UK
Pagination18 pp.
InstitutionBio/consult as
CityÅbyhøj, DK

The purpose of this memo is to evaluate the possible effects of sediment spill from construction of off-shore wind farms on fish. As part of a plan to establish offshore wind turbines in Denmark, the Ministry of the Environment and Energy introduced a government order asking the electricity companies to set up five large-scale offshore wind farms with a total output of 750 MW.

Rødsand in the Femer Belt was selected as the location for one demonstration project with an output of 150 MW.

The project was approved on the condition that an EIA (Environmental Impact Assessment) study was conducted in accordance with the guidelines of the Ministry of the Environment and Energy. Permission was also given to carry out the necessary preliminary studies.

The offshore wind farm at Rødsand may potentially affect the fish population in the area, during both construction and operation of the wind farm. This paper attempts to estimate the effect of sediment spill from construction of the wind farm on the behaviour and physiology of the fish species known to be present in the area of the proposed wind farm (Bio/consult, 2000a, b).

Four types of construction have been proposed each with a different amount of estimated sediment spill (see Table 3). In the paper an evaluation of the effect of construction is made for all four construction types, although a spill scenario only exists for type 1 (DHI, 2000).

Different life stages of fish have different sensitivity to suspended sediment. Thus, in order to make a meaningful evaluation of the possible effects of suspended sediment on fish, it is essential to make an evaluation for each of the life stages. The paper evaluates
the sensitivity of:
1. Eggs
2. Larvae
3. Juvenile fish
4. Adult fish

Different fish species are affected differently by suspended sediment. This may be due to for example size, physiological differences of the gills and behavioural differences.

The presence of the different life stages and species at Rødsand at the time of construction is included in the evaluation.

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TagsDenmark; Offshore Wind; Fish (general); 2001; Report